Melanotan 1 vs Melanotan 2 compares two lab-made versions of alpha-MSH, the hormone that darkens skin. In short: Melanotan 1 (afamelanotide) is a linear peptide that is FDA-approved as the Scenesse implant for a rare light-sensitivity disorder, while Melanotan 2 is a shorter, ring-shaped peptide that also acts in the brain, causing erections and nausea, and is not approved anywhere.[1][4] Both are sold online as unregulated tanning products, which dermatologists have linked to new moles and melanoma.[9]
Melanotan 1 vs Melanotan 2 at a glance
| Melanotan 1 (afamelanotide) | Melanotan 2 | |
|---|---|---|
| Structure | Linear peptide[4] | Ring-shaped (cyclic), shorter peptide[4] |
| Main receptors | MC1 on pigment cells[1] | MC1 in skin plus MC3 and MC4 in the brain[4] |
| Main effects | Skin darkening[5] | Tanning, erections, nausea, appetite changes[6][4] |
| Approved product | Scenesse 16 mg implant for EPP (FDA, 2019)[2] | None |
| Strongest evidence | Two randomized phase 3 trials[3] | Small University of Arizona studies, 1996 to 2000[6][7] |
| Spin-off drug | None | Led to PT-141 (bremelanotide)[4] |
How each one works
Both peptides were created at the University of Arizona as more stable, more potent versions of alpha-MSH.[4]
Melanotan 1 binds the melanocortin 1 (MC1) receptor on pigment cells, increasing melanin, the brown pigment in skin, without sun exposure.[1] In a 1991 JAMA trial in 28 healthy men, a course of 10 injections under the skin produced a tan, while placebo did not.[5]
Melanotan 2 is shorter and cyclic, which makes it potent and long-lasting. It reaches MC3 and MC4 receptors in the brain as well as MC1 in the skin, so it affects sexual function and appetite too.[4] Its sexual effects were discovered by accident during tanning research.[19]
Evidence quality
Melanotan 1 (afamelanotide)
- Erythropoietic protoporphyria (EPP): in two randomized phase 3 trials published in 2015, afamelanotide implants increased pain-free time in direct sunlight compared with placebo (a median of 69.4 vs 40.8 hours over 6 months in the US trial, and 6.0 vs 0.8 hours over 9 months in the EU trial).[3]
- Vitiligo: in 55 adults, adding monthly implants to narrowband UV-B light therapy restored more pigment than light therapy alone (48.6% vs 33.3% at day 168), but it is not approved for this use.[20]
- Tanning: early injection studies showed tanning that lasted weeks after the last dose, with occasional stomach upset and facial flushing.[21]
Melanotan 2
All human trials were small:
- Tanning: in a 1996 pilot, 2 of 3 men tanned after five low doses; spontaneous erections and nausea also occurred.[6]
- Erectile dysfunction: in a 1998 crossover trial, it produced erections in 8 of 10 men with psychological causes.[7] In men with physical causes, erections followed 12 of 19 injections versus 1 of 21 placebo injections.[8]
Side effects and safety
Melanotan 1 (Scenesse label). The most common side effects in trials were implant-site reactions (21%), nausea (19%), sore throat, cough and tiredness. The label warns about serious allergic reactions and darkening of moles and freckles, and recommends a full-body skin exam twice a year.[1]
Melanotan 2. Its known risks come from case reports, since it never went through large trials:
- Moles and melanoma: new and darkening moles within 24 hours of a single injection,[14] and melanomas reported in users.[13]
- Priapism: painful erections lasting hours.[15]
- Muscle breakdown and toxicity: rhabdomyolysis and stimulant-like symptoms after injection.[16]
- Brain swelling: a case of posterior reversible encephalopathy syndrome.[17]
A 2017 dermatology review of both peptides noted that a causal link to melanoma has not been proven but advised caution, citing changes in existing moles and new atypical moles.[9] Product quality is a further risk: a European lab analysis of melanotan II sold online found impurities.[18]
Legal status
- US: Scenesse is a prescription drug for adults with EPP, approved October 2019.[2] It must be implanted by a trained health professional.[1] FDA treats other melanotan products as unapproved new drugs, and one seller was convicted of a felony.[12]
- UK: the MHRA says unauthorised medicines cannot be sold and that it has removed melanotan products from the market for more than 10 years.[11]
- Denmark: the medicines agency calls melanotan an illegal product with undocumented effects.[10]
- Sport: neither is named on WADA’s 2026 list; unapproved melanotan products likely fall under the S0 category.[23]
Social media fuels much of the interest: a 2025 dermatology study analyzed melanotan content trending on TikTok.[22]
Melanotan 2 vs PT-141 and approved options
Melanotan 2’s effect on sexual function led researchers to develop PT-141 (bremelanotide), a related peptide,[4] which FDA approved in 2019 as Vyleesi.[24] If sexual function is the goal, our PT-141 vs Viagra comparison and the PT-141 profile cover the approved routes, and our guide to the best peptides for sexual health grades every option by evidence.
Nasal sprays and “tanning jabs”
Products sold online include Melanotan 2 injections and nasal sprays, which are a different thing from the regulated Melanotan 1 implant.[11] The Danish Medicines Agency warns that the effects of these products are undocumented and their side effects unstudied,[10] and the MHRA has repeatedly removed them from the UK market.[11]
Questions to discuss with a clinician
- Do I have a diagnosed light-sensitivity condition such as EPP, where afamelanotide is approved?
- If I am interested in sexual-function treatment, which approved options suit me?
- Do I have many moles, a history of melanoma, or a family history of skin cancer?
- Who will check my skin, and how often?
The verdict
Melanotan 1 and Melanotan 2 are close chemical cousins with very different track records. Melanotan 1, as the regulated Scenesse implant, is an approved, trial-tested treatment for one rare disorder. Melanotan 2 never got past small early studies and has a growing list of case-report harms. Neither is approved for cosmetic tanning, and unregulated products of either carry unknown purity and dose. For more, visit the sexual health peptides hub.
This is general information, not medical advice.
