"Tanning peptide" videos show a deep tan appearing in weeks with little sun. The substance behind them is almost always melanotan II, sold as an injection or nasal spray, occasionally melanotan I. This page sets out what they are, how they are meant to work, what regulators have said and when, and what has and has not been studied. It is not a guide to using them, and it gives no dose, route or source. Anyone weighing a tanning product that acts on their own skin is best served by a dermatologist or GP.
What the tanning peptides are
Both are synthetic copies of alpha-melanocyte-stimulating hormone (alpha-MSH), the body's signal for pigment cells to make dark eumelanin. Researchers at the University of Arizona built them in the 1980s and 1990s as a possible way to tan without ultraviolet damage.
- Melanotan I is a 13-amino-acid linear analogue. It later became afamelanotide, approved by FDA in October 2019 as Scenesse, an implant for adults with erythropoietic protoporphyria (EPP), a rare disorder in which light causes severe pain. That is its only approval, and it is not for tanning. Peptide Lexicon's melanotan I entry covers the molecule.
- Melanotan II is a shorter, ring-shaped analogue. It reaches more of the body's melanocortin receptors, which is why its human trials found effects well beyond skin colour. It is not approved anywhere. Peptide Lexicon's melanotan II entry covers the molecule.
How the pigment claim works
Pigment cells carry the melanocortin-1 receptor (MC1R). When alpha-MSH, or a copy of it, binds that receptor, the cells shift from light red-yellow pigment towards dark eumelanin. A 2000 study of melanotan I in seven volunteers measured higher eumelanin in skin biopsies after treatment (Dorr et al., PMID 11045725). That part is well documented. What is not documented is what else the same signal does to moles and pigment cells over months and years, which is the question the case reports below raise.
The human trials
PubMed tags eight melanotan records as clinical trials (a ninth match is a muscle-protein study). They split into two groups:
| Compound | Trials | What they studied |
|---|---|---|
| Melanotan I | Ugwu 1997 (3 men), Dorr 2000 (7 volunteers), Dorr 2004 (three small phase I studies), Fitzgerald 2006 | Tanning and pharmacokinetics; tanning with UV light; tanning in people with MC1R gene variants |
| Melanotan II | Dorr 1996 (3 men), Wessells 1998 and 2000 (three studies) | One pilot on tanning; then erections in men with erectile dysfunction |
The melanotan II pilot is the only tanning study of that compound PubMed indexes as a trial. Two of its three volunteers darkened on the face, upper body and buttocks. The researchers also reported nausea, fatigue and sleepiness at the higher level, and spontaneous erections lasting one to five hours after dosing (Dorr 1996, PMID 8637402). That side effect became the research direction: the next melanotan II trials, and the approved drug bremelanotide that grew from them, were about sexual function, not skin.
In the melanotan I trials, the tan peaked about a week after dosing stopped and was still present at three weeks, with "occasional gastrointestinal upset and facial flushing" (Ugwu 1997, PMID 9113347). One 2004 study found 47% fewer sunburn cells in treated volunteers' irradiated skin, in a group of four people (PMID 15262693).
These are phase I studies of a few volunteers each. None was designed to measure long-term safety, and none tested the products sold online today.
What regulators have said, with dates
| Regulator | Date | Position |
|---|---|---|
| FDA (US) | 30 Aug 2007 | Warning letter to Melanocorp: melanotan II is a new drug that cannot be sold without an approved application. The company's website had claimed it "could reduce skin cancer rates" and "could cure rosacea". A principal was later convicted of a felony (conspiracy) and FDA proposed permanent debarment (docket FDA-2015-N-4169). |
| FDA (US) | 8 Oct 2019 | Approves afamelanotide (Scenesse, NDA 210797) for EPP only. |
| MHRA (UK) | 17 Apr 2024 | Injectable melanotan II and pens are medicines; a nasal spray is a medicine "only if sold with claims to treat or prevent disease". "The sale, supply and advertising of unauthorised medicines is not permitted." Advice to users: stop and report side effects. 16 suspected adverse-reaction reports, 2012–2022 (FOI 24/274). |
Australia's Therapeutic Goods Administration has also issued consumer warnings about melanotan II and published product testing; its pages did not load for us on 24 September 2026, so this page does not quote them.
The safety record, counted by source type
On 24 September 2026, PubMed indexed 28 case reports for melanotan. Two are false matches (the abbreviation MT-II also means metallothionein II). The remaining 26 break down as follows:
| What the case report describes | Count |
|---|---|
| New, darkened or atypical moles | 9 |
| Melanoma (including one in the mouth after a nasal spray) | 3 |
| Other pigment change (nails, mouth lining) | 2 |
| Kidney infarction, rhabdomyolysis, brain swelling (PRES), priapism ×2, pyoderma gangrenosum | 6 |
| Drug identification, public-health and user-behaviour reports | 6 |
A case report describes what happened to one or a few people. It cannot show that the drug caused it, and several of the mole and melanoma reports involve people who also used sunbeds or other drugs. The full census, with each report named, is on our melanotan side effects page.
FDA's adverse-event database (FAERS) held about ten reports naming melanotan on the same date; eight of the nine naming melanotan II were marked serious, and the most common term was renal artery thrombosis. FAERS reports are unverified and can duplicate each other.
The moles question
Melanotan acts on the same pigment cells that form moles, so dermatologists have watched for changes. The case literature includes eruptive new moles within 24 hours of a single injection (Schulze 2014, PMID 24334249), darkening and changed dermoscopic patterns in existing moles (Mang 2012, PMID 23052015), and melanomas in users (Paurobally 2011, PMID 21564053; Vadner 2026, five melanomas in situ in one patient who also used tanning beds and anabolic hormones, PMID 42328529). Australian dermatologists described unregulated melanotan II use as "of public health interest" in 2017 (Adler et al., PMID 28905366). None of these reports can say how often such changes happen. A new or changing mole is a matter for a doctor to examine, whatever the cause.
The supply problem
Melanotan sold online is labelled "research use only" or sold as a nasal spray, and neither route involves a regulator checking what is in the vial. The MHRA notes that for unauthorised products "their contents are unknown and there are no safeguards that these products meet our standards for quality, safety or effectiveness". A 2024 forensic paper describes the work needed simply to identify what seized "Barbie drug" products contained (Deville et al., PMID 39302005).
What has never been tested
- No controlled trial of melanotan II in healthy people for cosmetic tanning, beyond the three-man 1996 pilot.
- No study measuring skin-cancer or mole outcomes over years, for either compound.
- No trial of the nasal-spray products sold to consumers.
- No trial of melanotan combined with sunbeds or deliberate sun exposure outside the small Arizona studies, which used measured UV doses.
For the regulated relative and its approved use, see the afamelanotide section above; for dosage figures as published, Peptifact's melanotan II dosage page reports them with sources. On this site, the peptides with a topical skin record are covered in peptides for skin, and sun protection with peptide ingredients in peptide sunscreen.