Skin-brightening cosmetic peptide (Nonapeptide-1 / Melanostatine-5)
A synthetic nine-amino-acid peptide that blocks the skin-darkening signal in pigment cells, reducing pigmentation; used as a cosmetic ingredient, not an approved drug.
- Class
- Cosmetic peptide / MC1R antagonist
- Status
- Cosmetic ingredient; no approved therapeutic indication in any jurisdiction
- Best-supported effect
- Competitive antagonism at MC1R in ex vivo melanocyte assay systems, proposed to blunt α-MSH-driven cAMP / MITF / tyrosinase activation (in vitro / ex vivo evidence only)
- Main caveat
- No independent peer-reviewed clinical trials; human efficacy evidence is limited to manufacturer-sponsored cosmetic panel data that has not been independently replicated
A researcher, an agent, or an algorithm wrote down the sequence and picked a target to hit.
An AI model like OpenFold3 or AlphaFold built a 3D structure and scored how well it fits the binding site.
A second contributor repeated the computation on their own hardware and the scores matched.
A chemistry service or a researcher ordered the sequence, it was manufactured, and mass spectrometry confirmed the right molecule was produced.
A binding or activity measurement confirmed that it actually does what the computer predicted — or didn't.
Snapshot
Class: Cosmetic peptide / MC1R antagonist
Evidence tier: In vitro / assay evidence
Status: Cosmetic ingredient; no approved therapeutic indication in any jurisdiction
Best-supported effect: Competitive antagonism at MC1R in ex vivo melanocyte assay systems, proposed to blunt α-MSH-driven cAMP / MITF / tyrosinase activation (in vitro / ex vivo evidence only)
Main caveat: No independent peer-reviewed clinical trials; human efficacy evidence is limited to manufacturer-sponsored cosmetic panel data that has not been independently replicated
What this is
Nonapeptide-1 is a synthetic nine-amino-acid peptide developed and marketed primarily under the trade name Melanostatine-5 by Lucas Meyer Cosmetics (now part of IFF). It was designed as a structural analog of α-melanocyte-stimulating hormone (α-MSH) to act as a competitive antagonist at the melanocortin 1 receptor (MC1R) on melanocytes. By occupying MC1R without activating it, Nonapeptide-1 is proposed to reduce the α-MSH-driven signaling cascade that upregulates tyrosinase expression and melanin synthesis — an upstream mechanism distinct from direct enzyme inhibition (hydroquinone, kojic acid, Decapeptide-12) or melanosome-transfer blockade (niacinamide). It is used exclusively in topical cosmetic formulations and is not an injectable therapeutic. The mechanistic rationale is biologically coherent, but the human efficacy evidence base is thin, largely manufacturer-sponsored, and not independently replicated in peer-reviewed controlled trials.
Evidence map
| Evidence layer | Grade | What it supports |
|---|---|---|
| Human | Anecdotal / manufacturer panel | Manufacturer-sponsored cosmetic panel studies reporting reductions in skin pigmentation indices over several weeks; no independent peer-reviewed RCTs measuring objective endpoints (MASI score, melanin index, photographic evaluation) are identified |
| Animal | Weak | Nonapeptide-1-specific animal skin studies are sparse in the peer-reviewed literature per available sources; mechanistic rationale draws on the broader MC1R antagonism literature |
| In vitro / ex vivo | Moderate | MC1R binding and antagonism of α-MSH-driven cAMP / MITF / tyrosinase signaling in melanocyte assay systems; primary basis for the mechanistic claim |
| Computational | None identified | No docking, structure prediction, or model score identified |
| Mechanism | Plausible | The α-MSH / MC1R / cAMP / MITF / tyrosinase axis is well-established melanogenesis biology; MC1R antagonism as a depigmenting strategy is mechanistically coherent, but the bridge from receptor-level mechanism to demonstrated topical human efficacy is not established in independent literature |
independent clinical replication, head-to-head comparisons against established brightening agents, and rigorous quantification of skin penetration across commercial vehicles are essentially absent from the peer-reviewed literature. The current evidence base is largely manufacturer-sponsored.
