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sh-Polypeptide-11 for Hair Regrowth

Evidence Review created on 09/26/2026 using AI4L / Opus 5.5

Also known as: CG-aFGF, rh-Polypeptide-11, rh-Oligopeptide-13, Acidic Fibroblast Growth Factor, aFGF, Fibroblast Growth Factor 1, FGF1, FGF-1, Recombinant Human Acidic Fibroblast Growth Factor, rh-aFGF, rh-FGF1, Endothelial Cell Growth Factor, ECGF, Heparin-Binding Growth Factor 1, HBGF-1

Motivation

sh-Polypeptide-11 (recombinant acidic fibroblast growth factor) is a lab-made copy of a natural human signaling protein that tells skin cells to multiply and new small blood vessels to form. It appears in scalp serums, clinic scalp treatments and injectable hair products sold to people with thinning hair, including health-focused adults for whom age-related thinning is part of aging well, who hope it can wake resting hair roots and thicken existing hair.

The protein has a longer history in wound care, where lab-made versions have been tested on burns and slow-healing wounds. Interest in hair grew alongside the popularity of blood-derived scalp injections, which rest on a similar idea: delivering growth signals directly to the scalp. Animal studies suggest the protein can push resting hair roots into a growth phase, while other animal work points the other way.

This review examines what human, animal and laboratory evidence shows about sh-Polypeptide-11 for hair regrowth, how far that evidence reaches for a single ingredient usually sold inside multi-ingredient products, which risks accompany applying it to the skin or injecting it, and how its use is monitored.

Benefits - Risks - Protocol - Conclusion

This section lists expert and academic content that discusses sh-Polypeptide-11, the natural protein it copies, or growth-factor hair therapy in depth.

Only four items are listed because other academic work on FGF1 and hair consists of narrow single experiments (cited in the Mechanism, Benefits and Emerging Research sections) rather than overviews, and further PRP reviews largely duplicate the scope of the PRP review above; a 2015 mouse study of topical acidic FGF is not listed because it comes from the same research group as the review above. Peter Attia’s hair-loss AMA #63 is available only to paying members, so his free guest episode is listed instead. Andrew Huberman’s hair episode touches on PRP and microneedling only briefly, as ways to increase scalp blood flow, so it is not listed. Rhonda Patrick’s FoundMyFitness hair-loss content covers hormonal blockers, minoxidil, ketoconazole and microneedling, mentioning growth factors only in passing, so it is not listed. No directly relevant content was found from Chris Kresser, Life Extension Magazine or Lifespan.io: their hair-related material addresses nutrition, hormones, botanicals or other drug candidates, not FGF1 or growth-factor scalp therapy.

Grokipedia

  • Fibroblast growth factor 1

    Encyclopedia entry on FGF1, the natural protein sh-Polypeptide-11 copies, covering its structure, receptor signaling, roles in cancer and blood vessels, and recombinant wound-healing use in China; it does not address hair growth.

Examine

No Examine article on sh-Polypeptide-11 or acidic fibroblast growth factor exists. Examine covers dietary supplements, and topical cosmetic growth-factor ingredients fall outside that scope.

ConsumerLab

No ConsumerLab article on sh-Polypeptide-11 or acidic fibroblast growth factor exists. ConsumerLab tests dietary supplements, and topical cosmetic growth-factor ingredients have not been reviewed.

Systematic Reviews

No systematic review or meta-analysis has examined sh-Polypeptide-11 itself, so this section lists the closest reviews: one pooling growth-factor injections for androgenetic alopecia (pattern hair loss), one pooling trials that include recombinant acidic FGF, and reviews of the scalp injection and microneedling methods used to deliver growth-factor formulations.

Mechanism of Action

sh-Polypeptide-11 is a recombinant, 155-amino-acid copy of human FGF1 (acidic FGF), produced by fermentation in Escherichia coli.

