Acetyl hexapeptide-1

Melitane (trade name), MSH-mimetic hexapeptide, Ac-Nle-Ala-His-D-Phe-Arg-Trp-NH₂, also sold under hair-care trade names for grey hair

Skin & cosmetic

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Summary

Class: Synthetic hexapeptide analogue of the core sequence of α-melanocyte-stimulating hormone (α-MSH); a melanocortin-1 receptor (MC1R) agonist
Mechanism: Activates MC1R on melanocytes to increase melanin (especially the brown-black eumelanin) and, in the same pathway, dampens inflammatory signalling and supports DNA-repair responses
Routes studied: Topical only (face, body, scalp/hair)
Dose range reported: Ingredient-manufacturer studies: 1–5% of the commercial solution in finished products, corresponding to peptide in the parts-per-million range †; marketed for "tan enhancement", redness reduction and, in hair products, grey-hair repigmentation
Half-life: Not applicable topically; no systemic data
Storage: Finished products: room temperature, protect from light. Raw material: refrigerate
Regulatory status: Permitted cosmetic ingredient; no medicinal approval (contrast with afamelanotide, an approved injectable α-MSH analogue)

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

1What it is

Acetyl hexapeptide-1 is the cosmetic cousin of the melanotans. α-MSH is a 13-amino-acid hormone made in skin and pituitary that tells melanocytes to produce pigment; its "message" sits in the central His-Phe-Arg-Trp sequence. In the 1980s medicinal chemists made a far more potent version by swapping two amino acids (norleucine for methionine, D-phenylalanine for L-phenylalanine), giving [Nle4, D-Phe7]-α-MSH — afamelanotide / Melanotan I. Acetyl hexapeptide-1 takes that same modified core, trims it to six residues and caps the ends, producing a small peptide intended for topical use. A French cosmetic-ingredient company sells it as "Melitane"; a hair-care version is sold under a separate trade name for grey hair.

It is a synthetic molecule, but a direct mimic of a natural hormone, which is what makes it more biologically "loaded" than most cosmetic peptides.

2How it's thought to work

MC1R activation → pigment. Binding MC1R raises cyclic AMP in melanocytes, switching on MITF and the melanin enzymes (tyrosinase, TRP-1, TRP-2) and shifting production toward eumelanin. Topically, the aim is to amplify the tan from UV exposure and to add colour to the skin.

Anti-inflammatory and photoprotective. α-MSH signalling in keratinocytes and immune cells is anti-inflammatory and supports repair of UV-induced DNA damage; the ingredient manufacturer promotes this as a "soothing" and "sun-preparing" action.

Hair pigment. Melanocytes in the hair bulb also carry MC1R; the grey-hair claim rests on stimulating residual melanocytes, which does not address the loss of melanocyte stem cells that underlies most greying.

Penetration. A hexapeptide without a lipid tail penetrates intact skin poorly; the ingredient manufacturer uses encapsulation. How much reaches basal-layer melanocytes is unknown.

Proposed: a cosmetic peptide marketed for the same SNARE-interference idea as argireline, with the same unresolved question about penetration.Schematic — not to scale

3What the research shows

Melanin production (in vitro)

Manufacturer data report dose-dependent increases in melanin in cultured melanocytes and in reconstructed skin models, and reduced inflammatory cytokine release in keratinocytes. Consistent with the known pharmacology of the parent sequence (Dorr 2000, Photochem Photobiol — the injectable analogue's human tanning study, for context). [1]

Tan enhancement and skin colour (topical)

Manufacturer volunteer studies cited in trade material report increased skin pigmentation (colorimeter readings) after several weeks of application with or without UV exposure, and reduced UV-induced redness, in small groups †. Not peer-reviewed; vehicle-controlled design not confirmed.

Graded B/—

Grey hair repigmentation

Ingredient-manufacturer studies of a scalp lotion report an increase in the proportion of pigmented hairs over 3–4 months in small volunteer groups †. No independent trial; the biology (loss of follicular melanocyte stem cells) makes a large effect unlikely.

Not gradednot applicable

Comparison with injectable analogues

Afamelanotide (Melanotan I) and Melanotan II have human data as injectables (see their profiles). Acetyl hexapeptide-1 has no systemic data and is not the same molecule; community claims that the topical is "Melanotan in a cream" overstate both potency and penetration.