Claim check
| Claim | Verdict | Evidence layer | Confidence |
|---|---|---|---|
| Antagonizes MC1R and reduces α-MSH-driven cAMP / MITF / tyrosinase activation | Supported (in vitro / ex vivo) | In vitro | Medium — assay-based; penetration to melanocyte MC1R in intact human skin not established in source |
| Reduces UV-induced hyperpigmentation in topical cosmetic use | Weak / preliminary | In vitro; manufacturer cosmetic panels | Low — per available sources manufacturer data only; no independent peer-reviewed RCT with objective endpoints identified in source |
| Evening of skin tone in cosmetic formulations | Weak / preliminary | In vitro; manufacturer cosmetic panels | Low — same manufacturer-sponsored panel evidence base; independent controlled evidence absent per source |
| Equivalent to or superior to established brighteners (hydroquinone, tranexamic acid, Decapeptide-12, cysteamine) | Not established | None | Low — published literature explicitly notes head-to-head comparisons are absent from the peer-reviewed literature |
Assay conditions
This section reports conditions described in available literature for ex vivo and manufacturer cosmetic assay contexts. It does not establish animal or human clinical dosing.
| Context | System | Condition | Timepoint | Endpoint | Limitation |
|---|---|---|---|---|---|
| Ex vivo melanocyte assay | Melanocyte cultures; manufacturer-described models | Topical concentration as specified by ingredient supplier; exact assay concentrations not individually extracted in source | Multi-week protocol; exact durations not individually extracted | Pigmentation index; α-MSH-driven cAMP / MITF / tyrosinase markers | Manufacturer-sponsored; skin penetration from commercial vehicles not independently validated in source |
| Manufacturer cosmetic panel | Human cosmetic panel (small, manufacturer-sponsored) | Low percentage topical formulation in serum or cream vehicle; exact concentration not individually extracted | Several weeks per source description; exact duration not individually extracted | Skin pigmentation index reduction per source narrative | No objective endpoints (MASI score, melanin index, photographic evaluation) reported in independent peer-reviewed publications per source |
Assay limitations
- The in vitro and ex vivo evidence base is primarily manufacturer-sponsored; independent peer-reviewed studies validating MC1R antagonism efficacy for Nonapeptide-1 specifically are not identified.
- Skin penetration data — the dose of Nonapeptide-1 that reaches the dermo-epidermal junction from a realistic topical vehicle — is not established in available literature. Without this, in vitro antagonism data does not translate to predictable clinical efficacy.
- Assay systems do not establish that receptor-level antagonism in melanocyte cultures translates to clinically meaningful hyperpigmentation reduction in controlled human trials.
- No human safety or toxicology data beyond manufacturer-reported topical tolerability are identified.
- Per available sources, occasional local irritation, redness, or dryness at cosmetic use levels in manufacturer tolerability data; independent safety assessment is not identified.
- Long-term effects of sustained topical MC1R antagonism — including potential effects on UV-induced DNA damage repair pathways, since MC1R signaling is linked to photoprotection as well as pigmentation — are uncharacterized in available literature.
Regulatory status
| Region / body | Status | Notes |
|---|---|---|
| US (FDA) | Cosmetic ingredient | Regulated under FDA cosmetic law; not approved as a drug; not approved to treat melasma, post-inflammatory hyperpigmentation, or any medical indication; cosmetic label claims limited to appearance-related language (brightening, evening tone) |
| EU | Cosmetic ingredient permitted | per available sources as listed in the CosIng database under INCI name Nonapeptide-1; no drug approval |
| UK | Cosmetic ingredient permitted | per available sources; permitted under INCI name; not independently refreshed in this card |
| Canada | Cosmetic ingredient permitted | per available sources; permitted under INCI name; not independently refreshed in this card |
| Japan | Cosmetic ingredient permitted | per available sources; permitted under INCI name; not independently refreshed in this card |
| WADA | Not listed as prohibited | Per available sources, topical cosmetic peptides with negligible systemic exposure are not listed on the WADA Prohibited List and are not a realistic doping concern; per available sources, not independently refreshed in this card |
No approved therapeutic status identified. This card describes a topical cosmetic ingredient, not an approved medicine.
Mechanism
Nonapeptide-1 is a nine-amino-acid structural analog of α-MSH (a 13-amino-acid peptide cleaved from pro-opiomelanocortin) designed to bind the melanocortin 1 receptor (MC1R) — a Gs-protein-coupled receptor expressed on melanocytes — as a competitive antagonist rather than an agonist.
