---
canonical_name: Sh-Polypeptide-11
alternate_names: rh-Oligopeptide-13, rh-Polypeptide-11, rh-FGF1, rh-aFGF, Acidic Fibroblast Growth Factor, aFGF, FGF1, CG-aFGF
canonical_topic: Sh-Polypeptide-11 for Hair Regrowth
short_topic_lc: sh_polypeptide_11_hair
creation_date: 2026-0628-0047
creator_ai_fullname: Opus 4.8
---

# Sh-Polypeptide-11 for Hair Regrowth

Evidence Review created on 06/28/2026 using [AI4L](https://github.com/forever-healthy/AI4L) / Opus 4.8

**Also known as:** rh-Oligopeptide-13, rh-Polypeptide-11, rh-FGF1, rh-aFGF, Acidic Fibroblast Growth Factor, aFGF, FGF1, CG-aFGF

## Motivation

Sh-Polypeptide-11 is a lab-made copy of a natural human signaling protein called acidic fibroblast growth factor (a messenger that tells skin cells to multiply and repair). It is made in cell cultures and added to topical serums for the scalp and skin. The interest for hair comes from a simple idea: the same signal that drives wound repair and the growth of skin-building cells might also coax resting hair follicles back into an active growing phase.

Growth-factor ingredients like this one have spread quickly through high-end hair serums, often marketed as a gentler alternative to standard hair-loss drugs. Most of the direct hair evidence so far comes from laboratory and animal work, where members of this protein family pushed resting follicles into growth. Human hair data specific to this ingredient remain very limited, the central tension this review addresses.

This review examines what is actually known about Sh-Polypeptide-11 applied to the scalp for hair regrowth: how it is thought to work, what the benefit and risk evidence shows, how it is typically used, and where the gaps in the evidence lie.

**[Benefits](#expected-benefits) - [Risks](#potential-risks--side-effects) - [Protocol](#therapeutic-protocol) - [Conclusion](#conclusion)**

## Recommended Reading

This section lists high-level resources that give useful context on growth-factor peptides and hair regrowth for a non-specialist reader.

* [#316 – AMA #63: A guide for hair loss: causes, treatments, transplants, and sex-specific considerations](https://peterattiamd.com/ama63/) - Peter Attia

  A structured clinician overview of androgenetic hair loss and its treatment options, useful for placing growth-factor serums within the broader, better-evidenced landscape of minoxidil, finasteride, and procedural therapies.

* [sh-Polypeptide-11 – CG-aFGF](https://ci.guide/peptides/sh-polypeptide-11) - Ghochikyan

  An ingredient monograph that identifies Sh-Polypeptide-11 as recombinant acidic fibroblast growth factor and summarizes its proposed actions on fibroblasts, hair cells, and blood vessels, with primary references.

* [Sh-Polypeptide-11](https://www.stratiaskin.com/blogs/ingredients/sh-polypeptide-11) - Stratia

  A plain-language formulator's explainer of what the ingredient is and why it is used, helpful for understanding how this growth factor is positioned in consumer products.

* [sh-Polypeptides: Growth Factors That Regrow Hair](https://www.juventudeskincare.com/blogs/founders-journal/growth-factor-complex-in-hair-serums-the-science-behind-sh-polypeptides-for-hair-growth) - Lindsey Walsh

  A founder's overview distinguishing the various sh-polypeptide growth factors used in hair serums, clarifying how Sh-Polypeptide-11 differs from related FGF and KGF analogues.

* [Growth Factors in Hair Serum](https://xyonhealth.com/blogs/library/growth-factors-in-hair-serum) - Ciera Parsons

  A clinically framed discussion of how growth factors in topical hair serums are proposed to work and what the human evidence does and does not yet support.

*Note: Of the five priority experts, only Peter Attia had directly relevant high-level content (on hair loss generally); no priority-expert content named this specific ingredient. Five eligible items were found, so the list is complete and not padded.*

## Grokipedia

No Grokipedia article exists for Sh-Polypeptide-11.

## Examine

No Examine article exists for Sh-Polypeptide-11. Examine.com focuses on orally ingested supplements and does not typically cover topical recombinant growth-factor peptides.

## ConsumerLab

No ConsumerLab article exists for Sh-Polypeptide-11. ConsumerLab tests and reviews ingestible supplements and does not typically cover topical recombinant growth-factor peptides.

## Systematic Reviews

No systematic reviews or meta-analyses for Sh-Polypeptide-11 were found on PubMed as of June 28, 2026.

## Mechanism of Action

Sh-Polypeptide-11 is a recombinant (lab-produced) form of acidic fibroblast growth factor 1 (FGF1, a natural protein that signals cells to grow and divide). It binds to fibroblast growth factor receptors (FGFRs, docking proteins on the cell surface) on several cell types in skin and the hair follicle, switching on internal signaling cascades that drive cell proliferation and survival.

The primary proposed pathway for hair is induction of the **anagen** (active growth) phase. In animal work, members of this protein family drove resting follicles back into growth by activating the **Wnt/β-catenin** signaling pathway (a master switch for follicle stem-cell activation) and **Sonic hedgehog (Shh)** signaling (a pathway that drives follicle downgrowth and matrix-cell division). FGF1 also acts on **dermal papilla cells** (the signaling hub at the base of the follicle that instructs surrounding cells to grow); activated dermal papilla cells then stimulate proliferation of the outer root sheath cells that form the growing hair.

A second proposed contribution is improved local blood supply. FGF1 stimulates proliferation of vascular endothelial cells, which could enhance the small-vessel network feeding the follicle, though the angiogenic signal for FGF1 specifically has been modest and not always statistically significant.

A competing mechanistic view tempers these claims. The FGF family contains both growth-promoting and growth-inhibiting members — FGF5, for example, actively drives follicles out of anagen and into regression, and it can reverse FGF1-driven follicle stimulation. This means the net effect of manipulating one FGF depends on the surrounding signaling context, and a pro-growth signal in a dish or a mouse may not translate to net regrowth on a human scalp. A further limitation is delivery: the intact protein is large and does not readily cross the skin barrier, so any scalp effect depends heavily on the formulation (for example, liposomal encapsulation).

As a recombinant protein rather than a small-molecule drug, classic pharmacological parameters apply differently. Native FGF1 has a short circulating half-life (on the order of minutes once systemic), is not metabolized by cytochrome P450 liver enzymes, and acts locally at the application site. It binds heparin and heparan sulfate in the extracellular matrix, which stabilizes it and modulates its receptor binding; selectivity is broad across FGFR subtypes rather than tissue-specific.

## Historical Context & Evolution

Acidic fibroblast growth factor (FGF1) was first characterized in the 1970s–1980s as a potent mitogen — a substance that drives cell division — for cells of skin origin, including keratinocytes, fibroblasts, and blood-vessel cells. Its original intended use was therapeutic: as a wound-healing and tissue-repair agent. Early rodent studies showed that topically applied acidic FGF nearly doubled the rate of closure of full-thickness skin wounds, and recombinant human acidic FGF was later studied in humans for burns and skin-graft donor sites.

The move toward hair and cosmetic use grew out of two observations. First, the same proliferative signals that speed wound repair also govern the hair follicle, which is itself a regenerating mini-organ; immunostaining studies localized acidic FGF to developing and growing follicles. Second, the broader longevity-oriented and growth-factor skincare movement created a commercial pathway: once recombinant production made the protein available, it was reformulated under cosmetic naming conventions (the INCI name Sh-Polypeptide-11, trade name CG-aFGF) and incorporated into longevity-oriented skin and hair serums.

The actual historical findings are mixed rather than uniformly positive. Animal and follicle-culture studies consistently show that acidic FGF can stimulate follicle cells and induce anagen, but the same body of work also identified FGF5 as an opposing, anagen-terminating signal within the same family. Rather than being "debunked," the early pro-hair findings stand as valid but narrow: they establish a plausible biological signal without demonstrating net human scalp regrowth.

Scientific opinion continues to evolve. A 2025 review of FGF signaling in hair argued that targeting this pathway could eventually exceed current treatments in efficacy and safety, while emphasizing how much of the receptor biology in human follicles remains underexplored. The current position is therefore best read as an open, mechanistically promising question rather than a settled conclusion in either direction.

