evipedia.ai
← Back

sh-Polypeptide-86 for Hair Regrowth

Evidence Review created on 09/28/2026 using AI4L / Opus 5.5

Also known as: Follistatin, Recombinant Human Follistatin, FST, Nicotiana benthamiana Hexapeptide-40 sh-Polypeptide-86

Motivation

sh-Polypeptide-86 is a cosmetic ingredient built to match human follistatin, a protein the body uses to switch off signals that keep hair follicles in their resting state. It is made by bacterial fermentation, with a related, slightly modified version grown in a tobacco-related plant, and it now appears in scalp serums, shampoos and lash products sold for thinning hair. It draws interest as a drug-free way to act on the hair growth cycle itself rather than on hormones.

Interest grew from animal studies of follistatin’s role in deciding when hair follicles grow and when they rest, and from an injected scalp treatment that combined follistatin with other growth signals. The ingredient reached a wider audience after it was featured in a longevity-branded hair serum.

This review examines sh-Polypeptide-86 applied to the scalp for hair regrowth: how it is proposed to work, what the human evidence actually covers, which risks and unknowns exist, and how it sits beside established hair-loss options for health-focused adults.

Benefits - Risks - Protocol - Conclusion

The following items discuss sh-Polypeptide-86 by name, the follistatin biology it is designed to replicate, or the hair growth cycle it targets.

No directly relevant content was found from Rhonda Patrick, Chris Kresser, Life Extension Magazine or Lifespan.io: site searches returned no hair-focused follistatin content, and their follistatin mentions concern muscle, exercise or systemic gene therapy. Peter Attia’s hair-loss episode does not discuss follistatin or this ingredient, and its full content is members-only.

Grokipedia

  • Follistatin

    No entry exists for sh-Polypeptide-86; this page covers follistatin, the human protein it replicates, including its activin-blocking biology, but does not discuss hair growth or cosmetic use.

Examine

  • Follistatin

    Examine has no sh-Polypeptide-86 page; this outcome page summarizes follistatin’s muscle and reproductive roles and cites the follistatin-containing scalp injection trial, not topical use.

ConsumerLab

No ConsumerLab article on sh-Polypeptide-86 or follistatin was found.

Systematic Reviews

No systematic reviews or meta-analyses for sh-Polypeptide-86 were found on PubMed as of September 28, 2026.

The claimed hair-regrowth effect is not represented by any systematic review or meta-analysis. The principal risk, forgoing proven treatments, is represented by a meta-analysis of those treatments:

Mechanism of Action

Follistatin is a secreted glycoprotein (a protein carrying sugar chains) that captures and neutralizes members of the TGF-β (transforming growth factor beta, a family of growth-regulating signal proteins) superfamily, chiefly activin A, myostatin (a muscle-growth brake) and several BMPs (bone morphogenetic proteins, signals that help hold hair follicles at rest).

  • Hair cycle target: BMP signaling from surrounding skin keeps follicle stem cells quiet during telogen (resting phase). Blocking it favors entry into anagen (growth phase). Follistatin rises in late telogen, spreads growth waves across mouse skin and declines with age (Chen et al., 2014).
  • Development: Follistatin-deficient mice show delayed follicle formation (Nakamura et al., 2003).
  • The ingredient: sh-Polypeptide-86 is the INCI (International Nomenclature of Cosmetic Ingredients, the standardized label name) for recombinant human follistatin produced by bacterial fermentation; a separate fusion form with hexapeptide-40, made in the plant Nicotiana benthamiana, contains 294 amino acids (INCIDecoder).
  • Competing view: At roughly 32 kDa (kilodaltons, a unit of molecular size), the protein far exceeds the 500-dalton limit cited for passage through intact skin (Bos & Meinardi, 2000). Delivery to the follicle and activity after formulation are unproven. More is not necessarily better: widespread follistatin overexpression produced irregular fur in mice (Guo et al., 1998).
  • Pharmacology: Its absorption, clearance and skin half-life in humans are unknown. Binding is highest for activin, lower for myostatin and BMPs. A heparin-binding region (attaching to sugar chains on cell surfaces) keeps it local. It is degraded by protein-cutting enzymes, with no cytochrome P450 (liver drug-processing enzymes) involvement.

