Melanotan 2 is a lab-made ring of seven amino acids, built at the University of Arizona to copy a natural skin-darkening hormone. It was tested in a few small human studies and never approved. Doctors have reported melanoma and blood vessel harms in people who injected it.
Why scientists study it
- It switches on four receptors at once: MC1R, MC3R, MC4R and MC5R. MC1R makes skin produce pigment. MC3R and MC4R act in the brain on eating and sexual arousal.
- It came before PT-141 (bremelanotide), a compound aimed more narrowly at the brain. The FDA later approved PT-141 for low sexual desire in women who have not reached menopause.
- People who used it without approval have had recorded harms: case reports of melanoma and erupting moles, kidney infarction, and a steady pattern of gut, heart and blood vessel side effects.
Three studies to know
Dorr et al., 1996 · Life Sciences
Dorr and colleagues ran the key phase I pilot at the University of Arizona in healthy male volunteers. Two of the three men had darker skin after injections under the skin. Nausea, a flushed face and erections that came on by themselves capped the dose. It is still the fullest forward-looking human dataset. Read the paper
Wessells et al., 2000 · Urology
Wessells and colleagues ran a controlled trial in men whose erection problems had a physical cause. Melanotan 2 injected under the skin improved erections and the men’s own rating of sexual desire. The work set out the reasoning that led to the PT-141 (bremelanotide) program. Read the paper
Habbema et al., 2017 · International Journal of Dermatology
Habbema and colleagues reviewed the safety of unregulated α-MSH analogues. They gathered case reports of melanoma, atypical and erupting moles, gut symptoms, heart and blood vessel events such as kidney infarction and heart attack, priapism, and reactions where the needle went in. They judged the harms to be consistent and to matter clinically. Read the paper
Safety and legal status
- Recorded harms in people who used it without approval include published case reports of melanoma, kidney infarction, heart attack and other heart or blood vessel events, priapism, and moles that erupt or darken. Several separate skin research groups reported them.
- It is not approved for any use by the FDA, EMA, MHRA or TGA. The FDA has warned the public against unlicensed melanotan injections. The World Anti-Doping Agency lists it under class S0 and bans it in and out of competition.
- Strictly for in vitro and laboratory research use. It is not meant for human use, diagnosis or treatment.
Related compounds
- PT-141: Lab-made peptide (bremelanotide) that acts on the brain, tested for low sexual desire.
- GHK-Cu: Copper-bound chain of three amino acids, tested in cells and animals for skin and wound repair.
- Glutathione: The main antioxidant inside cells, made of three amino acids and tested in small human trials.