## Expected Benefits

### Speculative 🟨

#### Stimulation of Hair Regrowth (Increased Density)

The central marketed benefit is that topical Sh-Polypeptide-11 reactivates resting follicles and increases hair count or density. The mechanistic basis is real: in telogen-phase mice, topical FGF family members (including acidic FGF) induced an earlier and prolonged anagen phase with early activation of β-catenin and Sonic hedgehog in follicles. However, there are no published controlled human trials of Sh-Polypeptide-11 (or isolated acidic FGF) demonstrating increased hair density on the human scalp; consumer claims of percentages of users gaining terminal hairs come from unpublished or marketing sources and cannot be independently verified. The evidence basis is therefore mechanistic and preclinical (animal) only.

#### Prolongation of the Active Growth (Anagen) Phase

Beyond simply initiating growth, acidic FGF may extend the duration of the anagen phase, which would translate to longer, thicker hairs. In cultured wool follicles, acidic FGF altered the differentiation program of fiber-producing cells, and in mice it lengthened the mature anagen phase. This benefit shares the same limitation as overall regrowth: it rests on animal and ex-vivo follicle data, with no controlled human scalp evidence specific to this ingredient.

#### Protection of Follicles from Stress-Induced Loss

A distinct potential benefit is follicle protection rather than de-novo regrowth. In a mouse model, acidic FGF (FGF1) reduced radiation-induced apoptosis (programmed cell death) of hair-follicle cells, preventing the premature shift from growth to regression. This suggests a possible role in limiting shedding under follicular stress, but the data are from a single non-scalp, non-androgenetic animal model and do not establish a human benefit.

#### Improved Scalp Microcirculation and Skin Quality

By stimulating blood-vessel and fibroblast proliferation, Sh-Polypeptide-11 is proposed to improve the local environment around follicles (better microcirculation, firmer surrounding dermis), indirectly supporting hair. This draws on its established wound-healing and dermal-firming actions, where human topical data exist for skin (not hair). The angiogenic effect of FGF1 specifically has been reported as small and not always statistically significant, so any contribution to hair is indirect and unproven, and the basis is mechanistic and extrapolated.

## Benefit-Modifying Factors

The following factors may plausibly influence whether any benefit is realized, though none have been formally tested for this ingredient in human hair:

* **Cause and stage of hair loss:** Follicles that are dormant but viable (early androgenetic or telogen-phase thinning) are more likely to respond to an anagen-inducing signal than follicles that are scarred or fully miniaturized; advanced, long-standing baldness is unlikely to respond.

* **Formulation and delivery:** Because the intact protein does not cross the skin barrier well, benefit depends heavily on the delivery system (e.g., liposomal encapsulation, microneedling-assisted delivery). An identical concentration in a poorly penetrating vehicle may produce no effect.

* **Baseline scalp and vascular health:** A healthy, well-perfused scalp with intact follicular stem-cell pools provides the substrate the growth factor acts on; chronic inflammation, fibrosis, or poor microcirculation would blunt response.

* **Sex-based differences:** Patterned hair loss differs by sex in distribution and hormonal drivers, and growth-factor responsiveness has not been characterized separately in men and women; any sex difference in response to Sh-Polypeptide-11 is currently unknown.

* **Age:** Older follicles have reduced stem-cell activity and regenerative capacity, and growth-factor signaling itself declines with age, so older individuals at the upper end of the target range may respond less robustly than younger ones.

* **Concurrent therapy:** Effects may be larger when combined with established treatments or procedures (microneedling, minoxidil), as growth factors are most often studied as add-ons rather than standalone agents.

## Potential Risks & Side Effects

### Low 🟥

#### Local Skin Reactions (Irritation, Redness, Itching)

As with most topical serums, the most likely adverse effects are application-site reactions: mild irritation, redness, itching, or stinging, driven more often by the overall formulation (solvents, preservatives, fragrance) than by the peptide itself. Recombinant acidic FGF used topically in controlled wound-healing and burn studies was generally well tolerated without notable local toxicity. Such reactions are usually mild, reversible on discontinuation, and comparable to other peptide-containing cosmetics.

**Magnitude:** Mild application-site reactions are uncommon, on the order of a few percent of users (roughly 1–5%) by analogy to topical peptide and growth-factor serums, with serious local toxicity not reported in topical recombinant acidic FGF wound-healing studies.

### Speculative 🟨

#### Allergic or Hypersensitivity Response to a Recombinant Protein

Because Sh-Polypeptide-11 is a protein produced in a microbial or cell-culture system, there is a theoretical risk of allergic sensitization or hypersensitivity to the protein or to trace host-cell or process residues. No confirmed cases tied specifically to this cosmetic ingredient are documented, so the concern is mechanistic and precautionary rather than evidence-based, and would be expected to present as localized contact-allergy symptoms.

#### Theoretical Pro-Proliferative / Tumor-Promotion Concern

Growth factors stimulate cell division, which raises a theoretical concern about promoting growth of pre-existing abnormal or pre-cancerous cells in treated skin. This concern is frequently raised for growth-factor skincare in general. For topically applied Sh-Polypeptide-11 the protein's poor skin penetration and local action argue against meaningful systemic exposure, and no human evidence links cosmetic use to cancer; the concern remains hypothetical and unquantified, based on the general biology of mitogens rather than on reports.

#### Unintended Effects from Broad FGF Signaling

Because FGF receptors are widely expressed and the FGF family contains opposing growth and regression signals, an exogenous FGF could in principle produce unpredictable follicular effects (for instance, no benefit or paradoxical responses if the local signaling context favors regression). This is a mechanistic caution drawn from the existence of anagen-terminating family members such as FGF5; it has not been observed as a documented adverse event for this ingredient.

## Risk-Modifying Factors

The following factors may modify the likelihood or severity of adverse effects, though none are formally characterized for this ingredient:

* **Genetic predisposition to skin reactivity:** No pharmacogenetic variant has been validated to modify the risk of topical Sh-Polypeptide-11 specifically, but polymorphisms in filaggrin (FLG, a gene governing the skin barrier) predispose to barrier impairment and atopic/contact dermatitis, plausibly raising irritation and sensitization risk; this is extrapolated from general dermatology rather than ingredient-specific data.

* **Sensitive or compromised skin:** Individuals with eczema, rosacea, seborrheic dermatitis, or a broken scalp barrier are more prone to irritation and to greater (and less predictable) absorption of the protein and excipients.

* **Personal history of contact allergy:** A history of reactions to cosmetic peptides, preservatives, or fragrances raises the baseline risk of a hypersensitivity reaction; patch testing reduces this risk.

* **Pre-existing or prior skin cancers:** Given the theoretical pro-proliferative concern, those with a history of skin malignancy or active pre-cancerous lesions in the application area have a more cautious risk profile, even though no causal link is established.

* **Baseline biomarkers:** No specific laboratory biomarker predicts topical risk; assessment is clinical (skin condition, allergy history) rather than lab-based.

* **Sex-based differences:** No sex-specific safety differences have been characterized for topical Sh-Polypeptide-11.

* **Age:** Older or photoaged, thinner skin may be marginally more reactive to topical actives, though this is a general dermatologic consideration rather than an ingredient-specific finding.

## Key Interactions & Contraindications

Because Sh-Polypeptide-11 is applied topically to the scalp and is poorly absorbed systemically, classic systemic drug–drug interactions are unlikely. Relevant interactions are mostly local and formulation-level.

* **Prescription topical interactions:** Topical retinoids (tretinoin, adapalene) and other potentially irritating prescription topicals applied to the same area can compound scalp irritation; severity is caution-level, and the consequence is additive local irritation. Mitigating action: separate application times or alternate days.

* **Over-the-counter topical interactions:** Concurrent exfoliating acids (glycolic, salicylic acid) or benzoyl peroxide on the scalp may degrade the peptide or increase irritation; severity caution, consequence reduced efficacy and additive irritation. Mitigating action: apply at different times of day.

* **Supplement interactions:** No meaningful systemic supplement interactions are expected. Topical antioxidant serums (e.g., high-strength vitamin C at low pH) applied simultaneously could chemically destabilize the protein; severity is minor (loss of efficacy, not harm). Mitigating action: separate application.

* **Additive (potentiating) combinations:** Other topical hair actives are commonly layered for additive effect — minoxidil (a vasodilator hair-growth drug), other growth-factor peptides (e.g., sh-Polypeptide-1/bFGF, copper tripeptide), and procedural delivery such as microneedling. These may enhance results but also increase total irritation load.

* **Other intervention interactions:** Microneedling and energy-based procedures markedly increase skin penetration of the peptide; this is a potentiating interaction that can raise both efficacy and irritation/absorption, and should be approached cautiously.

* **Populations who should avoid it:** Pregnant or breastfeeding individuals (no safety data; growth-factor signaling is a theoretical concern), people with active scalp infection, open wounds, or inflammatory scalp disease at the site, anyone with a known allergy to the product or its components, and those with active or recent skin cancer in the treatment area as a precaution.