Historical Context & Evolution

Follistatin was first isolated in 1987 from ovarian follicular fluid as a suppressor of FSH (follicle-stimulating hormone, a pituitary fertility hormone), which gave the protein its name. Its original context was reproductive endocrinology, not hair.

The hair connection emerged from genetics. Mice lacking follistatin died at birth with shiny, taut skin and abnormal whiskers (Matzuk et al., 1995), and later work showed that the balance of follistatin and activin governs body-hair follicle development and cycling (Nakamura et al., 2003).

The first human test was run by Histogen, the manufacturer, which holds a direct financial interest in the outcome. A single injection of its cell-derived Hair Stimulating Complex, containing follistatin plus other growth factors, improved hair measures over placebo in 26 men (Zimber et al., 2011). A larger sponsor trial of the same product in 2020–2021 showed within-group hair gains but did not separate statistically from placebo (Histogen, 2021); no further trial has been reported since.

In parallel, cosmetic suppliers registered bacterially produced follistatin as sh-Polypeptide-86, plus a plant-made fusion form, and both entered scalp serums, shampoos and lash products. Visibility rose sharply in 2025 when a longevity brand featured it in a peptide serum. A 2022 mouse gene-therapy paper claiming follistatin prevented age-related hair loss was later retracted (Jaijyan et al., 2022), which removed one piece of supporting evidence without new evidence against the hair mechanism emerging. The question now is whether a topical form reaches the follicle at all.

Expected Benefits

High 🟩 🟩 🟩

No benefit reaches High: the only human hair outcome data come from injected multi-factor mixtures, not from sh-Polypeptide-86 applied to the scalp.

Medium 🟩 🟩

No benefit reaches Medium: no controlled trial has measured a human hair outcome for sh-Polypeptide-86 or for follistatin given alone.

Low 🟩

Increased Hair Density and Shaft Thickness ⚠️ Conflicted

Human evidence is indirect: a sponsor-run placebo-controlled trial of one scalp injection of a follistatin-containing growth-factor mixture improved hair measures in 26 men (Zimber et al., 2011). A larger follow-up with different endpoints and three injection rounds did not beat placebo (Histogen, 2021). Net, topical benefit remains unproven.

Magnitude: Terminal (thick, pigmented) hair density rose 20.6% versus 4.4% with placebo 12 weeks after one injection of the mixture; no figure exists for topical sh-Polypeptide-86.

Speculative 🟨

Earlier Entry Into the Hair Growth Phase

Follistatin promotes follicle development and triggers spreading growth waves in mice, and its levels fall with age (Chen et al., 2014). The basis is animal work only.

Formation of New Hair Follicles

In mouse skin cells, follistatin was among the genes required for inducing new follicles (Bak et al., 2015). No human data exist; the basis is mechanistic only.

Eyelash and Eyebrow Fullness

sh-Polypeptide-86 appears in several lash and brow serums. No controlled study has tested it on lashes or brows; the basis is extrapolation from scalp mechanism only.

Scalp Skin Conditioning ⭕️ Not Central to Hair Regrowth

Its registered cosmetic function is skin conditioning (COSMILE Europe). This bears on scalp comfort and appearance, not regrowth; no controlled data exist, and the basis is mechanistic only.

Benefit-Modifying Factors

  • Genetic polymorphisms: Variants in the AR gene (androgen receptor, which senses testosterone-derived hormones) drive pattern hair loss. No study links AR or FST (the follistatin gene) variants to response, and follistatin does not address the androgen sensitivity that shrinks follicles.
  • Baseline biomarkers: Low ferritin (stored iron), thyroid dysfunction or low vitamin D can cause shedding independently of follicle signaling. Uncorrected deficits would blunt or mask any effect of a topical peptide.
  • Sex: Published follistatin-mixture data come from men only; a female trial posted no results (NCT03662854). Women’s thinning is more often diffuse and hormonally mixed, so any benefit may differ, but no data exist.
  • Pre-existing conditions: Pattern hair loss with miniaturized but living follicles is the proposed target. Scarring alopecias (destroyed follicles), alopecia areata (immune attack on follicles) and telogen effluvium (stress-triggered shedding) have different drivers and no rationale for benefit.
  • Age: Follistatin declines with age in mice, suggesting a rationale in older adults. Long-standing baldness leaves fewer recoverable follicles, however, likely limiting any effect; no age-stratified human data exist.