  • Receptor binding: FGF1 is the only family member that activates all four fibroblast growth factor receptors (FGFRs, cell-surface switches for growth signals) and their variants, so its selectivity is low. Binding needs heparan sulfate (a sugar chain on cell surfaces) and triggers the MAPK/ERK (cell-division relay) and PI3K/AKT (cell-survival relay) pathways.
  • Follicle effects: In mice, topical FGF1 started anagen (the active growth phase) earlier and lengthened it, with earlier β-catenin (a follicle-growth switch) and Shh (sonic hedgehog, a growth signal) signaling. It also drives growth of dermal papilla cells (the follicle-base signaling hub) and small blood vessels.
  • Competing evidence: In newborn mice, repeated FGF injections delayed hair cycles, and FGF5, which uses the same receptors, pushes follicles into catagen (regression). The direction of effect may depend on timing, dose and follicle stage.
  • Delivery: The roughly 17 kDa (kilodalton, a unit of molecular size) protein does not cross intact outer skin; one study, run by a cosmetics manufacturer, found penetration only when packaged in lipid nanospheres. Clinics therefore pair it with microneedling, lasers or injection.
  • Pharmacology: No human pharmacokinetic (absorption and clearance) data exist for topical use. Native FGF1 is heat-sensitive and quickly broken down by protein-cutting enzymes unless bound to heparin, giving a short tissue half-life. It acts locally and is cleared by protein breakdown, not by CYP (cytochrome P450, drug-processing liver enzymes) metabolism.

Historical Context & Evolution

FGF1 was purified from brain tissue in 1984 as a heparin-binding protein that made fibroblasts (collagen-making skin cells) and blood-vessel cells multiply, and its gene was cloned in 1986. Its original intended use was tissue repair: recombinant versions were developed as topical wound-healing drugs, and a multicenter randomized trial in China reported faster healing of burns and skin-graft donor sites in 2007. A plasmid (a small DNA ring) carrying the FGF1 gene was also tested to grow new blood vessels in leg-artery disease, but the TAMARIS phase 3 trial found no reduction in amputation or death.

Hair research ran in parallel. In 1992, acidic FGF injected at the site protected young rats from chemotherapy-induced hair loss, while in 1993 daily FGF injections in newborn mice delayed hair cycles; these opposite findings remain unresolved. Mouse work in 2015 showed topical FGF1 could start and prolong the growth phase.

The cosmetic industry adopted recombinant growth factors in the 2000s. A Korean biotechnology supplier produced recombinant FGF1 under the ingredient name sh-Polypeptide-11 (trade name CG-aFGF), and it entered facial serums and later scalp serums and in-office hair treatments, as PRP popularized delivering growth factors to the scalp. Opinion has shifted with the evidence rather than settled: supporters cite animal regrowth data and a 2026 human biopsy series, while critics note that no controlled human hair trial of the ingredient alone exists.

Expected Benefits

High 🟩 🟩 🟩

Faster Wound Healing ⭕️ Not Central to Hair Regrowth

Recombinant acidic FGF applied to wounds speeds resurfacing by stimulating fibroblasts, lining cells and new blood vessels. A multicenter placebo-controlled trial in deep burns and skin-graft donor sites reported higher healing rates and shorter healing times (Ma et al., 2007), and a randomized trial after sinus surgery found more complete repair of the nasal lining (Xu et al., 2023). Both used pharmaceutical recombinant acidic FGF, not cosmetic sh-Polypeptide-11. This bears on skin recovery after scalp microneedling or laser, not on hair regrowth.

Magnitude: After sinus surgery, complete healing of the nasal lining at 12 weeks occurred in 18 treated patients versus 12 controls among 42 completers; the skin burn and donor-site trial reports significantly higher healing rates and shorter healing times without figures in its abstract.

Medium 🟩 🟩

No benefit reaches Medium: no single controlled trial has measured hair counts, hair thickness or another hair outcome with an sh-Polypeptide-11–containing product.

Low 🟩

Hair Growth and Growth-Phase Induction ⚠️ Conflicted

In an uncontrolled series, 30 adults injected with a commercial multi-ingredient product containing sh-Polypeptide-11 showed photographic improvement and more biopsy β-catenin (Adel et al., 2026). Topical FGF1 prolonged anagen in mice (Lin et al., 2015), but newborn-mouse injections delayed hair cycles (du Cros, 1993). Net: data lean toward growth.

Magnitude: Photographic and dermoscopic (magnified skin-surface imaging) hair appearance improved six months after two intradermal (into the skin) sessions of the multi-ingredient product; the study reports this only qualitatively and gives no hair-count or thickness figure.