## Risk Mitigation Strategies

* **Patch test before first scalp use:** Apply a small amount to a discreet area (e.g., inner forearm or behind the ear) for several days before scalp-wide use to screen for irritation or allergy, mitigating the risk of a hypersensitivity or contact-irritation reaction over a large area.

* **Start with lower frequency and titrate:** Begin once daily (or every other day) rather than twice daily for the first 1–2 weeks, increasing only if well tolerated, to reduce the risk of cumulative irritation, redness, and itching.

* **Separate from irritating actives:** Apply at a different time of day from retinoids, exfoliating acids, or benzoyl peroxide on the scalp to mitigate additive irritation and to avoid chemically degrading the peptide.

* **Avoid use on broken or inflamed scalp:** Do not apply over open wounds, active infection, or flaring dermatitis, which increases absorption and irritation risk; treat the underlying scalp condition first.

* **Use caution with enhanced-delivery procedures:** When combining with microneedling, follow conservative needle depths and frequencies and allow skin to recover between sessions, mitigating the increased absorption and irritation that aggressive delivery can cause.

* **Precaution in higher-risk individuals:** Pregnant/breastfeeding individuals and those with a history of skin cancer in the area should avoid use or seek individualized guidance, mitigating the theoretical pro-proliferative and unknown-developmental risks.

## Therapeutic Protocol

There is no standardized, evidence-based clinical protocol for Sh-Polypeptide-11 in hair regrowth; usage is defined by cosmetic product instructions and practitioner convention rather than by trials. The patterns below reflect how it is typically used.

* **Standard application:** A leave-on serum containing the peptide (often within a multi-growth-factor or peptide complex) is applied to the affected scalp areas, typically once or twice daily, and left on. This mirrors the regimen used in the closest comparable clinical context (peptide hair serums evaluated against minoxidil).

* **Competing approaches — standalone vs. adjunctive:** One approach uses growth-factor serums as a standalone daily cosmetic regimen; another uses them as an adjunct to established treatments (minoxidil, finasteride) or to procedures (microneedling, fractional laser, platelet-rich plasma). Neither is established as superior for this ingredient; growth factors are most often studied as part of combination protocols rather than as monotherapy.

* **Practitioner context:** Aesthetic and trichology clinics popularized layering growth-factor serums with microneedling or fractional-laser sessions to improve delivery; the cosmetic-ingredient literature (e.g., CG-aFGF positioning) frames the peptide as a high-end serum active rather than a clinic-only therapy.

* **Best time of day:** No circadian timing advantage is established. Practical guidance is to apply to a clean, dry scalp and to avoid washing the area for several hours afterward to allow contact time; if used with other actives, separate by time of day.

* **Half-life consideration:** As a recombinant protein, native acidic FGF has a short biological half-life (minutes systemically) and acts locally and transiently; this short window is part of the rationale for once- or twice-daily reapplication and for delivery systems that prolong follicular contact.

* **Single vs. split dosing:** Because the protein acts locally and briefly, twice-daily (split) application is commonly used to maintain follicular exposure rather than a single daily dose, though no comparative data establish the optimal frequency.

* **Genetic considerations:** No pharmacogenetic variants (e.g., affecting FGF-receptor signaling) have been validated to guide dosing of topical Sh-Polypeptide-11; genetic sensitivity to androgens (the main driver of patterned loss) is more relevant to overall strategy than to this peptide specifically.

* **Sex-based differences:** Dosing is not differentiated by sex in available products; patterned hair loss differs by sex, but no sex-specific dosing for this peptide is established.

* **Age-related considerations:** Older individuals with reduced follicular regenerative capacity may see smaller responses; protocol intensity (frequency, adjuncts) is sometimes increased empirically, without supporting trial data.

* **Baseline biomarkers and conditions:** No biomarker-guided dosing exists; baseline scalp assessment (follicle viability, inflammation, miniaturization) informs realistic expectations more than dose. Pre-existing scalp disease should be addressed before starting.

## Discontinuation & Cycling

* **Lifelong vs. short-term:** Like most hair-growth maintenance approaches, any benefit is presumed to depend on continued use; the underlying drivers of patterned hair loss persist, so stopping is expected to allow gradual reversion over subsequent hair cycles. There is no defined treatment course after which results become permanent.

* **Withdrawal effects:** No specific withdrawal syndrome is documented for Sh-Polypeptide-11. Unlike vasodilator drugs, abrupt cessation is not expected to cause acute shedding; any loss would reflect the natural return of follicles to their pre-treatment trajectory rather than a rebound effect.

* **Tapering:** No tapering protocol is established or considered necessary, given the absence of a withdrawal effect; the product can generally be stopped without a step-down.

* **Cycling:** There is no evidence that cycling (planned on/off periods) preserves efficacy or prevents tolerance for this peptide; receptor-level tachyphylaxis (diminishing response) has not been characterized, so cycling is neither supported nor clearly contraindicated.

## Sourcing and Quality

* **Recombinant origin and identity:** Quality starts with verified identity — genuine Sh-Polypeptide-11 is a recombinant acidic FGF1 protein (INCI Sh-Polypeptide-11; trade name CG-aFGF; FDA UNII G53298VN9Y). Products should list the INCI name accurately and ideally state purity and that the protein is produced under controlled fermentation/cell-culture conditions.

* **Formulation and delivery system:** Because the intact protein penetrates skin poorly, look for a delivery strategy (e.g., liposomal encapsulation) and an appropriate, stable vehicle; the same concentration in a poorly designed base may be ineffective. Concentration alone is a weak quality indicator without a delivery rationale.

* **Stability and storage:** Proteins are heat- and oxidation-sensitive. Reputable products use protective packaging (opaque, air-restricting) and may recommend refrigeration; check for stabilizers and avoid products with no stability provisions or that have been exposed to heat.

* **Third-party testing and manufacturer credibility:** Prefer formulations from manufacturers that disclose sourcing, provide batch consistency, and ideally offer third-party verification of identity and purity; growth-factor ingredients vary widely in quality, and marketing claims often outrun verified content.

* **Reputable formulators:** Cosmetic-science-oriented brands that publish ingredient rationales (e.g., those using established CG-aFGF/peptide complexes) and compounding-grade suppliers are preferable to anonymous marketplace serums with unverifiable claims.

## Practical Considerations

* **Time to effect:** Hair cycles are slow; any visible change would be expected over months, not weeks. By analogy to peptide and growth-factor hair-serum studies, meaningful assessment typically occurs at roughly 12 and 24 weeks of consistent use, and results should not be judged before about three months.

* **Common pitfalls:** Frequent mistakes include expecting drug-level results from a cosmetic, judging too early, using a product with no credible delivery system, applying inconsistently, and assuming a growth-factor serum can replace established treatments (minoxidil, finasteride) rather than complement them.

* **Regulatory status:** In the United States and most markets, Sh-Polypeptide-11 is sold as a cosmetic ingredient, not an approved drug for hair regrowth; it is not FDA-approved to treat androgenetic alopecia, and hair-growth claims for cosmetics are not held to drug-level evidence standards. Recombinant acidic FGF has separately been studied as a medical wound-healing agent in some countries.

* **Cost and accessibility:** Growth-factor serums are typically positioned at the premium end of the hair-care market and can be considerably more expensive than generic minoxidil, which is relevant given the limited efficacy evidence; accessibility is otherwise good as an over-the-counter cosmetic.

## Interaction with Foundational Habits

* **Sleep:** The interaction is indirect/none. There is no known mechanism by which a topically applied, poorly absorbed scalp protein affects sleep, and no evidence that sleep timing alters its local action. Sleep supports overall hair health generally, but no specific practical timing consideration applies to this peptide.

* **Nutrition:** The interaction is indirect. Sh-Polypeptide-11 does not deplete nutrients or require a specific diet. However, follicle response to any pro-growth signal depends on adequate substrate; correcting deficiencies relevant to hair (notably iron/ferritin, protein, and overall caloric adequacy) plausibly supports any benefit, while no food needs to be avoided around topical use.

* **Exercise:** The interaction is largely none/indirect. Exercise does not blunt or potentiate a topical scalp peptide in any established way. A practical consideration is timing relative to sweating: applying the serum after exercise and scalp washing (rather than before heavy sweating) avoids dilution or premature removal.

* **Stress management:** The interaction is indirect. High chronic stress can push follicles toward shedding (telogen effluvium) and may counteract a pro-growth signal; managing stress addresses an upstream driver of hair loss rather than interacting with the peptide directly. No effect of this topical on cortisol or the stress response is described.