Potential Risks & Side Effects

High 🟥 🟥 🟥

No risk reaches High: no trial of sh-Polypeptide-86 has recorded adverse events, and follistatin safety data come only from injected mixtures and gene therapy.

Medium 🟥 🟥

No risk reaches Medium: no single controlled human study of topical follistatin has reported adverse-event rates.

Low 🟥

Local Scalp Irritation or Sensitization

Serums containing sh-Polypeptide-86 also contain preservatives, acids and penetration enhancers that can irritate or sensitize scalp skin. An injected follistatin-containing mixture caused no reported adverse reactions in 26 men over one year (Zimber et al., 2011). Topical data are absent.

Magnitude: 0 of 26 participants had adverse reactions to the injected mixture; no reaction rate has been published for topical products.

Delayed Use of Proven Hair-Loss Treatments

Pattern hair loss progresses over time, and minoxidil, finasteride and low-level laser therapy each outperformed placebo in meta-analyses of randomized trials (Adil & Godwin, 2017). Months spent on an unproven serum instead can mean losing hair that proven options might have preserved.

Magnitude: The forgone benefit equals the proven treatments’ placebo-adjusted gains in the meta-analysis: about 15 hairs/cm² with 5% minoxidil in men and about 12 hairs/cm² with 2% minoxidil in women.

Speculative 🟨

Slower Wound Healing After Microneedling

Mice overproducing skin follistatin healed wounds slowly, with weaker granulation tissue (new repair tissue) (Wankell et al., 2001). Relevance to serums applied after microneedling is unknown; the basis is animal data only.

Uncertain Skin-Cancer Effects

Follistatin is strongly expressed in basal cell carcinoma, the most common skin cancer (Kim et al., 2016), and growth-factor cosmetics lack long-term safety data. The basis is mechanistic only.

Reduced Skin Immune Sentinel Cells

Epidermal follistatin overexpression sharply reduced Langerhans cells (immune cells that patrol the skin) in mice (Stoitzner et al., 2005). The basis is animal data only.

Hormonal and Reproductive Effects

Follistatin suppresses FSH; widespread overexpression caused infertility and irregular fur in mice (Guo et al., 1998). Systemic exposure from scalp use is expected to be negligible; the basis is animal data.

Reactions to Production Residues

Recombinant proteins may carry host residues: bacterial endotoxin (cell-wall toxin) with Escherichia coli-made sh-Polypeptide-86, plant proteins or sugar chains with the plant-made fusion form. Immune reactions are theoretical; none have been reported.

Risk-Modifying Factors

  • Genetic polymorphisms: No drug-metabolism variant alters handling of this protein. Basal cell nevus syndrome (inherited PTCH1 gene defect that unleashes hedgehog growth signaling) raises concern given follistatin’s link to basal cell carcinoma.
  • Baseline biomarkers: No laboratory value predicts reactions. Baseline scalp state matters: active dermatitis, psoriasis or broken skin raise irritation risk and may increase penetration of the protein.
  • Sex: Pregnancy, attempts to conceive and breastfeeding carry unknown risk given follistatin’s reproductive role. No sex-specific adverse-event data exist.
  • Pre-existing conditions: Prior scalp skin cancer, actinic keratoses (sun-damage precancers), a history of contact allergy, or impaired wound healing (e.g., diabetes) raise theoretical concern.
  • Age: Older adults have thinner skin barriers and more sun-damaged scalps with precancerous lesions, raising irritation and theoretical tumor concerns; no age-specific safety data exist.