Wrinkle Reduction ⭕️ Not Central to Hair Regrowth

In 25 women aged 51–59, four weeks of creams with a heat-stabilized recombinant FGF1 in lipid spheres reduced wrinkle depth and volume, without a control group (Żerańska et al., 2016). The cosmetics manufacturer ran the study. This bears on facial skin aging, not hair.

Magnitude: Wrinkle volume between the eyebrows fell from 6.44 to 5.48 mm³, and forehead dermis (inner skin layer) thickness rose about 10% after four weeks.

Speculative 🟨

Protection Against Chemotherapy- and Radiation-Induced Hair Loss

Acidic FGF protected rats from cytarabine chemotherapy hair loss (Jimenez & Yunis, 1992) and reduced radiation-induced follicle cell death in mice (Nakayama et al., 2009). No human data exist.

Benefit-Modifying Factors

  • Genetic polymorphisms: No gene variant is known to change response to FGF1. Androgen receptor (AR, the hormone docking site on follicles) gene variants drive pattern-loss severity and likely cap what any growth-factor add-on can achieve.
  • Baseline biomarkers: Low ferritin (iron stores), thyroid dysfunction or vitamin D deficiency cause shedding that growth factors cannot overcome; correcting them first gives a fair test. Thicker baseline shafts suggest earlier-stage loss with more responsive follicles.
  • Sex: No sex-specific data exist; the injection series enrolled 18 men and 12 women without separate analysis. Men rely on hormonal blockers for the main effect, while women with diffuse thinning use growth-factor topicals mainly as add-ons.
  • Pre-existing conditions: Early pattern thinning and telogen effluvium (stress- or illness-triggered shedding) retain follicles that can respond; advanced baldness and scarring alopecia (permanent follicle destruction) do not. Active scalp inflammation may blunt response until treated.
  • Age: Adults over 60 have fewer active follicles, slower hair cycles and slower healing, so gains from any topical growth factor are expected to be smaller; published human data cover adults only up to 59.

Potential Risks & Side Effects

High 🟥 🟥 🟥

No risk reaches High: no two controlled trials of sh-Polypeptide-11 or recombinant FGF1 applied to the scalp have recorded adverse events.

Medium 🟥 🟥

No risk reaches Medium: adverse-event data for this ingredient come only from an uncontrolled case series, reviews of other scalp injectables, and trials of FGF1 gene therapy.

Low 🟥

Transient Injection or Microneedling Reactions

Redness, mild swelling and pinpoint bleeding follow the scalp injection or microneedling used to deliver the protein. In 30 injected adults, only minor transient redness or swelling occurred (Adel et al., 2026); a review found no serious events in microneedling studies (English et al., 2022).

Magnitude: Redness and swelling are transient and resolve without treatment; the literature reports no incidence figure for these reactions, only no serious adverse events among 657 microneedling subjects and minor, self-resolving reactions in the 30-person injection series.

Complications of Scalp Mesotherapy

Repeated injection of multi-ingredient cocktails into the scalp has produced paradoxical hair loss, scarring and acute dermatitis in case reports and series (Beer et al., 2026). Contaminated injection equipment has caused outbreaks of severe bacterial skin infection after mesotherapy (Carbonne et al., 2009). None of these reports involved sh-Polypeptide-11 specifically.

Magnitude: Reported as isolated cases and outbreaks after repeated intradermal injection of multi-ingredient cocktails; the literature reports no incidence figure.

Tumor Promotion ⚠️ Conflicted

FGF1 drives cell division and blood-vessel growth, so feeding existing skin cancers is plausible. An FGF1 gene-therapy registry recorded two cancers among treated patients and none on placebo (Niebuhr et al., 2012); the larger TAMARIS trial found no safety issues (Belch et al., 2011). Net: no consistent cancer signal.

Magnitude: Cancer occurred in 2 of 47 FGF1-treated versus 0 of 25 placebo patients with severe leg-artery disease over three years; TAMARIS (525 patients) recorded no significant safety issues.

Speculative 🟨

Anti-Drug Antibodies and Lymph-Node Reactions

In wounded rabbits, 28 days of topical recombinant acidic FGF raised antibodies that did not block its activity and enlarged nearby lymph nodes, both fading after stopping (Zhang et al., 2020). No human data exist.

Hair-Cycle Delay or Altered Hair Fiber

Daily FGF injections delayed hair cycles in newborn mice (du Cros, 1993), and FGF1 shifted keratin protein make-up in cultured wool follicles (Bond et al., 1998). Basis is animal and culture data.

