Melanocortin peptides

Members that reach MC1 darken skin. Scenesse’s label lists darker skin and new or darker moles (4% each) and recommends a full-body skin exam twice a year. Vyleesi’s reports dark patches in 1% of users at up to 8 doses a month but 38% after 8 daily doses, and Melanotan 2 can bring out new moles within days.

Nausea is common across the group: 40% vs 1.3% on placebo with bremelanotide, 19% vs 14% with the afamelanotide implant, and frequent in Melanotan 2’s small trials. Flushing affected 20% on bremelanotide.

Each bremelanotide dose briefly raises blood pressure, usually for up to 12 hours, and its label rules it out with uncontrolled high blood pressure or known heart disease. Melanotan 2 is nearly identical, so its page applies the same caution; one overdose case report described a racing heart and raised blood pressure.

Case reports describe melanomas in Melanotan 2 users, but no controlled study has tested the risk, so whether it raises it is unknown. Scenesse’s EU label urges special caution with a personal or family history of melanoma, inherited atypical-mole syndromes or past skin cancers.

The stack check flags any two of Melanotan 1, Melanotan 2 and PT-141, since all act on melanocortin receptors. Vyleesi’s label warns that doses close together can add up on blood pressure and that more frequent dosing raises the risk of dark skin patches. KPV isn’t flagged.

Vyleesi’s label advises birth control and stopping if pregnancy is suspected; in dogs, bremelanotide raised pregnancy loss. Scenesse’s EU label rules out pregnancy and breastfeeding and asks for birth control during treatment and for 3 months after. Melanotan 2 and KPV have no human safety data.

Only two uses are approved: the afamelanotide implant for EPP and bremelanotide for acquired low desire in premenopausal women. Injected powders sold for tanning aren’t Scenesse and fall outside its label, Melanotan 2 was never approved, and KPV has no human data.

Afamelanotide works mainly through MC1, the pigment receptor. Bremelanotide activates MC1, MC4, MC3, MC5 and MC2, in that order of potency, with MC1 and MC4 most relevant at its dose. Melanotan 2 binds several receptors strongly in lab tests. KPV likely doesn’t act through melanocortin receptors at all.

Scenesse is a 16 mg implant a clinician places under the skin every 2 months. Vyleesi is a 1.75 mg autoinjector used as needed, at most once in 24 hours; its label doesn’t recommend more than 8 doses a month. In community use, melanotan powders are injected daily at first, then 1–3 times a week, and KPV is taken daily.

Afamelanotide: pigment and light tolerance, with implant-site reactions and nausea. Bremelanotide: desire, with nausea, flushing and blood pressure rises. Melanotan 2: tanning plus spontaneous erections and less appetite, with case reports of priapism (an erection lasting hours) and muscle breakdown. KPV: lower inflammation in animal models, with no human side-effect data.

Melanotan 1 and PT-141 aren’t banned: as approved drugs they fall outside WADA’s S0 rule. Melanotan 2 and KPV aren’t named on the 2026 list but likely fall under S0, which bans drugs with no current human approval anywhere.