## Monitoring Protocol & Defining Success

Because Sh-Polypeptide-11 is a topical cosmetic with minimal systemic absorption, formal laboratory monitoring is not required for the ingredient itself. The most useful monitoring is structured assessment of the hair response and of any underlying, treatable drivers of hair loss. Baseline evaluation before starting establishes a reference point (standardized scalp photographs, hair density/diameter, and a baseline check of common reversible contributors). Where labs are used, they target underlying causes of hair loss rather than effects of the peptide.

The lab tests below are optional and aimed at identifying correctable contributors to hair loss before attributing success or failure to the serum. A reasonable cadence is to obtain any relevant baseline labs once before starting, then re-test only if clinically indicated; objective hair assessment (photographs, density) is most useful at baseline, then at roughly 12 weeks, 24 weeks, and every 6 months thereafter.

| Biomarker | Optimal Functional Range | Why Measure It? | Context/Notes |
| --- | --- | --- | --- |
| Ferritin (iron stores) | 50–70+ ng/mL | Low iron stores are a common, reversible driver of hair shedding | Conventional "normal" starts ~15–30 ng/mL, well below the functional hair threshold; fasting not required |
| TSH (thyroid-stimulating hormone) | ~0.5–2.5 mIU/L | Thyroid imbalance is a frequent treatable cause of diffuse hair loss | Conventional upper limit (~4.0–4.5) is higher than the functional target; best paired with free T4 |
| Vitamin D (25-hydroxyvitamin D) | 40–60 ng/mL | Low vitamin D is associated with hair-cycle disruption | Conventional "sufficient" starts at 30 ng/mL; no fasting needed |
| Total testosterone & DHEA-S | Sex- and age-appropriate optimal range | Androgen excess (especially in women) signals an androgen-driven component that a growth factor will not address | Best drawn in the morning; abnormal results warrant evaluation of the primary driver |
| Zinc | Upper half of reference range | Zinc deficiency can contribute to hair loss and impaired follicle function | Often paired with ferritin and vitamin D; trace-element handling matters for sample quality |

Qualitative markers are often more informative than labs for tracking a cosmetic hair serum:

* Reduced daily shedding (e.g., fewer hairs in the brush, shower, or on the pillow)
* Increase in fine "regrowth" hairs along the hairline or part, then their thickening into coarser hairs over months
* Subjective scalp coverage, part width, and ponytail thickness
* Overall scalp comfort and absence of irritation as a tolerability marker

Success is best defined conservatively for this ingredient: stabilization of shedding and modest visible improvement in density/coverage over 3–6 months on standardized photographs, with good tolerability — recognizing that strong regrowth comparable to established drugs should not be the default expectation.

## Emerging Research

* **Peptide-factor hair serum vs. minoxidil (active trial):** A randomized, double-blind trial ([NCT07536100](https://clinicaltrials.gov/study/NCT07536100)) is comparing a peptide-factor hair serum against 2% topical minoxidil in 80 adults with androgenetic alopecia over 24 weeks, with hair density and diameter as endpoints. It is the closest registered test of the growth-factor/peptide-serum approach this ingredient belongs to, and could either strengthen or weaken the case depending on whether peptide serums match minoxidil.

* **FGF-pathway hair biology (recent review):** A 2025 review of fibroblast growth factors in hair-follicle growth ([Wang et al., 2025](https://pubmed.ncbi.nlm.nih.gov/40867641/)) argues the FGF/FGFR pathway is a promising and underexplored therapeutic target that could exceed current treatments, while flagging how much human follicle receptor biology is still unknown — a direction that could strengthen the rationale if translated.

* **Mechanistic anagen-induction evidence (foundational):** The key animal finding that FGFs, including acidic FGF, induce anagen via β-catenin and Sonic hedgehog ([Lin et al., 2015](https://pubmed.ncbi.nlm.nih.gov/25685806/)) remains the strongest pro-hair signal; replication and, critically, translation to controlled human scalp studies is the research most likely to change current understanding.

* **Follicle-protection direction (counter/complementary evidence):** Work showing acidic FGF reduces follicle-cell death under stress ([Nakayama et al., 2009](https://pubmed.ncbi.nlm.nih.gov/19469896/)) points toward a protective rather than purely regrowth role; whether this protective effect occurs in human androgenetic loss is an open question that could broaden or narrow the indication.

* **Cosmetic-peptide evidence appraisal (skeptical direction):** A 2025 review of topical hair-loss actives ([Bikash, 2025](https://pubmed.ncbi.nlm.nih.gov/40654553/)) catalogs the limited, conflict-of-interest-prone evidence behind hyped cosmetic hair peptides and argues they are best seen as add-ons; this line of work could weaken standalone claims for growth-factor serums if rigorous comparative trials remain absent.

## Conclusion

Sh-Polypeptide-11 is a lab-made copy of a natural human growth signal (acidic fibroblast growth factor) added to topical scalp and skin serums. The idea behind it is biologically reasonable: this signal pushes resting hair follicles toward active growth and supports the cells and blood vessels around them. In laboratory and animal studies, this family of growth signals did reawaken dormant follicles and lengthen the active growth phase, and one related effect may help protect follicles from stress-related loss.

The gap is in human proof. There are no published, controlled human studies showing that this specific ingredient regrows scalp hair, so its main benefits remain promising rather than demonstrated. The same signaling family also contains an opposing factor that ends hair growth, and the protein is large and hard to absorb through skin, so results depend heavily on the product's delivery system. On safety, topical use appears generally well tolerated, with mild local irritation the most likely issue and only theoretical concerns beyond that.

Overall, the evidence base is thin and leans on mechanism and animal work rather than human outcomes, and several sources promoting it have a commercial interest. It is best understood as an early-stage, plausible add-on whose real-world effect on human hair is not yet established.

**[Top](#top) - [Benefits](#expected-benefits) - [Risks](#potential-risks--side-effects) - [Protocol](#therapeutic-protocol)**


---
canonical_name: Sh-Polypeptide-1
alternate_names: Recombinant Human Basic Fibroblast Growth Factor, rh-bFGF, bFGF, FGF-2, FGF2, sh-Polypeptide-1, sh-bFGF
canonical_topic: Sh-Polypeptide-1 for Hair Regrowth
short_topic_lc: sh_polypeptide_1_hair
creation_date: 2026-0628-0005
creator_ai_fullname: Opus 4.8
---

# Sh-Polypeptide-1 for Hair Regrowth

Evidence Review created on 06/28/2026 using [AI4L](https://github.com/forever-healthy/AI4L) / Opus 4.8

**Also known as:** Recombinant Human Basic Fibroblast Growth Factor, rh-bFGF, bFGF, FGF-2, FGF2, sh-Polypeptide-1, sh-bFGF

## Motivation

Sh-Polypeptide-1 is the cosmetic-ingredient name for a laboratory-made copy of basic fibroblast growth factor, a natural messenger protein the body uses to tell skin and connective-tissue cells to multiply and to build new blood vessels. Around the scalp follicle, this signal supports the cells at the base of the hair and the local blood supply, helping push a resting hair into its active growing phase. Because of this role, it appears in topical scalp serums marketed for thinning hair.

Interest in this protein grew from decades of laboratory work showing it is one of the most studied signals for cell growth and blood-vessel formation, and from animal studies in which fibroblast growth factors triggered earlier and longer hair growth. A purified form of the same protein is used in some countries as a medicine to heal skin wounds, establishing a track record on living skin.

This review examines what is known about applying Sh-Polypeptide-1 to the scalp for hair regrowth. It surveys the underlying biology, the animal and human findings, the gap between strong laboratory signals and limited human testing, and the practical questions of how such a delicate protein is delivered, sourced, and combined with established hair treatments.

**[Benefits](#expected-benefits) - [Risks](#potential-risks--side-effects) - [Protocol](#therapeutic-protocol) - [Conclusion](#conclusion)**

## Recommended Reading

This section lists high-level overviews and expert commentary that discuss basic fibroblast growth factor and its role in hair biology in substantial depth.

* [Sh-Polypeptide-1](https://www.stratiaskin.com/blogs/ingredients/sh-polypeptide-1) - Stratia

  An ingredient-glossary explainer that directly identifies Sh-Polypeptide-1 as basic fibroblast growth factor, describes how it stimulates fibroblasts and skin regeneration, and frames why this growth-factor peptide is used in cosmetic formulations. It is the clearest entry point for confirming what this ingredient actually is.