Allergic Contact Dermatitis

Recombinant proteins, preservatives and fragrances in serums can cause allergic contact dermatitis (an itchy allergic rash). No case involving sh-Polypeptide-11 has been published; the concern is mechanistic.

Risk-Modifying Factors

  • Genetic polymorphisms: No variants affecting FGF1 safety are known. Inherited cancer syndromes or familial melanoma raise the theoretical concern about repeated growth-factor exposure.
  • Baseline biomarkers: Low platelets or abnormal clotting tests raise bleeding risk with injection or needling; poorly controlled blood sugar raises infection risk at puncture sites.
  • Sex: No sex differences in adverse events are reported. Pregnancy and breastfeeding lack any safety data, a consideration specific to women.
  • Pre-existing conditions: Prior skin cancer, keloids (raised overgrown scars), scalp eczema or psoriasis, and immunosuppression raise tumor concern, scarring, irritation and infection risk respectively.
  • Age: Older adults have thinner skin, slower healing and more frequent anticoagulant (blood-thinning medication) use, increasing bruising and infection risk after scalp procedures.

Key Interactions & Contraindications

Prescription medications

  • Topical minoxidil — monitor (additive): Commonly combined; no chemical interaction is known, and growth-phase effects may add. Stacked solvents can increase scalp irritation; applying products at separate times of day limits it.
  • 5-alpha-reductase inhibitors (medications that block testosterone’s conversion to the more potent dihydrotestosterone: finasteride, dutasteride) — no known interaction: They act on the hormonal driver sh-Polypeptide-11 does not touch; combined use is complementary and needs no adjustment.
  • Anticoagulants and antiplatelets (blood thinners: warfarin, apixaban, clopidogrel) — caution with injection or microneedling: Increased bruising and bleeding at puncture sites. Clinics review these beforehand; any interruption is decided only by the prescribing physician.
  • Retinoids (vitamin A–derived medications: topical tretinoin, oral isotretinoin) — caution: Topical retinoids add scalp irritation; oral isotretinoin impairs healing, and clinics commonly defer microneedling or laser for several months after it.
  • FGFR inhibitors (cancer drugs that block the receptors sh-Polypeptide-11 activates: erdafitinib, pemigatinib, futibatinib) — caution (theoretical antagonism): Likely cancel any effect and cause hair and nail changes themselves; use is coordinated with the oncologist.
  • Immunosuppressants (immune-dampening medications: methotrexate, systemic corticosteroids, JAK inhibitors such as baricitinib, which block Janus kinase immune-signaling enzymes) — caution with injection: Higher infection risk and slower healing at puncture sites; sterile technique and a check 1–2 weeks after each session mitigate this.

Over-the-counter medications

  • Aspirin and NSAIDs (nonsteroidal anti-inflammatory drugs: ibuprofen, naproxen) — caution with procedures: More bruising after injection or microneedling; clinics often ask for a pause of several days beforehand when medically permissible.
  • Ketoconazole shampoo — no known interaction: Often combined for its anti-dandruff and mild anti-androgen effect; separating washing and serum application by several hours keeps the leave-on serum on the scalp.

Supplements

  • Fish oil, vitamin E, ginkgo, high-dose garlic — caution with procedures: Mildly increase bleeding and bruising at puncture sites; pausing them several days before injection sessions is common clinic practice.
  • High-dose biotin — monitor laboratory tests: No interaction with the protein, but biotin distorts thyroid and other lab results used in monitoring; stopping it 2–3 days before blood draws avoids false readings.
  • Copper peptide (GHK-Cu, a copper-binding tripeptide), topical caffeine and other hair peptides — monitor (additive): Often co-formulated; effects on follicle signaling may add, with more irritation and cost. No combination has been tested against sh-Polypeptide-11 alone.
  • Iron, zinc and vitamin D — monitor (additive only when deficient): Correcting deficiencies removes a barrier to response; no benefit beyond repletion is shown, and excess iron is harmful.

Other interventions

  • Microneedling, fractional laser, low-level light therapy and PRP — caution (potentiating): Needling and laser open channels that let the protein reach follicles, and PRP adds overlapping growth factors. Combined procedures raise irritation and infection risk, mitigated by sterile technique and spacing sessions.