Key Interactions & Contraindications

  • Topical minoxidil (over-the-counter): Monitor. No chemical interaction is known, but layering adds irritation from minoxidil’s propylene glycol vehicle and may alter absorption. Applying at separate times (e.g., minoxidil morning, serum evening) reduces overlap.
  • 5-alpha-reductase inhibitors (drugs blocking conversion of testosterone to its more potent form: finasteride, dutasteride): No interaction expected; they act on androgens, follistatin on follicle signaling. Starting one product at a time preserves attribution of any change.
  • Topical retinoids (vitamin A-derived skin drugs) and exfoliating acids (tretinoin, salicylic acid, glycolic acid): Caution. Barrier disruption increases irritation and may raise protein penetration. Separating application times or reducing frequency limits irritation.
  • Microneedling, dermarollers and fractional lasers: Caution. These greatly increase delivery of large proteins into deeper skin, turning a cosmetic into a quasi-injection with unknown safety and theoretically slower healing. Waiting 24 hours after the procedure limits exposure.
  • Anticoagulants and antiplatelet drugs (blood thinners: warfarin, apixaban, clopidogrel, aspirin): Monitor, relevant only with microneedling: scalp bleeding and bruising increase. Shallower needle depth (0.5 mm or less) reduces bleeding.
  • Immunosuppressants (immune-dampening drugs: tacrolimus, cyclosporine, methotrexate): Caution. Theoretical additive reduction in skin immune surveillance, given follistatin’s effect on Langerhans cells in mice. Annual skin examinations address the added skin-cancer concern.
  • Injectable follistatin products (FS-344, a follistatin form sold as an unregulated research peptide; AAV-follistatin gene therapy, using adeno-associated virus, a harmless gene-carrying virus): Caution. Additive activin and myostatin blockade may affect reproductive hormones. Avoiding unregulated systemic products removes this interaction.
  • Other growth-factor products (platelet-rich plasma, exosome serums containing cell-released vesicles, sh-Oligopeptide-1 serums): Caution. Additive, uncharacterized growth-factor load on scalp skin with no stacking safety data. Introducing one product at a time allows reactions to be traced.
  • (−)-Epicatechin and cocoa flavanol supplements: Monitor, additive in principle. Epicatechin raised the circulating follistatin-to-myostatin ratio in a small human study (Gutierrez-Salmean et al., 2014); any added scalp effect is unknown and likely negligible.
  • Common hair supplements (biotin, iron, zinc, saw palmetto): No interactions known. Biotin above 5 mg daily can distort thyroid laboratory results; pausing it 2–3 days before blood tests avoids misreading.

Populations who should avoid Sh-Polypeptide-86:

  • Pregnant or breastfeeding people, and those actively trying to conceive (all trimesters; no safety data)
  • People with scalp skin cancer (basal or squamous cell carcinoma) treated within the past 5 years, or with basal cell nevus syndrome
  • People with open wounds, active infection, or uncontrolled psoriasis or seborrheic dermatitis (dandruff-type scalp inflammation) at the application site
  • People with known allergy to any product component
  • People with undiagnosed patchy, scarring or rapid-onset hair loss, until the cause is established

Risk Mitigation Strategies

  • Patch testing before scalp use: a small amount applied behind the ear once daily for 3–5 days; redness, itch or swelling signals irritation or allergic contact dermatitis before the whole scalp is exposed.
  • Maintaining proven therapy: using the serum alongside minoxidil, finasteride or low-level laser therapy rather than instead of them prevents the forgone benefit of delaying effective treatment.
  • Spacing from microneedling: waiting at least 24 hours after microneedling, or using sterile single-use products, limits uncontrolled dermal protein exposure and theoretical delayed wound healing.
  • Scalp skin examinations: dermatologist examination at baseline and every 12 months (every 6 months after prior skin cancer) addresses the uncertain skin-cancer effects of growth-factor products.
  • Avoidance around pregnancy: stopping at least 1 month before attempting conception and throughout pregnancy and breastfeeding removes the unknown reproductive-hormone risk.
  • Choosing documented products: products with disclosed concentrations and batch certificates of analysis reduce the risk of impurities and production-residue reactions.
  • Defined 6-month trial with photographs: standardized photographs at baseline, 3 and 6 months limit prolonged spending on a non-responding product and flag progression early.