* [Basic Fibroblast Growth Factor for Hair Loss](https://www.rejuvenceclinic.co.uk/basic-fibroblast-growth-factor-for-hair-loss/) - Rejuvence Clinic

  A clinic-authored overview explaining what basic fibroblast growth factor (the protein behind Sh-Polypeptide-1) is, how it is positioned for hair loss in topical and in-clinic treatments, and the practical considerations of delivering a recombinant protein to the scalp.

* [Fibroblast Growth Factor Effective in Treating Thinning Hair](https://www.belgraviacentre.com/blog/fibroblast-growth-factor-effective-in-treating-thinning-hair) - Mike Peake

  A hair-loss clinic commentary that explains how basic fibroblast growth factor (FGF-2, the protein behind Sh-Polypeptide-1) has been studied for thinning hair, summarizing a human scalp study using topical FGF-2 nanoparticles and situating the growth factor among emerging follicle-stimulating approaches.

*Note: Fewer than 5 items are listed because Sh-Polypeptide-1 (basic fibroblast growth factor) for hair is a narrow cosmetic-peptide topic with very little eligible high-level coverage. Systematic reviews, meta-analyses, encyclopedias, and product/retailer pages are excluded per the section rules, which removes most of the available material. None of the priority experts (Rhonda Patrick, Peter Attia, Andrew Huberman, Chris Kresser, Life Extension) have published content on this intervention by name. The list has not been padded with marginally relevant content.*

## Grokipedia

* [Fibroblast growth factor 2](https://grokipedia.com/page/fibroblast_growth_factor_2) - Grokipedia

  The Grokipedia entry covers the protein's molecular identity (FGF2, also called basic fibroblast growth factor, the molecule behind Sh-Polypeptide-1), its receptor signaling, and its documented functions in cell growth, angiogenesis, and skin biology, providing useful background context for the cosmetic peptide.

## Examine

No Examine.com article exists for Sh-Polypeptide-1 (basic fibroblast growth factor). Examine.com focuses on ingestible dietary supplements and does not typically cover topical cosmetic peptides or recombinant protein actives.

## ConsumerLab

No ConsumerLab.com article exists for Sh-Polypeptide-1 (basic fibroblast growth factor). ConsumerLab tests and reviews ingestible supplements and does not typically cover topical cosmetic peptide actives.

## Systematic Reviews

This section lists systematic reviews and meta-analyses relevant to basic fibroblast growth factor and related growth-factor approaches to hair.

* [Regenerative medicine in the treatment of specific dermatologic disorders: a systematic review of randomized controlled clinical trials](https://pubmed.ncbi.nlm.nih.gov/38886861/) - Jafarzadeh et al., 2024

  A systematic review of 64 randomized controlled trials (RCTs, studies that randomly assign participants to treatment or control to reduce bias) covering 2,888 patients across dermatologic conditions, with androgenetic alopecia (the most common pattern hair loss, driven by hormones and genetics) the most studied. It situates growth-factor-based regenerative methods among hair treatments but does not isolate basic fibroblast growth factor as a single agent, underscoring how little direct trial evidence exists for this specific protein.

## Mechanism of Action

Sh-Polypeptide-1 is the cosmetic-ingredient (INCI, the standardized naming system for ingredients on cosmetic labels) name for recombinant (laboratory-produced) basic fibroblast growth factor (bFGF), also called fibroblast growth factor 2 (FGF-2), a roughly 17–18-kilodalton protein in the fibroblast growth factor family. Unlike a tissue-restricted signal, bFGF is a broad mitogen (cell-multiplication signal) that acts on many cell types — fibroblasts (connective-tissue cells), keratinocytes (skin and follicle-lining cells), and the endothelial cells that line blood vessels.

In the hair follicle, bFGF is expressed in the hair matrix and around the dermal papilla (the signaling hub at the follicle base) and signals mainly through the receptor FGFR1 (fibroblast growth factor receptor 1, a docking protein on responsive cells). Receptor binding activates several growth-promoting cascades: MAPK/ERK (a core cell-division pathway), PI3K/Akt (a cell-survival pathway), and Wnt/β-catenin (a master switch for follicle activation). The net effects are proliferation of dermal papilla cells, increased blood-vessel supply to the follicle, and a push of resting follicles into the growing (anagen) phase.

Animal work defines its role: in mice, topically applied fibroblast growth factors, including bFGF, induced an earlier anagen phase and prolonged active growth, acting through β-catenin and Sonic hedgehog (Shh, a follicle-patterning signal) to stimulate hair growth. bFGF promotes the angiogenesis (new blood-vessel formation) and dermal papilla activity that sustain a growing follicle rather than acting primarily on the hair shaft's keratin structure.

A competing mechanistic view tempers expectations: bFGF is one of several partly redundant follicle growth factors, working alongside insulin-like growth factor 1 (IGF-1, a growth and repair hormone) and vascular endothelial growth factor (VEGF, which drives blood-vessel supply), and within the FGF family it is not the most potent for hair (FGF-7 and FGF-10 show stronger follicle effects in some models). This redundancy may explain why isolated topical use produces weaker effects than the laboratory signal predicts.

Pharmacologically, bFGF is a hydrophilic (water-loving) protein that is degraded by normal protein breakdown rather than by liver enzymes such as CYP3A4 (a major drug-metabolizing enzyme), so classic small-molecule drug-interaction concerns do not apply; it is also heat- and acid-labile, losing activity quickly outside a stabilized formulation. Its size and instability make passive penetration through intact skin poor, the central delivery challenge for any scalp formulation.

## Historical Context & Evolution

Basic fibroblast growth factor was identified in the 1970s–1980s as one of the first growth factors purified, recognized for powerfully stimulating fibroblast and blood-vessel cell growth, and through the following decades its role in wound healing and skin biology was mapped. The original intended use was never cosmetic: researchers pursued it as a tissue-repair and regenerative agent for damaged skin.

A major clinical translation was wound care. A recombinant form (trafermin) was developed and approved in some countries to accelerate healing of skin ulcers and wounds, applied directly to the affected skin. This established a manufacturing route and a human track record for the protein acting on living tissue.

The move toward hair came from animal research on fibroblast growth factors. Foundational work showed that members of the FGF family, including bFGF, influence the hair-growth cycle, and that topical fibroblast growth factors could induce an earlier and longer growing phase in mice, framing bFGF as one of several naturally occurring mediators of follicle activity. These findings, combined with the protein's strong effects on dermal cells and blood-vessel supply, motivated interest in using it to support scalp hair.

The evolution of opinion has been cautious rather than settled. Early enthusiasm rested on strong laboratory and animal signals. As cosmetic use spread, rigorous human testing remained scarce, and questions were raised about whether a delicate protein applied to intact skin can reach and act on follicles at all. The current standing is that the biology is well supported while direct human efficacy for regrowth remains largely unproven; what is unsettled is not the mechanism but whether the protein can be delivered to active follicles and shown to produce a clinical effect.

## Expected Benefits

A dedicated search across PubMed, clinical sources, and expert reviews was performed for the complete benefit profile of basic fibroblast growth factor in hair before writing this section. The benefits below reflect the target audience of risk-aware adults considering this peptide as part of a hair-optimization strategy, not population-level outcomes.

### High 🟩 🟩 🟩

(No benefits qualify for the High evidence level. No adequately powered human randomized controlled trials demonstrate that topical Sh-Polypeptide-1 regrows scalp hair, so no benefit reaches this grade.)

### Medium 🟩 🟩

(No benefits qualify for the Medium evidence level.)

### Low 🟩

#### Promotion of the Hair Growth (Anagen) Phase

In animal models, topically applied basic fibroblast growth factor drives resting follicles into the active growing phase, stimulating dermal papilla cell proliferation through FGFR1 signaling and acting via the β-catenin and Sonic hedgehog pathways. The evidence basis is in vivo animal studies, including induction of an earlier and prolonged anagen phase in mice, supported by mechanistic work showing dermal papilla activation. The benefit is graded Low because it has not been demonstrated in controlled human scalp trials and depends on the protein reaching live follicle cells, which topical delivery does not reliably achieve.

**Magnitude:** In mouse models, topical fibroblast growth factors including bFGF accelerated entry into anagen and extended the growth phase; no validated human regrowth percentage exists for topical bFGF.

#### Improved Follicle Blood Supply (Angiogenesis)

Basic fibroblast growth factor is a potent driver of angiogenesis (new blood-vessel formation), and a denser blood supply around the follicle supports the nutrient and oxygen delivery that a growing hair requires. The evidence basis is the well-established pro-angiogenic action of bFGF on endothelial cells in animal and laboratory studies, with vascularization being a recognized contributor to the anagen environment. It is graded Low because, although the angiogenic effect itself is robust, a resulting hair-density benefit in humans from a topically applied protein has not been demonstrated.