Populations who should avoid Sh-Polypeptide-11:

  • Active skin cancer or precancerous lesions on the scalp, or melanoma treated within the past 5 years
  • Pregnancy or breastfeeding (no safety data)
  • Scarring alopecia such as lichen planopilaris (inflammatory scarring hair loss), or active scalp infection or dermatitis at the treatment site
  • Known allergy to any product component
  • For injection or microneedling: keloid-prone skin, platelet count below 50,000/µL, or uncontrolled diabetes (HbA1c, a three-month blood-sugar average, above 9%)
  • Children and adolescents under 18 years

Risk Mitigation Strategies

  • Patch test before scalp use: Applying a small amount behind the ear for 48 hours screens for allergic contact dermatitis before whole-scalp use.
  • Sterile injectables only: Limiting intradermal use to products manufactured and labeled sterile for injection, given by trained clinicians with sterile technique, reduces the infection, scarring and paradoxical hair loss reported after mesotherapy.
  • Baseline scalp skin check: A dermatologist examination of pigmented or changing scalp lesions before starting addresses the theoretical risk of growth factors feeding existing skin cancers.
  • Conservative needling depth: Microneedling depths of 0.5–1.5 mm at intervals of 2–4 weeks limit bleeding, redness and scarring while still opening delivery channels.
  • Bleeding-risk review: Reviewing anticoagulants, NSAIDs and bleeding-prone supplements before procedures reduces bruising and bleeding at puncture sites.
  • Six-month response check: Photographs and trichoscopy (magnified scalp imaging) at six months identify non-responders, limiting prolonged exposure, cost and cumulative antibody formation without benefit.
  • Post-procedure care: Keeping the treated scalp clean and avoiding swimming pools and heavy sweating for 24 hours after needling or injection reduces infection risk.

Therapeutic Protocol

  • No standardized regimen: No trial has defined an effective sh-Polypeptide-11 dose for hair. Products rarely disclose concentration, and cosmetic serums typically contain parts-per-million amounts alongside other growth-factor copies and peptides.
  • Home topical approach: Leave-on scalp serums are applied once or twice daily to thinning areas per manufacturer labels, often alongside minoxidil; without a penetration carrier, little intact protein is expected to reach follicles.
  • In-office microneedling or laser approach: Clinics apply growth-factor solutions such as KeraFactor, marketed to physicians, right after microneedling or fractional laser, typically as a series of about six sessions, weekly to monthly, then periodic maintenance.
  • Injectable approach: The only published protocol with an sh-Polypeptide-11–containing product injected 5 mL intradermally on a 1 cm grid, two sessions two weeks apart (Adel et al., 2026).
  • Laser-assisted approach: A Korean dermatology group applied a growth-factor solution of unspecified composition after each of 12 weekly thulium laser sessions, adding density and thickness gains over laser alone on the split scalp (Cho et al., 2018).
  • Time of day: No circadian data exist; leave-on serums are commonly applied in the evening so the product stays on the scalp for hours without washing or sweating.
  • Half-life: No human pharmacokinetic data exist; native FGF1 is unstable at body temperature without heparin and rapidly broken down, so any effect depends on repeated local exposure, not accumulation.
  • Single versus split dosing: Home serums are used once or twice daily; in-office treatments are single sessions. No study has compared split with single application.
  • Genetic factors: No polymorphism is known to alter response to FGF1; androgen receptor gene variants and polygenic risk set pattern-loss severity and likely the ceiling for any growth-factor add-on.
  • Sex differences: No sex-specific dosing exists; the injection series did not analyze men and women separately. Women with pattern thinning commonly combine topicals with minoxidil or anti-androgen therapy.
  • Age: Older adults have fewer active follicles and slower hair cycles; no age-specific protocol exists, and thinner, slower-healing skin favors gentler needling depths.
  • Baseline biomarkers: Low ferritin, thyroid dysfunction or vitamin D deficiency cause or worsen shedding; correcting them is part of standard hair-loss workups before judging response to any topical.
  • Pre-existing conditions: Response is plausible only where follicles survive, as in pattern thinning or telogen effluvium, not scarring alopecia; autoimmune alopecia areata (patchy immune-driven hair loss) lacks data for this ingredient.