Therapeutic Protocol

  • Standard cosmetic protocol: No clinically validated dose exists and concentrations are usually undisclosed. Brands direct about 1 mL applied to a dry scalp once or twice daily, massaged in and left on, as Blueprint instructs (morning or night).
  • Stand-alone serum approach: Promoted by longevity and wellness brands (Blueprint, Vegamour, Nécessaire), which position peptide serums alone for hair “vitality” and fullness, with claims limited to appearance.
  • Add-on approach: Evidence-review sites such as Perfect Hair Health (which sells competing hair topicals) frame peptide serums as, at most, additions to minoxidil, finasteride or low-level laser therapy, never replacements, given the absent human data.
  • Microneedling-assisted approach: Aesthetic clinics apply growth-factor serums right after microneedling (0.5–1.5 mm, every 2–4 weeks) to bypass the skin barrier. This has not been tested for sh-Polypeptide-86 specifically.
  • Injected follistatin mixtures (investigational): Histogen’s Hair Stimulating Complex used 20 injections of 0.1 mL into the scalp skin at weeks 0, 6 and 12 (NCT04435847). It is not commercially available.
  • Time of day: No evidence favors morning or evening. Evening application on a dry scalp gives longer contact before washing or sweating.
  • Half-life: No human data on absorption or clearance exist for topical sh-Polypeptide-86. As a protein it is expected to be broken down by skin enzymes, which favors daily rather than intermittent application.
  • Single vs split dosing: Brands allow once- or twice-daily use; no data show twice daily outperforms once. A single daily application is the common default and limits irritation.
  • Genetic polymorphisms: No variant guides dose. A strong family history of early balding signals high androgen sensitivity, which androgen-targeting therapy addresses and a follistatin serum does not.
  • Sex: Application is the same for both sexes. Women often pair it with minoxidil or spironolactone (an androgen-blocking medication), men with finasteride; use is excluded during pregnancy.
  • Age: Adults over 60 with long-standing thinning have fewer recoverable follicles, so retention is the realistic aim. Thinner, sun-damaged scalps may tolerate only once-daily or alternate-day use.
  • Baseline biomarkers: Correcting low ferritin, thyroid dysfunction or vitamin D deficiency before starting removes treatable shedding causes that would otherwise confound any response.
  • Pre-existing conditions: Seborrheic dermatitis or psoriasis is usually controlled first (e.g., ketoconazole shampoo), since inflamed scalps react more and absorb differently.

Discontinuation & Cycling

  • Duration: Use is open-ended and cosmetic. Any benefit would likely require ongoing application, as with other hair-growth topicals; a 6-month trial is the usual checkpoint for continuing.
  • Withdrawal effects: None are known. Any gained hair would be expected to regress over months after stopping, by analogy with minoxidil, though this is untested.
  • Tapering: Not required; abrupt stopping is acceptable. Within a combined regimen, changing one product at a time shows which component mattered.
  • Cycling: No evidence supports cycling. Follistatin acts by binding signal proteins, and no desensitization mechanism has been described.
  • Stopping triggers: Persistent irritation, a new or changing scalp lesion, pregnancy, or no measurable change on standardized photographs after 6 months.

Sourcing and Quality

  • Ingredient identity: “sh-Polypeptide-86” and “Nicotiana benthamiana Hexapeptide-40 sh-Polypeptide-86” are different INCI entries, the latter a 294-amino-acid fusion form. Labels naming the exact entry reveal which material is present.
  • Concentration disclosure: The ingredient usually appears near the end of ingredient lists, implying low concentration, and few brands disclose amounts. Disclosed concentrations allow comparison between products.
  • Third-party testing: Batch certificates of analysis confirming identity, microbial limits and heavy metals are the main quality signal; some brands, including Blueprint, publish them for their products.
  • Protein stability: Heat, light and preservative choice affect protein integrity. Opaque airless packaging, storage as labeled and use within the stated period after opening help preserve activity.
  • Example products: Blueprint Peptide Hair Serum lists sh-Polypeptide-86 (INCIDecoder); Vegamour GRO Hair Serum, Nécessaire The Scalp Serum, Sesderma Seskavel and MartiDerm Hair System list the fusion form (INCIDecoder); listing is not endorsement.
  • Unregulated injectables: “Research peptide” follistatin sold for injection is unregulated, of unknown content and sterility, and is a different, riskier product category.
  • Compounding pharmacies: Not applicable; sh-Polypeptide-86 is a cosmetic ingredient supplied to formulators, not a compounded medication.