**Magnitude:** Not quantified in available studies.

### Speculative 🟨

#### Support of Hair Density When Combined with Other Actives

Cosmetic scalp serums pair Sh-Polypeptide-1 with other growth factors and peptides, and laboratory work shows basic fibroblast growth factor acts together with IGF-1 (a growth and repair hormone) and VEGF (which builds the follicle's blood supply) to sustain follicle cell growth and nutrient delivery. No controlled human study isolates the contribution of Sh-Polypeptide-1 within these blends, so any added density benefit rests on mechanism and product-level marketing rather than direct evidence; the basis is mechanistic and anecdotal only. A conflict of interest should be noted here and throughout: almost all of the hair-specific evidence is produced by parties with a direct financial stake in adoption — cosmetic ingredient suppliers and serum manufacturers, and the few human scalp trials are industry-sponsored (e.g., Schweitzer Biotech-collaborated studies in the Emerging Research section) — so favorable framing must be weighed against that commercial interest.

#### Improvement in Hair-Shaft Quality and Caliber

Because basic fibroblast growth factor stimulates dermal papilla cells, which govern the size of the hair bulb and therefore shaft thickness, it is proposed that supplying it could improve the caliber and quality of individual hair shafts rather than only follicle count. This remains speculative for topical human use: no human study measures shaft caliber after Sh-Polypeptide-1 application, and the basis is extrapolation from animal and cell-culture biology only.

## Benefit-Modifying Factors

The following factors may influence how much benefit, if any, a person derives from Sh-Polypeptide-1.

* **Delivery method and follicle access:** Because basic fibroblast growth factor is a delicate, water-loving protein that penetrates intact skin poorly, the single biggest modifier of benefit is whether it reaches living follicle cells. Microneedling, fractional lasers, or other barrier-disrupting steps that accompany application are likely to determine whether any effect occurs at all.

* **Genetic polymorphisms:** No pharmacogenetic variants are established to predict benefit from topical basic fibroblast growth factor. In principle, germline variants affecting FGFR1 signaling (the receptor through which bFGF activates follicle cells) could alter how strongly a follicle responds, so individuals with a more responsive receptor profile might in theory derive greater benefit, but no clinical evidence supports this and it remains hypothetical.

* **Baseline follicle viability:** The protein acts on living follicle epithelium, so scalps with miniaturized but still-living follicles (early-stage thinning) are more plausible responders than areas of long-standing baldness where follicles are fibrosed and gone. Baseline density and the proportion of dormant-but-alive follicles modify the realistic ceiling of benefit.

* **Baseline biomarker levels:** Although no biomarker predicts response to the protein directly, baseline nutritional and hormonal markers set the follicle environment any growth factor acts within. Suboptimal baseline ferritin (iron stores), vitamin D, zinc, or thyroid status independently drives shedding and can cap or mask any benefit, so a person starting with deficient baseline values is a less plausible responder until those values are corrected.

* **Concurrent growth-factor and hormonal milieu:** bFGF works alongside IGF-1 and VEGF, so local levels of these signals — influenced by scalp blood flow, age, and co-administered actives — may modify response. In hormone-driven (androgenetic) hair loss, the underlying androgen signal is not addressed by bFGF, limiting standalone benefit.

* **Sex-based differences:** No human data establish a sex difference in response to topical basic fibroblast growth factor for hair. Because the dominant driver of pattern hair loss differs by sex (androgens in men, more mixed in women) and bFGF does not act on that pathway, the practical value as a sole agent may differ, but this is inferred rather than measured.

* **Age-related considerations:** Follicle regenerative capacity and dermal-papilla signaling decline with age, including at the older end of the health-and-longevity target range. Older follicles may respond less to a proliferative signal, and age-related thinning of the scalp barrier could marginally alter penetration, though neither effect is quantified for this protein.

## Potential Risks & Side Effects

A dedicated search of drug-reference sources (medical bFGF/trafermin product information, drugs.com, clinical literature) and cosmetic-ingredient safety data was performed for the complete side-effect profile before writing this section. Risks are framed for risk-aware adults using a topical scalp product; the medical wound-care form, applied directly to compromised skin, informs the upper bound of biological concern.

### High 🟥 🟥 🟥

(No risks qualify for the High evidence level for topical cosmetic use. There are no controlled human safety data for topical Sh-Polypeptide-1 on the scalp that establish a high-frequency adverse effect.)

### Medium 🟥 🟥

(No risks qualify for the Medium evidence level for topical cosmetic use.)

### Low 🟥

#### Local Skin and Scalp Irritation

As with most topical cosmetic actives and peptide serums, the most plausible adverse effects are application-site reactions: redness, itching, stinging, or contact irritation, which may be driven as much by the formulation's solvents, preservatives, and penetration enhancers as by the protein itself. The evidence basis is the general behavior of topical cosmetic serums and the absence of reported serious local toxicity; severity is typically mild and reversible on discontinuation. It is graded Low because dedicated controlled safety data for this specific scalp peptide are lacking.

**Magnitude:** Not quantified in available studies.

#### Local Effects Known from the Medical Use of bFGF

In its medical form, recombinant basic fibroblast growth factor (marketed in some countries as trafermin for ulcers and wounds) is applied to compromised skin and can cause application-site reactions such as irritation, redness, and itching, reflecting the protein's strong action on skin and connective tissue. These effects follow direct application to broken skin at therapeutic doses, so they bound the theoretical concern rather than describing expected cosmetic events; they are graded Low for intact-scalp use because meaningful absorption through unbroken skin is unlikely.

**Magnitude:** With medical bFGF applied to wounds, local reactions occur in a minority of treated cases; intact-scalp cosmetic exposure is expected to be substantially lower.

### Speculative 🟨

#### Theoretical Stimulation of Unwanted Cell Growth

Because basic fibroblast growth factor is a potent driver of cell proliferation and new blood-vessel formation, and the FGF/FGFR pathway is implicated in some cancers, there is a theoretical concern that strong, sustained local stimulation could promote unwanted growth of skin or vascular tissue. This is speculative for cosmetic topical use: no human evidence links topical basic fibroblast growth factor serums to skin tumors, and poor penetration limits exposure; the basis is mechanistic reasoning and pathway biology only.

#### Effects from Compromised Skin-Barrier Application

If Sh-Polypeptide-1 is deliberately driven into the skin via microneedling or laser channels to overcome its poor penetration, the same breach raises the speculative possibility of infection, deeper irritation, or unintended growth-factor activity in the dermis. No controlled data characterize this combined-use risk; the basis is the known hazards of barrier-disruption procedures combined with an active growth factor, reported only anecdotally.

## Risk-Modifying Factors

The following factors may influence the likelihood or severity of adverse effects from Sh-Polypeptide-1.

* **Genetic polymorphisms:** No pharmacogenetic variants are established for topical basic fibroblast growth factor. In principle, individuals with germline variants affecting FGFR signaling could theoretically respond differently, but no clinical evidence supports screening, and this remains hypothetical.

* **Baseline biomarker levels:** For topical cosmetic use there are no baseline biomarkers that predict risk from basic fibroblast growth factor. No routine laboratory value is established to screen for or monitor risk from a poorly absorbed topical protein, so this factor is not applicable to low-exposure scalp application.

* **Sex-based differences:** No sex-based difference in the risk or side-effect profile of topical basic fibroblast growth factor has been documented. Reported reactions to the medical wound-care form do not show a clear sex skew.

* **Pre-existing health conditions:** A personal history of skin cancer or pre-cancerous scalp lesions is the most relevant condition, given the protein's pro-proliferative action; caution is reasonable even though no causal link is established. Active scalp infection, inflammation, or open wounds would increase irritation and absorption risk.

* **Age-related considerations:** Older skin, including at the upper end of the target age range, may have a more fragile barrier and slower healing, modestly increasing the chance of irritation when penetration-enhancing methods are used. Age does not alter the protein's intrinsic safety profile in any documented way.

## Key Interactions & Contraindications

Interaction data are derived chiefly from the injected approved protein and from general principles, because no formal interaction studies exist for topical Sh-Polypeptide-1.

* **Active malignancy or concurrent cancer therapy:** Because basic fibroblast growth factor is a potent driver of cell proliferation and new blood-vessel formation, applying it over or near an active or recent skin cancer raises a theoretical concern of supporting unwanted growth, and its biology could in principle interfere with anticancer treatment. Severity: caution. Clinical consequence: theoretical stimulation of malignant or pre-malignant tissue. Mitigating action: avoid use over suspicious lesions and during active cancer treatment without oncology guidance.