Discontinuation & Cycling

  • Duration: Use is open-ended for chronic pattern hair loss; any benefit is expected to fade after stopping, as with other non-hormonal hair treatments, though no study has followed users beyond six months.
  • Withdrawal effects: None reported. Unlike minoxidil, no rebound shedding has been described, though no study has looked for it.
  • Tapering: Not applicable; home serums can be stopped at once. In-office series usually move from a loading phase to less frequent maintenance sessions.
  • Cycling: No evidence supports cycling to maintain efficacy; receptor desensitization during continuous FGF exposure has not been studied in follicles.

Sourcing and Quality

  • Identity and labeling: Labels list the ingredient under its INCI (International Nomenclature of Cosmetic Ingredients) name sh-Polypeptide-11, or older names rh-Polypeptide-11 and rh-Oligopeptide-13. Concentration is rarely stated, and “growth factor” claims without an INCI listing cannot be verified.
  • Supplier and form: The ingredient is mainly produced by the Korean biotechnology company Caregen as CG-aFGF through Escherichia coli fermentation; finished-product brands buy and dilute it, often within multi-peptide complexes.
  • Stability: Recombinant FGF1 loses activity with heat, repeated freeze–thaw cycles and protein-cutting enzymes; airless or single-dose ampoule packaging, refrigeration and lipid-carrier formulations help preserve bioactivity.
  • Third-party testing: No independent laboratory testing of sh-Polypeptide-11 content or activity in finished products has been published; bioactivity claims rest on supplier and manufacturer data.
  • Cosmetic versus injectable grade: Cosmetic serums are not certified sterile for injection; intradermal use relies on products manufactured as sterile injectables, such as the two-part kit in the published injection series.
  • Brands: Products listing it include KeraFactor (a clinic-oriented scalp solution), Bio-Placenta peptide complexes and Korean growth-factor ampoules; none has published a controlled hair trial of its finished product.

Practical Considerations

  • Time to effect: Because hair cycles are slow, visible change takes at least 3–6 months; the only injection series assessed outcomes at six months.
  • Common pitfalls: Using it instead of proven therapies such as minoxidil or finasteride, skipping diagnosis of the hair-loss type, injecting non-sterile cosmetics, judging results before six months, and relying on marketing photographs.
  • Regulatory status: In the US and EU, sh-Polypeptide-11 is a cosmetic ingredient, not an approved hair-loss drug, and hair-growth claims are unapproved drug claims. Recombinant acidic FGF is approved in China as a topical wound-healing drug.
  • Cost and accessibility: Home serums commonly cost US$50–200 per month, and in-office series cost several hundred dollars per session. Insurers cover no cosmetic hair treatments, so no payer incentive favors this or cheaper generic alternatives.

Interaction with Foundational Habits

  • Sleep: None direct; the protein acts locally and does not reach the brain. Evening application suits leave-on serums. Poor sleep and circadian disruption are linked to shedding, which can mask any topical effect.
  • Nutrition: Indirect; follicles need adequate protein, iron, zinc and vitamin D to respond to growth signals. Severe caloric restriction and rapid weight loss trigger telogen (resting-phase) shedding. No foods are known to alter sh-Polypeptide-11 activity.
  • Exercise: None direct. Heavy sweating shortly after applying a leave-on serum may dilute it, so application after the post-workout shower is common practice. Exercise-related scalp blood flow has not been shown to enhance its effect.
  • Stress management: Indirect; chronic stress raises cortisol and can push follicles into telogen shedding, blunting visible results. sh-Polypeptide-11 has no known effect on cortisol or the stress response.

Monitoring Protocol & Defining Success

Baseline testing before starting identifies the type of hair loss and correctable causes. It includes standardized scalp photographs from fixed angles, trichoscopy (magnified scalp imaging) counting hairs and measuring shaft thickness over a marked area, and blood tests for ferritin, thyroid function and vitamin D. Women with pattern thinning or irregular cycles often add androgen testing, and any pigmented or changing scalp lesion is assessed before growth-factor use.

Ongoing monitoring repeats photographs and trichoscopy at 3, 6 and 12 months, then every 6–12 months. Blood tests are repeated at 6–12 months only if baseline values were abnormal or shedding worsens, and injection sites are checked 1–2 weeks after each session for infection or nodules.