Practical Considerations

  • Time to effect: Hair cycles are slow. Other topical hair treatments need 3–4 months to change shedding and 6–12 months to change visible density; no timing data exist for sh-Polypeptide-86.
  • Common pitfalls: Replacing proven treatments; judging change in a mirror instead of standardized photographs; starting several new products at once; reading “supports hair vitality” marketing as a regrowth claim.
  • Regulatory status: A cosmetic ingredient in the United States and European Union, not approved or evaluated by the FDA (Food and Drug Administration) for hair loss. Products may lawfully claim only appearance benefits.
  • Cost and accessibility: Serums cost roughly $40–$120 per month (Blueprint Peptide Serum is $119 per 50 mL), several times generic minoxidil. Insurers rarely cover cosmetic hair treatments, so no payer incentive favors either option.
  • Marketing language: “Follistatin” branding implies bioactivity that has not been independently verified for the recombinant ingredient in finished products.

Interaction with Foundational Habits

  • Sleep: No direct interaction; the ingredient has no known effect on sleep. Indirectly, chronic sleep loss raises stress hormones linked to shedding. Evening application on a dry scalp, allowed to dry 10–15 minutes before bed, limits transfer to pillowcases.
  • Nutrition: Indirect and supportive. Adequate protein, iron, zinc and vitamin D sustain follicle function, and crash dieting can trigger shedding that would mask any effect. The ingredient depletes no nutrients and needs no specific diet.
  • Exercise: Indirect. Vigorous exercise raises circulating follistatin, largely from the liver (Hansen et al., 2011); the scalp relevance of this is unknown. Heavy sweating can dilute a leave-on serum, so application after the post-workout shower preserves contact.
  • Stress management: Indirect. Chronic stress can precipitate telogen effluvium, masking any benefit or mimicking failure. No effect of sh-Polypeptide-86 on cortisol or the stress response is known.

Monitoring Protocol & Defining Success

Baseline testing before starting establishes a reference point and excludes treatable causes of hair loss. It combines standardized scalp photographs of the crown, part line and temples under fixed lighting with a small panel of blood tests for iron stores (ferritin), thyroid function (TSH, thyroid-stimulating hormone) and vitamin D. Women with irregular periods, acne or excess facial hair add androgen testing. A dermatologist scalp examination records any existing lesions.

Ongoing monitoring follows a set cadence: photographs at 3 months and 6 months, then every 6 months; blood tests repeated at 6–12 months only if a baseline value was abnormal, otherwise yearly; and a scalp skin examination every 12 months. Success is defined as stable or increased hair count in the same photographed area at 6 months, compared with the expected decline in untreated pattern hair loss.

Biomarker Optimal Functional Range Why Measure It? Context/Notes
Standardized scalp photographs / target-area hair count No established target; stable or rising versus own baseline Objective efficacy endpoint Same lighting, part, hair length and camera distance; a clinic phototrichogram (hair counting from clipped-area photographs) adds precision
Ferritin 50–100 ng/mL Iron stores; low levels drive shedding Conventional lower limit 15–30 ng/mL; raised by inflammation, so pair with CRP (C-reactive protein, an inflammation marker)
TSH 0.5–2.5 mIU/L Thyroid dysfunction causes diffuse loss Conventional range 0.4–4.5 mIU/L; pair with free T4 (the main thyroid hormone); morning draw
25-hydroxyvitamin D 40–60 ng/mL Deficiency is linked to hair loss Conventional sufficiency threshold 20–30 ng/mL; retest 3 months after supplementation
Zinc (serum) 90–120 µg/dL Deficiency can cause shedding Conventional range 60–120 µg/dL; fasting morning sample preferred
Hemoglobin Women 13.5–15.0 g/dL; men 14.0–16.0 g/dL Detects anemia contributing to shedding Conventional lower limits 12.0 (women) and 13.5 g/dL (men); part of a complete blood count
Total testosterone (women with androgen signs) 15–40 ng/dL Excess androgen accelerates pattern loss Conventional range about 8–60 ng/dL; early-morning draw; pair with SHBG (sex hormone-binding globulin) and DHEA-S (an adrenal androgen)
Scalp skin examination No new or changing lesions Screens for skin cancer and dermatitis Dermoscopy (magnified skin examination) at baseline and yearly; every 6 months after prior skin cancer

