Biotinoyl tripeptide-1 and Acetyl tetrapeptide-3

Biotinoyl tripeptide-1: biotinyl-GHK, "Procapil" (trade name of a blend with apigenin and oleanolic acid). Acetyl tetrapeptide-3: Ac-KGHK, "Capixyl" (trade name of a blend with red-clover extract / biochanin A). Related: copper tripeptide-1 (GHK-Cu, #5) in hair products

Skin & cosmetic

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Summary

Class: Biotinoyl tripeptide-1: GHK with a biotin (vitamin B7) molecule attached. Acetyl tetrapeptide-3: synthetic tetrapeptide Lys-Gly-His-Lys, acetylated. Both are sold only as blends with plant-derived 5α-reductase inhibitors
Mechanism: Peptides are meant to anchor and nourish the follicle (matrix proteins, microcirculation); the plant partners (apigenin, oleanolic acid; biochanin A) are meant to reduce DHT formation and inflammation around the follicle
Routes studied: Topical scalp (lotions, serums, shampoos)
Dose range reported: Procapil: 3% of finished formula in studies. Capixyl: 5% in treatment studies, 0.5–2.5% for "maintenance" products. GHK-Cu in hair products: typically 0.05–1%
Half-life: Not applicable topically; no systemic data
Storage: Finished products: room temperature, protect from light. Raw blends: refrigerate
Regulatory status: Permitted cosmetic ingredients; no medicinal approval for hair loss anywhere (minoxidil and finasteride remain the only widely approved drugs)

Doses are as reported in studies or by the community — never recommendations.

1What it is

Hair-loss cosmetics have borrowed the peptide idea from skin care and combined it with botanical ingredients that mimic, weakly, the action of the drug finasteride.

Biotinoyl tripeptide-1 is GHK (#5, #185) with biotin attached instead of copper. It is the peptide half of "Procapil", a blend developed by a French ingredient company in which it is combined with apigenin (a flavonoid from citrus, meant to improve blood flow) and oleanolic acid (from olive leaf, a reported 5α-reductase inhibitor).

Acetyl tetrapeptide-3 is a four-amino-acid synthetic peptide and the peptide half of "Capixyl", developed by a Canadian/French ingredient company, where it is combined with red-clover extract rich in biochanin A (an isoflavone that inhibits 5α-reductase ).

Both peptides are synthetic; biotin and GHK are natural components.

2How it's thought to work

Follicle anchoring. Both peptides are claimed to increase synthesis of extracellular-matrix proteins (collagen, laminin) in the dermal papilla and the follicle's connective sheath, improving how firmly the hair is held and how well the papilla is supplied.

5α-reductase inhibition (the plant half). Oleanolic acid and biochanin A reduce conversion of testosterone to DHT ; DHT shrinks follicles in androgenetic (pattern) hair loss. These are much weaker than finasteride and their skin penetration is uncertain.

Anti-inflammatory. Micro-inflammation around the follicle is thought to accelerate pattern hair loss; both blends claim to reduce inflammatory markers (IL-8 and others) in culture.

Prolonging anagen. The net claim is a higher proportion of hairs in the growth phase (anagen) versus the resting phase (telogen) — the "A:T ratio" that most of the studies measure.

Proposed: copper and signal peptides applied to the scalp, aimed at pushing a resting follicle back into its growth phase. A resting follicle is short and shallow with no shaft; a growing one is deeper with a bulb. The evidence is mostly small manufacturer studies.Schematic — not to scale

Because the peptide and the botanicals are never tested separately, no effect can be attributed to the peptide alone.

3What the research shows

Dermal papilla and matrix protein synthesis (in vitro)

Manufacturer data for both blends report increased collagen/laminin expression and reduced DHT formation and inflammatory markers in cultured dermal papilla cells. Not independently replicated.

Procapil, anagen/telogen ratio

A manufacturer pilot of 3% Procapil lotion in about 35 men over 4 months reported that roughly two-thirds showed a meaningful improvement in A:T ratio versus placebo (phototrichogram), and a 6-month open-label study reported reduced hair fall in about 79% of participants — the latter with no control group. Summarised in an independent 2025 narrative review (Bikash 2025, Int J Trichology), which rates this evidence as low-level. [1]

Capixyl, anagen/telogen ratio

A manufacturer study of 5% Capixyl in about 30 men over 4 months reported a 46% increase in A:T ratio versus a 33% decrease on placebo, and a biochanin-A-containing formulation was reported to perform comparably to 3% minoxidil (Bikash 2025, review of manufacturer files). Small, manufacturer-run, male-only. [1]

Graded A (one trial, with caveats)

Procapil + Capixyl + Redensyl combination versus 5% minoxidil

A 24-week randomised trial in about 106 participants with androgenetic alopecia compared a serum containing all three blends with 5% minoxidil and reported better results on physician assessment and photographic evaluation for the combination †. A single trial, three blends at once, qualitative endpoints in part, and industry links not excluded — the review that cites it calls for replication.