Biomarker Optimal Functional Range Why Measure It? Context/Notes
Hair density (trichoscopy) No established target; track increase from own baseline Primary response measure Same marked site, lighting and magnification each visit; a small scalp tattoo dot aids relocation
Hair shaft diameter No established target; track increase from own baseline Detects thickening before density changes Measured on the same marked area; reflects reversal of miniaturization (follicle shrinkage)
Ferritin 50–100 ng/mL Iron stores support follicle growth Conventional range about 15–150 ng/mL (women); inflammation falsely raises it; pair with CBC (complete blood count); fasting not required
TSH 0.5–2.5 mIU/L Thyroid disorders cause shedding TSH (thyroid-stimulating hormone); conventional range about 0.4–4.5 mIU/L; pair with free T4 (thyroxine); morning draw; pause biotin 2–3 days before
25-hydroxyvitamin D 40–60 ng/mL Deficiency is linked to hair loss Conventional sufficiency cutoff 30 ng/mL; any time of day
Free testosterone and DHEA-S (women) Lower half of the laboratory reference range Androgen excess drives female pattern loss DHEA-S (dehydroepiandrosterone sulfate, an adrenal androgen); conventional ranges are age-specific; morning draw in the early menstrual cycle
Standardized photographs Visibly greater scalp coverage than baseline Global response assessment Same camera, distance, lighting and hair styling; wet or parted hair shows coverage best

Qualitative markers

  • Daily shedding seen in the shower, on pillows or on brushes
  • Visible scalp coverage at the part line and crown
  • Hair texture, thickness and styling volume
  • Scalp comfort: itching, redness or irritation after application or procedures
  • Personal satisfaction with appearance

Emerging Research

  • Peptide serum versus minoxidil trial: A triple-blind randomized trial compares a peptide growth-factor hair serum with 2% minoxidil in 80 adults with pattern hair loss over 24 weeks, measuring hair density (NCT07536100); the registry does not state whether sh-Polypeptide-11 is an ingredient.
  • Thulium laser plus growth-factor serum: A 30-person randomized study in Hamburg compares laser alone with laser plus growth-factor serum, with or without LED (light-emitting diode) light, measuring density and thickness (NCT07079657).
  • FGF-family serum for chemotherapy hair loss: A completed early-phase trial of a keratinocyte growth factor (FGF7) hair serum (NCT04554732) reported that none of 20 evaluable women achieved meaningful hair preservation (Mann et al., 2026), a human counterpoint to rodent acidic-FGF protection studies.
  • Gene-delivery microneedle patch: A mouse study delivered an acidic FGF gene through a microneedle patch, outperforming recombinant protein for follicle regeneration (Zhou et al., 2026), suggesting protein instability limits current products.
  • Evidence that could weaken the case: No trial isolates sh-Polypeptide-11 from multi-ingredient products; the only human series lacks controls (Adel et al., 2026), and FGF-delayed hair cycles in newborn mice (du Cros, 1993) remain unexplained.
  • Long-term growth-factor safety: The Cochrane review found growth-factor safety poorly reported (Martí-Carvajal et al., 2015); no long-term cancer surveillance exists for repeated topical FGF1 on the scalp.

Conclusion

sh-Polypeptide-11 is a lab-made copy of a natural human growth protein that makes skin cells divide and new small blood vessels form. For health-focused adults already using proven hair-loss treatments, it is sold as an add-on in scalp serums, clinic treatments and injection kits.

The case for hair regrowth rests mainly on animal studies, where the protein pushed resting hair roots into growth, and on one small human injection study without a comparison group, using a product that contained it among many other ingredients. Other animal work found that related proteins delayed hair cycles, so even the laboratory picture is mixed. The strongest human evidence concerns faster wound healing, which bears on skin recovery after scalp needling rather than on hair itself. No controlled human study has tested the ingredient alone for hair.

The known risks come mostly from how it is delivered: short-lived redness and swelling after needling or injection, and rare but serious reactions when cosmetic mixtures are injected. Concern about feeding existing skin cancers remains unproven, with inconsistent signals from studies of the protein given to grow blood vessels.

One of the skin studies was run by a cosmetics maker, and the injection study used a commercially supplied product. Overall, sh-Polypeptide-11 is a biologically plausible but largely untested hair ingredient, with a low but poorly described risk profile when applied to intact skin.

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