4Reported side effects and interactions

Literature-reported

Manufacturer safety testing reports no irritation or sensitisation at use levels. No independent data.

Community-reported

modest, slow darkening with UV exposure in some users; many report no visible effect. Occasional reports of uneven darkening of existing freckles or spots.

Theoretical. this is the one cosmetic peptide in this batch with a hormone-mimicking mechanism. Systemic MC1R/MC3R/MC4R effects (nausea, flushing, appetite, blood-pressure and sexual effects) are documented for injectable analogues, not for the topical, and penetration is probably too low — but it has not been measured. Stimulating melanocytes in people with many atypical moles or a melanoma history is a theoretical concern raised for all melanotropins; dermatologists generally advise caution. Darkening of pre-existing moles would also make skin checks harder.

Interactions. none established. Pairing with tyrosinase inhibitors (brighteners) is pharmacologically contradictory.

Markers researchers commonly monitor

No blood markers apply to topical use. Practical measures:

Marker	Why it's watched
Colorimeter or standardised photographs of a treated and untreated area	the only way to tell peptide effect from ordinary tanning.
Mole mapping / photographs of existing moles before starting, because any melanotropin can darken naevi and change their appearance
Sun exposure diary	the confounder that dominates any pigment measurement.
Forearm patch test before first use

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

5Formulation and handling

Supplied as an aqueous solution, often liposome- or polymer-encapsulated; recommended 1–5% of finished product. Water-soluble; heat- and light-sensitive; added in the cool-down phase. Products are marketed as "tan accelerators", "after-sun" soothers and scalp lotions. Not by consumers. No calculator applies; this is not an injectable.

6Commonly studied alongside

Afamelanotide / Melanotan I and Melanotan II (the injectable analogues — different molecules, different risk), tyrosine (as a melanin precursor in tan accelerators), nonapeptide-1 (#188 — its pharmacological opposite), biotinoyl tripeptide-1 (#189, in grey-hair scalp products).

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	Cosmetic ingredient; "tan-enhancing" claims are tolerated as cosmetic; any claim to protect from UV would make it an unapproved sunscreen drug
European Union	CosIng-listed; permitted. EU authorities have warned that topical melanotropins must not be marketed as sun protection †
United Kingdom	Same as EU
Australia	Permitted cosmetic ingredient. Note that injectable melanotans are Schedule 4 and illegal to supply without prescription; the topical peptide is a different, permitted substance
South Africa	Permitted in cosmetics
Sport (WADA)	Not specifically listed; injectable melanotans are discussed but not on the Prohibited List as of 2026 †. A trace topical cosmetic is not a doping concern

8Open questions

Does the peptide reach basal melanocytes in intact human skin at an active concentration? Not measured.
Any independent, vehicle-controlled trial of pigmentation or redness? None found.
Effect on atypical moles or melanoma risk with long-term use — unknown, and unlikely ever to be tested at cosmetic scale.

9References

1Dorr RT et al. (2000). Increased eumelanin expression and tanning is induced by a superpotent melanotropin [Nle4-D-Phe7]-α-MSH in humans. Photochem Photobiol. (parent analogue, injectable) PubMed · DOI
2Abdel-Malek ZA et al. (2009). Melanocortins and the melanocortin 1 receptor: moving translationally towards melanoma prevention. Arch Biochem Biophys. PubMed
3Brennan R, Wells JSG, Van Hout MC (2017). The injecting use of image and performance-enhancing drugs (IPED) in the general population: a systematic review. Health Soc Care Community. (context on melanotan misuse, not the topical) PubMed · DOI
4Schagen SK (2017). Topical peptide treatments with effective anti-aging results. Cosmetics. DOI
5Manufacturer dossier (undated). Melitane: acetyl hexapeptide-1 pro-pigmenting biomimetic peptide (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

forum threads →

community protocols include this →

Threads and protocols are visible to members. Joining is free.

Self-reported side effects Phase 2

Not enough data yet. 0 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

31 Oct 2026Profile published — awaiting medical review

Licensed CC BY-NC-SA 4.0. Found an error? Report it · Editorial standards — corrections are logged here.