Women, other hair-loss types, long-term

Most studies are male-only and 4–6 months. No data in alopecia areata, telogen effluvium or scarring alopecia beyond anecdote.

Graded C/B

GHK-Cu in hair

See #5: follicle enlargement in animal and ex-vivo human follicle work; limited clinical support.

4Reported side effects and interactions

Literature-reported

Both blends are reported as well tolerated in trials; mild scalp irritation or itching occasionally. No systemic adverse effects reported — none expected from trace topical peptides and botanicals.

Community-reported

scalp itch or dryness with some formulas (often alcohol-based), greasy residue; occasional initial shedding attributed to the product (more plausibly natural cycling). Many report no visible change.

Theoretical. red-clover isoflavones are weak phytoestrogens; systemic absorption from a scalp lotion is very low and no hormonal effect has been reported. No concern specific to the peptides.

Interactions. none established. Commonly layered with minoxidil without reported problems; no study of the combination's efficacy.

Markers researchers commonly monitor

No blood markers are relevant to the topicals themselves. For anyone investigating hair loss, standard baseline tests clinicians order: ferritin, TSH, vitamin D, zinc, and (in women) androgens — to exclude treatable causes before attributing results to a cosmetic. Hair-specific measures:

Marker	Why it's watched
Standardised scalp photographs (same parting, lighting, camera distance) every 4–8 weeks for at least 6 months
Phototrichogram or trichoscopy (hair density and anagen:telogen ratio)	the trial endpoint, available at trichology clinics.
Hair-shed counts (e.g. 60-second comb test)	crude but trackable at home.

Free for everyone. Safety information is never behind a paywall.

5Formulation and handling

Both blends are supplied as liquid concentrates (water/glycol or butylene-glycol base) for addition to leave-on scalp lotions and serums at 3–5%; lower levels in shampoos, where contact time is too short for much effect. Heat-sensitive, added in cool-down. Not by consumers; products are used daily on the scalp for a minimum of 3–4 months before any assessment is meaningful. No calculator applies.

6Commonly studied alongside

Minoxidil (comparator and co-use), Redensyl (a non-peptide botanical blend), GHK-Cu (#5), caffeine, saw palmetto, rosemary oil, ketoconazole shampoo; acetyl hexapeptide-1 (#187) in grey-hair products.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	Cosmetic ingredients. "Promotes hair growth" or "treats hair loss" is a drug claim (only minoxidil and finasteride are approved); products use wording such as "reduces appearance of thinning"
European Union	CosIng-listed; permitted. Hair-growth claims are limited to cosmetic wording
United Kingdom	Same as EU
Australia	Permitted cosmetic ingredients; therapeutic hair-regrowth claims would require TGA listing
South Africa	Permitted in cosmetics
Sport (WADA)	Not listed

8Open questions

Does either peptide contribute anything beyond the botanical 5α-reductase inhibitors? Never tested separately.
Independent replication of the combination-versus-minoxidil trial, with quantitative hair counts and disclosed funding.
Efficacy in women and in non-androgenetic hair loss — essentially unstudied.
Durability after stopping — unreported.

9References

1Bikash C (2025). Topical alternatives for hair loss: beyond the conventional. Int J Trichology 17(1):13–19. PubMed · DOI
2Randomised 24-week trial of a Procapil/Capixyl/Redensyl combination versus 5% minoxidil in androgenetic alopecia (2023–2024) [authors, journal to verify before citing]. PubMed
3Pickart L, Vasquez-Soltero JM, Margolina A (2015). GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. Biomed Res Int. (GHK background) PubMed · DOI
4Trüeb RM (2015). The impact of oxidative stress on hair. Int J Cosmet Sci. (micro-inflammation rationale) PubMed · DOI
5Manufacturer technical files for Procapil (3%) and Capixyl (5%) (undated; not peer-reviewed). PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

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11Page history

31 Oct 2026Profile published — awaiting medical review

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