In the normal melanogenesis pathway, α-MSH binds MC1R, activates adenylate cyclase, raises intracellular cAMP, and drives PKA-mediated phosphorylation of CREB. Phosphorylated CREB upregulates MITF, the master transcription factor for melanogenic genes including tyrosinase (TYR), TRP-1, and TRP-2, shifting the melanocyte toward eumelanin production. UV exposure, inflammatory mediators, and hormonal inputs converge on this α-MSH / MC1R / cAMP / MITF axis.
By competitively occupying MC1R without triggering Gs signaling, Nonapeptide-1 is proposed to reduce α-MSH-driven cAMP elevation, dampen CREB/MITF activation, and lower baseline tyrosinase expression. This upstream mechanism is distinct from direct tyrosinase enzyme inhibition (hydroquinone, kojic acid, Decapeptide-12), melanosome-transfer inhibition (niacinamide), or melanocyte cytotoxicity.
Key mechanistic questions unresolved in the published literature include: the actual binding affinity of Nonapeptide-1 at human MC1R, its selectivity versus related melanocortin receptors (MC2R–MC5R, which are involved in adrenal, cardiovascular, and appetite signaling), the effective dose reaching melanocyte MC1R from realistic topical vehicles, and whether receptor-level antagonism in ex vivo melanocyte assay systems scales to clinically meaningful hyperpigmentation improvement in controlled human trials.
Target confidence: Inferred from the broader α-MSH / MC1R mechanistic literature and manufacturer-described assay data. Direct binding affinity data for Nonapeptide-1 at human MC1R is not individually extracted from peer-reviewed sources in this card. Receptor selectivity versus MC2R–MC5R has not been characterized in the attached evidence.
Chemistry
| Field | Value |
|---|---|
| Common name | Nonapeptide-1 |
| INCI name | Nonapeptide-1 |
| Trade name(s) | Melanostatine-5; Melanostatine |
| Developer | Lucas Meyer Cosmetics (now IFF) |
| Length | 9 amino acids |
| Topology | Linear |
| Origin type | Synthetic; designed as a shortened α-MSH analog |
| Parent molecule | α-MSH (13-mer; endogenous, cleaved from POMC) |
| Key modification | Shortened 9-residue analog engineered for MC1R competitive antagonism rather than agonism |
| Full amino-acid sequence | not individually extracted's available literature |
| Sequence confidence | Needs review — sequence not individually extracted; identifier-level description only |
| Formulation context | Topical only; used in serums, creams, and finished brightening formulations at supplier-specified concentrations; not for injection and not manufactured to injectable standards |
Open questions
- Independent clinical validation: No peer-reviewed independent randomized controlled trial measuring objective endpoints (MASI score, melanin index, photographic evaluation) for Nonapeptide-1 as an isolated active has been identified in available literature. Controlled human trial replication is the most critical evidence gap.
- Skin penetration quantification: The dose that reaches the dermo-epidermal junction from commercial topical vehicles has not been independently established. Without this, in vitro MC1R antagonism data may not translate to in-use topical efficacy across formulations.
- MC1R binding affinity and receptor selectivity: Published binding affinity (Ki / IC50) data at human MC1R and selectivity data versus MC2R–MC5R for Nonapeptide-1 specifically are absent from available literature.
- Long-term MC1R antagonism effects: The effects of sustained topical MC1R blockade on UV-induced DNA damage repair pathways — since MC1R signaling is linked not only to pigmentation but also to photoprotection — are not characterized in available literature.
- Head-to-head comparisons: Rigorous comparative evidence against established brightening agents (hydroquinone, tranexamic acid, Decapeptide-12, cysteamine) in controlled trials is absent from available literature.
- Independent replication of manufacturer data: The current evidence base is manufacturer-sponsored. Independent academic or clinical replication would be required to confirm efficacy claims beyond anecdotal cosmetic panel reporting.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.8418987393379211 | boltz-2 |
| ranking score | 0.8184587359428406 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 0.828 | global PDE — lower = better |
| disorder | NaN | fraction disordered |
▸3-letter notation
▸recipeboltz-2 1.0
| parameter | value |
|---|---|
| model | boltz-2 1.0 |
| weights | — |
| hardware | nvidia_nim_api |
| mlx version | — |
| python | — |
| random seed | — |
| msa strategy | none |
| diffusion samples | 1 |
| runtime | — |
| predicted by | mlx@peptide |
| predicted at | 2026-04-24 |
▸citationbibtex
@peptide{pep10763,
sequence = {FRWGKPVG},
target = {mc1r},
author = {peptidemodel},
year = {2026},
status = {computed}
}