* **Topical scalp irritants and retinoids:** Combining the serum with strong topical irritants such as retinoids (vitamin A derivatives that increase cell turnover) or high-strength exfoliating acids may compound irritation and barrier disruption. Severity: caution. Clinical consequence: increased redness and stinging. Mitigating action: separate application times or alternate days.

* **Minoxidil and other topical hair actives:** No documented harmful interaction exists with minoxidil (a vasodilator-derived topical hair-growth drug); it is often layered in the same routine and the combination is plausibly additive. Severity: monitor. Clinical consequence: additive scalp irritation at most. Mitigating action: introduce one product at a time to attribute any reaction.

* **Microneedling and energy-based devices:** Microneedling, fractional lasers, and radiofrequency devices are used specifically to enhance penetration of the protein. Severity: caution. Clinical consequence: greater absorption and irritation, theoretical deeper growth-factor activity. Mitigating action: use sterile technique, conservative depth, and avoid on infected or inflamed skin.

* **Over-the-counter products and supplements:** No specific over-the-counter medication or oral supplement interaction is established for topical basic fibroblast growth factor; oral supplements are not expected to interact with a poorly absorbed topical protein. Supplements marketed alongside it for hair (biotin, collagen peptides) have no documented additive or antagonistic effect with this protein.

* **Populations who should avoid it:** People with a current or recent scalp skin cancer or pre-cancerous lesions, active scalp infection or open wounds, and those undergoing active chemotherapy or radiation (without oncology direction) should avoid use. Pregnant and breastfeeding individuals should avoid it given the complete absence of safety data, even though topical absorption is expected to be minimal.

## Risk Mitigation Strategies

The following practical strategies address the specific risks identified above and are actionable by the target audience.

* **Patch test before full scalp use:** Apply a small amount to a discreet area for several days before regular use to detect irritation or allergic reaction early, mitigating the risk of widespread application-site irritation.

* **Start with low frequency and build up:** Begin with application every other day rather than twice daily for the first 1–2 weeks, increasing only if well tolerated, to mitigate cumulative scalp irritation from the serum and its excipients.

* **Avoid layering with strong irritants:** Separate the serum from retinoids and exfoliating acids by at least several hours, or alternate days, to prevent compounded barrier disruption and stinging.

* **Use conservative technique with penetration enhancers:** If pairing with microneedling, keep needle depth modest (commonly 0.5–1.0 mm for scalp), sterilize the device, and avoid broken or infected skin, mitigating infection and deep-irritation risk created by deliberately breaching the barrier.

* **Screen the scalp for suspicious lesions first:** Before starting, have any new, changing, or non-healing scalp lesions evaluated, and avoid applying a pro-proliferative growth factor over them, mitigating the theoretical risk of stimulating unwanted epithelial growth.

* **Discontinue and reassess on persistent reaction:** Stop use if redness, itching, or stinging lasts beyond a few days, since most application-site reactions reverse on discontinuation; this prevents a mild local reaction from progressing.

## Therapeutic Protocol

No standardized, evidence-based dosing protocol for Sh-Polypeptide-1 exists, because human regrowth trials are lacking. The following reflects how cosmetic and integrative practitioners typically use basic fibroblast growth factor scalp products.

* **Standard topical use as practiced:** Practitioners and product instructions typically direct applying a few drops of a growth-factor scalp serum to clean, dry, thinning areas once or twice daily, massaged in and left on. Sh-Polypeptide-1 is almost always one component of a multi-growth-factor blend rather than a standalone product.

* **Conventional vs. enhanced-delivery approaches:** Two main approaches coexist without one being the established default. The conventional approach is simple topical application, accepting low penetration. The enhanced-delivery approach combines the serum with microneedling or fractional laser on a periodic schedule (often weekly to monthly) to drive the protein into the skin; clinics offering growth-factor "hair restoration" protocols popularized this method.

* **In-clinic growth-factor protocols:** Aesthetic and hair-restoration clinics that popularized growth-factor scalp treatments typically combine topical or injected growth-factor preparations with microneedling sessions spaced weeks apart, sometimes alongside platelet-rich plasma; these are practitioner-driven protocols rather than products with published dosing.

* **Best time of day:** No circadian or time-of-day advantage is established for topical basic fibroblast growth factor. Timing is driven by routine convenience and by separating it from other irritating topicals rather than by the protein's biology.

* **Half-life consideration:** Like other growth-factor proteins, basic fibroblast growth factor has a short circulating half-life when given systemically, but for a leave-on topical the relevant factor is residence time on and in the skin, not blood half-life; the protein's stability in the formulation matters more than its systemic clearance.

* **Single vs. split application:** Because the limiting factor is penetration rather than dose saturation, splitting into morning and evening applications is common to maintain contact time, but no comparative data show split dosing outperforms once-daily use.

* **Genetic polymorphisms:** No pharmacogenetic variants (such as those affecting drug-metabolizing enzymes) are known to guide dosing of this topical protein, since it is not metabolized by the liver enzyme systems relevant to small-molecule drugs.

* **Sex-based differences in response:** No sex-specific dosing is established. Because the protein does not act on the androgen pathway central to male pattern loss, men relying on it alone may see less effect, an inference rather than a measured dosing difference.

* **Age-related considerations:** Older users, including at the upper end of the target range, have less regenerative follicle capacity, so realistic expectations and longer trial periods are warranted, though no age-adjusted dose exists.

* **Baseline biomarker levels:** No baseline laboratory value guides topical dosing; assessment is clinical (degree and pattern of thinning) rather than biochemical.

* **Pre-existing conditions influencing response:** Early, active thinning with viable follicles is the scenario most likely to respond; long-standing baldness with lost follicles is unlikely to respond regardless of dose.

## Discontinuation & Cycling

* **Lifelong vs. short-term use:** Like other cosmetic hair actives, any benefit depends on continued use; basic fibroblast growth factor is a transient proliferative signal, not a permanent change to follicle programming, so stopping is expected to let hair revert toward its untreated trajectory. There is no defined treatment course because efficacy itself is unproven.

* **Withdrawal effects:** No withdrawal syndrome or rebound shedding specific to topical basic fibroblast growth factor has been documented. Any apparent shedding after stopping would reflect loss of a maintenance effect rather than a true withdrawal reaction.

* **Tapering:** No tapering protocol is needed or established; because there is no dependence or rebound documented, the product can be stopped abruptly without a known adverse consequence.

* **Cycling:** No evidence supports cycling on and off to maintain efficacy. Cycling is sometimes proposed generically for growth factors on the theory of avoiding receptor downregulation, but this is speculative for basic fibroblast growth factor and unsupported by data.

## Sourcing and Quality

* **Recombinant source and form:** Sh-Polypeptide-1 in cosmetics is a recombinant protein, typically produced in bacterial (*E. coli*) or yeast expression systems. Buyers should look for products that specify it is the human basic fibroblast growth factor sequence and that disclose concentration, since "growth factor" labeling alone is uninformative.

* **Protein stability and formulation:** Growth-factor proteins are fragile and lose activity with heat, light, and time, so formulation and storage matter more than for small-molecule actives. What to look for: cold-chain or refrigerated products, opaque or air-restricting packaging, stated shelf life, and reconstitute-before-use (lyophilized) formats that improve stability.

* **Third-party testing:** Because this is a cosmetic rather than a regulated drug, independent verification of identity, concentration, and bioactivity is rarely available; preference should go to manufacturers that publish certificates of analysis or third-party activity assays, as label claims are otherwise unverifiable.

* **Reputable sources:** Cosmetic ingredient suppliers and formulators that serve the professional skincare market, and specialty manufacturers of the medical recombinant protein, are more reliable than unbranded peptide vendors. Research-grade "bFGF peptide" sold by chemical suppliers is not formulated or tested for human cosmetic use and should not be substituted.

## Practical Considerations

* **Time to effect:** No reliable human timeline exists. By analogy to other hair actives that act on the growth cycle, any visible change would plausibly take 3–6 months of consistent use, and the absence of change at that point would suggest non-response given the delivery limitations.

* **Common pitfalls:** The most common mistakes are expecting a delicate protein to work through intact skin without any penetration enhancement, judging results before several months, and assuming Sh-Polypeptide-1 alone addresses hormone-driven pattern loss, which it does not. Confusing research-grade peptide powder with a formulated cosmetic is another frequent error.

