Quick answer: melanotan 2 results include real skin darkening, but the evidence comes from 3 men in one 1996 study and from doctors’ case reports. In that study, 2 of 3 men tanned after 5 low-dose injections.[1] Case reports since then describe new and darkening moles within a day of injecting, abnormal moles, several melanomas, and harms such as priapism and muscle breakdown.[4][9][13][14]
Melanotan 2 (melanotan II) is a synthetic version of the hormone that triggers skin pigment. It has never been approved anywhere. This page covers what it actually did in studies and in real-world case reports. See also our Melanotan 2 profile, Melanotan 2 dosage, Melanotan 1 vs Melanotan 2 and the sexual health and tanning peptides hub.
Tanning results in the only clinical study
The single tanning study was a pilot in 3 healthy men at the University of Arizona. They received 5 injections under the skin, every other day, at 0.01 to 0.03 mg per kg.[1]
- Tan: 2 of the 3 men had increased pigmentation on the face, upper body and buttocks one week after dosing ended, measured with a light-reflectance device and by eye.[1]
- Side effects: mild nausea at most doses, a stretching and yawning reaction, spontaneous erections lasting 1 to 5 hours after dosing, and sleepiness and fatigue at the highest dose in one man.[1]
Every participant in the melanotan II trials was a man, so there is no trial evidence on how it works in women, even though several case reports involve young women.[2][3][8][10] No larger tanning trial was ever published. How dark the tan gets, how long it lasts and whether it protects against sunburn were never measured in a controlled trial.
Sexual function results
The erections seen in the tanning study led to two small trials in men with erectile dysfunction, each using 0.025 mg per kg:
- Psychological causes: erections developed in 8 of 10 men; strong rigidity lasted an average of 38 minutes versus 3 minutes on placebo.[2]
- Physical risk factors: erections followed 12 of 19 injections versus 1 of 21 placebo doses, and sexual desire rose. Severe nausea followed 4 of 19 injections.[3]
Melanotan 2 was tested clinically for erectile dysfunction, and a newer analog, PT-141, was taken forward for development.[20]
Before and after: what case reports show
Online “before and after” photos show skin color. Dermatologists’ reports show what photos miss.
| Timing | What was seen |
|---|---|
| 24 hours after one injection | New moles and darkening of existing moles[4] |
| Within 1 week of two injections | Multiple new atypical moles[5] |
| About 1 week into daily injections plus tanning beds | Several existing moles “turned black”; five melanomas in situ found 2 to 3 weeks later[9] |
| Within 3 weeks, with sunbeds | All-over tanning and darkening moles; one enlarging groin mole was dysplastic[6] |
| After a 64-day course, with sunbeds | Brown patches on the gums and inner cheeks[7] |
| 3 months after a 3- to 4-week course, with sunbeds | Melanoma on the buttock of a 20-year-old woman with intensely pigmented skin[8] |
Does the tan fade?
The limited reports suggest it does. A 16-year-old girl’s skin was much paler, and her moles lighter, three months after she stopped injecting.[6] In the oral case, pigment on the inner cheeks had nearly gone a month after stopping, but gum pigmentation was still visible, though lighter, at three months.[7]
Moles and melanoma
The most concerning results involve moles.
- Melanoma cases: a 2017 review counted four published cases of melanoma arising from existing moles during or shortly after melanotan use. It said conclusive evidence of a link is lacking.[11]
- Newer cases: a 49-year-old man developed five melanomas in situ after melanotan 2, then melanotan 1, combined with tanning beds,[9] and a 22-year-old woman developed a melanoma inside her mouth after using a melanotan 2 nasal spray.[10]
- Sudden moles: a 2019 review of 179 people with eruptive moles found that drugs including melanotan, immune-suppressing medicines and chemotherapy were the suspected cause in 41%. 16% had at least one abnormal mole on biopsy, and five melanomas were reported.[12]
Many of these patients also used sunbeds, so the separate effect of melanotan is hard to judge.[8][9] The man with five melanomas also had a grandparent with melanoma and had been using testosterone from an unregulated source.[9] Doctors advise caution anyway.[11]
Other unwanted results
- Priapism: painful erections lasting hours. One man had not recovered erectile function four weeks after treatment.[13]
- Systemic toxicity: after injecting 6 mg, a man developed a racing heart, tremor, muscle breakdown and kidney injury, and spent 3 days in intensive care.[14]
- Kidney infarction: doctors reported a loss of blood supply to part of a kidney most likely linked to melanotan II.[15]
- Skin ulcers: a 65-year-old woman developed pyoderma gangrenosum, a rare ulcerating skin condition, at her injection sites; it took months of steroid treatment to heal.[16]
FDA also cites case reports of a brain-swelling syndrome (posterior reversible encephalopathy syndrome) and lists melanotan II among substances that may present significant safety risks.[19]
Why results vary so much
- Unknown dose: vials labeled 10 mg contained 4.32 to 8.84 mg in one lab analysis, with up to 5.9% unknown impurities.[17]
- Sunbeds: many users combine injections with sunbeds, and dermatologists list sunbed exposure among the hazards linked to melanotan use.[18]
- Self-reporting: a study of online forums found misinformation, dosing regimens and sunbed use among the main topics, and noted risks such as infection from unsafe injecting and contaminated products.[18]
What users report
The bottom line
Melanotan 2 can darken skin, but the only controlled evidence for that comes from 3 men, and the real-world results doctors report include changing moles and melanoma. It is not approved, and products are unregulated. For approved options for sexual function, see PT-141 vs Viagra and best peptides for sexual health. For pigment concerns, see peptides for hyperpigmentation.
Questions to ask a clinician
- Should I have a full-body skin check after using melanotan, and how often after that?
- Are any of my moles worth removing or photographing for comparison?
- If I have stopped, how long should I keep watching my moles?
- What are safer ways to look tanned?
This is general information, not medical advice.
