Melanotan 2 (MT-2)

Melanotan II is a small ring-shaped chain of seven amino acids built in a laboratory to imitate alpha-MSH (alpha-melanocyte-stimulating hormone), the natural signal your body uses to tell pigment cells in the skin to make more of the brown pigment melanin. It was designed at the University of Arizona in the late 1980s, and because the redesign made it far longer-lasting than the natural hormone, it also switches on the other melanocortin receptors, the docking points in the brain that influence erections, sexual interest and appetite. Two things follow from that history. First, the clinical work that exists was run mostly on erectile dysfunction rather than on tanning, and it stopped in the early 2000s when the developers moved on to a shorter fragment that became PT-141 (bremelanotide). Second, nothing carrying the name melanotan II has ever been approved by a medicines regulator in any country, so every vial and nasal spray on the market is an unlicensed product of unverified content. A different and genuinely approved drug, afamelanotide (brand name SCENESSE), is sometimes confused with it, but that is a separate linear peptide given as an implant for a rare light-sensitivity disease.

• Cosmetic tanning, which is what almost everyone buying it actually wants, and which rests on a single-blind, placebo-controlled pilot in three volunteers
• Erectile dysfunction, the only use with double-blind placebo-controlled human data, all of it from small 1990s crossover studies
• Sexual desire and arousal, which those same studies measured as a secondary outcome in men
• Appetite suppression, an effect driven by the melanocortin-4 receptor that has been shown in animals but not in any human weight trial located
• Reducing sunbed or sun exposure time, a rationale users report that no trial has tested and that the melanoma case reports argue against

Think of your pigment cells as a factory that only runs when a work order arrives from head office, and sunlight is normally what sends the order. Melanotan II is a forged work order that arrives whether the sun sends one or not, and it is written in ink that does not fade, so the factory keeps running for hours. The catch is that the same forged memo gets delivered to several other departments by mistake, which is why the erection and appetite offices in the brain start acting on it too. It also reaches every pigment cell you own, including the ones already clustered inside a mole.

1. First hoursIn the 1996 phase I pilot study the injection was followed by a stretching and yawning complex that lined up with spontaneous erections lasting intermittently for one to five hours. Nausea and facial flushing, if they happen, usually arrive in this same window.
2. Day 1-21Two of the three volunteers in that pilot study showed increased pigmentation of the face and upper body, measured by quantitative reflectance one week after two weeks of escalating alternating-day subcutaneous doses had ended. That is the entire published human tanning timeline, and it used a different schedule from the cheatsheet figures on this page.
3. Week 2-4This is when users in the 2021 qualitative forum study describe the colour building, typically alongside continued sunbed use. No controlled trial has measured how dark the tan gets, how evenly, or how long it lasts after stopping.
4. Month 1-3Darkening of existing moles and the appearance of new atypical moles are reported in this range in the dermatology case literature, including one report of multiple new atypical naevi within a week of only two injections.
5. Month 3+There is no published human follow-up beyond a few weeks of dosing. The longest-horizon reports in the literature are individual melanoma cases rather than planned follow-up, so nothing is known about repeated seasonal use.

• Nausea is the most consistently reported effect across the human studies; in the 2000 International Journal of Impotence Research report of 20 men, severe nausea occurred in roughly 13 percent of subjects at the 0.025 mg/kg dose
• A stretching and yawning complex, described in both the 1996 pilot and the 1998 crossover trial, often immediately before an erection
• Spontaneous erections without sexual stimulation, which happened in 8 of 10 men in the 1998 double-blind crossover study and are frequently unwanted outside a clinic
• Priapism, a painful erection that will not resolve: a 2019 BMJ Case Reports case required cavernosal aspiration, irrigation and intracavernosal phenylephrine, and the patient had still not recovered erectile function at four weeks
• Decreased appetite and facial flushing, both noted in the early trials
• Darkening of existing moles and eruptive new atypical moles, reported repeatedly in the dermatology literature
• Melanoma has been reported in association with use, including a 20-year-old woman who self-injected for three to four weeks alongside sunbed tanning (Dermatology, 2014) and a 22-year-old woman who developed an oral mucosal malignant melanoma after using a melanotan II nasal spray (International Journal of Oral and Maxillofacial Surgery, 2025)
• Rhabdomyolysis with renal dysfunction: a 39-year-old man who injected 6 mg, six times the commonly quoted starting dose, reached a creatine phosphokinase of 17,773 IU/L and needed intensive care (Clinical Toxicology, 2012)
• Renal infarction has been attributed to it in at least one case report with literature review (CEN Case Reports, 2020)
• The United States Food and Drug Administration also lists posterior reversible encephalopathy syndrome and sympathomimetic toxidrome among the serious adverse events described in published case reports

• You are pregnant, trying to conceive, or breastfeeding, as no reproductive safety data exist for this peptide at all
• You have a personal or family history of melanoma or any skin cancer, or you have many moles, atypical moles, fair skin that burns easily, or a history of heavy sunbed use
• You have any current or past cancer diagnosis, given that the mechanism is direct stimulation of pigment cell proliferation
• You have sickle cell disease, leukaemia, a clotting disorder, or you take any drug that raises priapism risk, because of the reported priapism and vascular events
• You have kidney disease or a history of rhabdomyolysis, or you intend to combine it with hard training or stimulants
• You are unwilling to have a dermatologist map your moles before and during use, or you are not working under a physician who knows what you are taking

• Treating the colour as sun protection. Users in the 2021 forum study commonly kept using sunbeds while injecting, and the melanoma case reports describe exactly that combination; a melanotan tan has never been shown to reduce ultraviolet damage
• Skipping a baseline mole check. Because the drug drives pigment cells everywhere, a dermatologist needs a before picture to tell an ordinary change from a dangerous one, and after starting it is too late to get one
• Escalating the dose to speed up the tan. The rhabdomyolysis case injected 6 mg in a single shot, six times the quoted starting dose, and ended up in intensive care
• Assuming a nasal spray is the gentler option. The 2025 oral mucosal melanoma case involved a nasal spray, and the dose absorbed by that route is completely uncontrolled
• Mixing it up with its relatives. Melanotan I (afamelanotide) is a different, approved implant for a rare disease, and PT-141 (bremelanotide) is a separate approved drug derived from this peptide; neither one's data belong to melanotan II
• Careless handling. Reconstitute with bacteriostatic water, keep the vial refrigerated and out of light, and remember that none of this addresses the underlying problem that the content and purity of an unlicensed vial are unknown