* **Regulatory status:** As a topical cosmetic ingredient, Sh-Polypeptide-1 is not approved by the FDA as a drug for hair regrowth, and marketing it for regrowth is an off-label/unsubstantiated claim. A recombinant medical form of basic fibroblast growth factor (trafermin) is approved in some countries (e.g., Japan) for skin wounds and ulcers, not for hair, and it is not FDA-approved as a drug.

* **Cost and accessibility:** Growth-factor scalp serums are typically expensive relative to minoxidil and require ongoing repurchase, and quality products may need refrigeration and careful handling. Accessibility is otherwise straightforward through cosmetic channels, but verified, potent products are harder to find than the many low-disclosure offerings.

## Interaction with Foundational Habits

* **Sleep:** The interaction is indirect with no documented direction specific to basic fibroblast growth factor. There is no evidence that the topical protein affects sleep or that sleep alters its action; the practical consideration is only that consistent routines aid adherence.

* **Nutrition:** The interaction is indirect. Adequate protein and micronutrient status (iron, zinc, vitamin D) supports the follicle environment that any growth factor acts within, so deficiencies could blunt benefit; no specific diet potentiates the topical protein, and it does not deplete nutrients.

* **Exercise:** The interaction is indirect and potentiating at most. Exercise increases scalp blood flow, which supports follicle nutrient delivery alongside the VEGF-related effects of the growth-factor pathway; there is no evidence exercise blunts the protein, and no timing relationship around workouts is established. Sweating heavily right after application could reduce contact time, a minor practical consideration.

* **Stress management:** The interaction is indirect. Chronic stress can push follicles into shedding (telogen effluvium) through cortisol and inflammatory signaling, working against the growth-promoting goal; managing stress supports the follicle cycle the protein targets, but there is no direct mechanistic interaction with basic fibroblast growth factor itself.

## Monitoring Protocol & Defining Success

For a topical cosmetic peptide with minimal systemic absorption, laboratory monitoring is generally not required; the most useful monitoring is structured visual tracking of the scalp. Baseline assessment should be done before starting, and progress reviewed at defined intervals.

Baseline assessment is primarily visual and clinical: standardized scalp photographs in consistent lighting, a record of the thinning pattern, and optionally a clinician's hair-density measurement. The lab tests below are relevant mainly to rule out reversible contributors to hair loss before attributing results to the peptide, not to monitor the peptide itself.

Ongoing monitoring is photographic and qualitative rather than laboratory-based, reviewed at baseline, 3 months, and 6 months, then every 6 months thereafter to judge whether continued use is justified.

| Biomarker | Optimal Functional Range | Why Measure It? | Context/Notes |
|---|---|---|---|
| Ferritin (iron stores) | 50–100 ng/mL | Low iron stores drive diffuse hair shedding and blunt regrowth | Conventional lab range starts near 15 ng/mL, far below the functional hair threshold; fasting not required |
| Vitamin D (25-hydroxy) | 40–60 ng/mL | Deficiency is linked to hair-cycle disruption | Conventional "sufficient" begins at 30 ng/mL; pair with calcium awareness if supplementing |
| TSH | 1.0–2.0 mIU/L | Thyroid imbalance causes reversible hair loss that can confound results | TSH is thyroid-stimulating hormone (the pituitary signal controlling thyroid output); conventional range extends to ~4.5 mIU/L; best drawn in the morning |
| Free testosterone & DHEA-S | Sex- and age-appropriate optimal range | Androgen excess underlies pattern loss this peptide does not address | DHEA-S is dehydroepiandrosterone sulfate (an adrenal hormone the body converts toward androgens); identifies hormone-driven loss needing different treatment; morning draw preferred |
| Zinc (serum) | 90–110 µg/dL | Deficiency impairs follicle keratin production | Conventional low cutoff ~60 µg/dL; draw fasting and separate from zinc supplements |

Qualitative markers help define success beyond photographs:

* Reduced daily hair shedding (fewer hairs on pillow, in shower, or on brush)
* Visibly increased density or coverage in previously thinning areas
* Improved hair-shaft thickness or texture
* Absence of scalp irritation, indicating good tolerability
* Subjective confidence in appearance, the practical endpoint for cosmetic use

## Emerging Research

Research framed for risk-aware adults centers on closing the gap between strong laboratory signals and unproven human regrowth, and on solving the delivery problem for a delicate protein.

* **Ongoing growth-factor scalp-serum trial:** A trial still in progress evaluates a premium scalp revitalizing elixir whose active arms include a growth-factor combination (IGF-1 and a related fibroblast growth factor) for scalp and hair-loss outcomes, reflecting continued industry interest in growth-factor and bioactive scalp formulations. [NCT07271212](https://clinicaltrials.gov/study/NCT07271212) (Hungkuang University; 60 participants; randomized, placebo-controlled; phase Not Applicable (a non-drug cosmetic study); hair density, hair loss, and scalp endpoints; estimated completion mid-2026).

* **Completed scalp-serum efficacy trial:** A finished randomized, placebo-controlled study evaluated a premium scalp revitalizing essence — including a growth-factor (IGF-1 plus a related fibroblast growth factor) arm — for sebum, hair density, and hair-loss outcomes, reflecting the same line of industry research. [NCT06985121](https://clinicaltrials.gov/study/NCT06985121) (Hungkuang University; 60 participants; completed 2025).

* **Completed growth-factor hair-serum trial (related molecule):** An early-phase study tested a keratinocyte growth factor (a closely related fibroblast growth factor) hair serum to prevent chemotherapy-induced hair loss in breast-cancer patients. [NCT04554732](https://clinicaltrials.gov/study/NCT04554732) (University of Arizona; 28 participants; Early Phase 1) — reported results did not show prevention of chemotherapy-induced alopecia, a relevant human data point on the broader difficulty of delivering growth-factor proteins to the scalp.

* **Delivery-system and engineered-protein research:** A major future direction noted in current reviews of growth-factor hair therapy is engineering fibroblast growth factors for greater stability and developing advanced carriers (such as exosome- and nanoparticle-based delivery) and gene- or mRNA-based approaches to overcome poor skin penetration. [Fibroblast Growth Factor-7 and Hair Biology: Bridging Basic Science and Therapeutic Applications](https://pubmed.ncbi.nlm.nih.gov/41614932/) - Huang et al., 2026, a review of fibroblast growth factor 7 (a closely related follicle growth factor) in hair biology, outlines these directions and could strengthen the case if delivery is solved.

* **Synergy with other growth factors:** Emerging mechanistic work on the cooperation of fibroblast growth factors with IGF-1 and VEGF suggests combination formulations may outperform single agents, a direction that could either strengthen the case (if combinations show clinical benefit) or weaken the standalone rationale for this protein. [Fibroblast Growth Factor-7 and Hair Biology: Bridging Basic Science and Therapeutic Applications](https://pubmed.ncbi.nlm.nih.gov/41614932/) - Huang et al., 2026 summarizes the synergy evidence for fibroblast growth factor 7, a closely related follicle growth factor.

* **Standalone human efficacy gap:** The most decisive future evidence would be a placebo-controlled human trial of topical Sh-Polypeptide-1 for androgenetic or diffuse hair loss with objective density endpoints; no such trial currently isolates this protein, and a null result would substantially weaken the case while a positive one would be the first true human support.

## Conclusion

Sh-Polypeptide-1 is a laboratory copy of basic fibroblast growth factor, a natural signal that tells skin and connective-tissue cells to multiply and builds the blood supply that helps move resting hairs into their growing phase. The biology is well established: in laboratory and animal work it reliably stimulates cell growth and hair-cycle activity, and a purified version is used in some countries as a medicine to heal skin wounds, which gives it a known track record acting on living skin.

Where the picture differs is on the human scalp. The biology is strong, but the human evidence that it regrows hair is essentially absent. A central obstacle is that this is a delicate protein that does not pass easily through intact skin, so much of its promise hinges on delivery methods that remain unsettled. It also does not act on the hormone pathway behind most pattern hair loss, limiting its value used alone.

In terms of how well it is tolerated, topical use appears low-risk, with mild scalp irritation the main concern, though dedicated safety testing is thin. The evidence base is also shaped by a conflict of interest, since most of the hair-specific findings come from the cosmetic suppliers and manufacturers who sell these products, which calls for extra caution in reading favorable claims. Overall, the evidence base is mechanistically rich but clinically immature, and how well it works in people remains genuinely uncertain.

**[Top](#top) - [Benefits](#expected-benefits) - [Risks](#potential-risks--side-effects) - [Protocol](#therapeutic-protocol)**