Qualitative markers:

  • Daily shedding (hairs on pillow, brush or shower drain)
  • Ponytail thickness or part-line width
  • Scalp comfort: itch, redness, flaking or burning after application
  • Styling volume and how hair holds its shape
  • Lash or brow fullness where the ingredient is also applied

Emerging Research

  • No registered sh-Polypeptide-86 trials: A ClinicalTrials.gov search in September 2026 found no completed, ongoing or planned trial of sh-Polypeptide-86 or topical follistatin for any hair outcome. Independent trials would be needed to establish any effect.
  • Histogen HST-001 phase 1b/2a (completed, unpublished): Randomized, placebo-controlled trial in 36 men with pattern hair loss receiving three rounds of 20 scalp injections of a follistatin-containing mixture; primary endpoint was crown (vertex) hair count at week 18 (NCT04435847). It did not beat placebo (Histogen, 2021), weakening the case.
  • Hair Stimulating Complex in women: Phase 1 safety trial of the follistatin-containing mixture in 27 women with female pattern hair loss; status unknown and no results posted (NCT03662854).
  • Hair Stimulating Complex phase 1/2 in men: 56-participant trial planned for 2011–2012 comparing the mixture with culture medium; status unknown and no results posted (NCT01501617).
  • Follistatin gene therapy safety: Muscle gene transfer of follistatin in 6 men with Becker muscular dystrophy (an inherited muscle-wasting disease) reported no adverse effects (Mendell et al., 2015; NCT01519349), offering limited reassurance on systemic follistatin exposure.
  • Retracted longevity gene-therapy study: A mouse study reporting that follistatin gene delivery prevented age-related hair loss and extended lifespan was retracted (Jaijyan et al., 2022), removing one strand of support for follistatin in aging hair.
  • Follistatin-family proteins in androgen damage: A 2026 laboratory study found that follistatin-like 1, a related but distinct protein, worsened androgen-driven damage in human dermal papilla cells (follicle-base cells that direct growth) (Huang et al., 2026), cautioning against assuming the family is uniformly protective.
  • Skin-delivery science: Whether a 32 kDa protein reaches the follicle through intact skin remains the pivotal open question; skin-penetration limits for large molecules are well described (Bos & Meinardi, 2000), and penetration studies of finished products could strengthen or refute the topical rationale.

Conclusion

sh-Polypeptide-86 is a lab-made copy of follistatin, a natural protein that blocks signals holding hair follicles at rest. The idea behind it is sound in animals: follistatin shapes when follicles grow, and its levels fall with age in mice. For health-focused adults looking for options that act on the growth cycle rather than on hormones, that makes it an appealing concept.

The human evidence is thin and indirect. The only hair results come from an injected mixture that combined follistatin with other growth signals, tested by the company that developed it. A small early study was encouraging, and a later, larger one did not clearly beat a placebo. No study has tested the cosmetic ingredient itself on the scalp, and it is uncertain whether a protein this large passes through intact skin. Much of the public discussion comes from brands that sell serums containing it or from sites that sell competing products.

Known risks are modest for a scalp serum: possible irritation, plus theoretical concerns from animal work about wound healing, skin immune cells and skin cancer that remain unconfirmed in people. The more concrete cost is time: pattern hair loss progresses, and options with stronger evidence exist.

On current evidence, sh-Polypeptide-86 is an unproven cosmetic ingredient with a plausible biological rationale, low expected harm and no demonstrated regrowth effect in people.

Top - Benefits - Risks - Protocol