Melanotan 2 and its reported aphrodisiac effects

Melanotan 2 is a synthetic peptide built to imitate a natural hormone called α‑MSH. Although the original goal behind its development was tanning without sun exposure, scientists stumbled on something unexpected: MT‑2 also seemed to affect sexual desire and performance. That unintended effect helped change the way the peptide was viewed — not just as a cosmetic agent, but as something that might influence libido and arousal. 

How Melanotan 2 works in the body

MT2 binds to various melanocortin receptors (MC1, MC3, MC4, MC5). The tanning effect comes largely from MC1 activation in skin. The effects on sexual desire and arousal are thought to come mostly from MC4 (and possibly MC3) receptors in the brain.   That activation can influence brain circuits tied to sexual motivation and genital arousal, rather than acting purely on blood flow or peripheral tissues like many “sexual‑performance” drugs. 

What early studies found — erotic side‑effects by accident

•In one of the first reports, researchers noticed that human volunteers receiving Melanotan 2 tanning injections sometimes got spontaneous erections. That happened even without visual or sexual stimulation. 

•A more thorough study involving men with erectile dysfunction (ED) — both psychological and organic causes — used a placebo‑controlled, crossover design. With MT‑2, many of these men developed penile erections during the 6‑hour monitoring period, even though there was no erotic stimulus. 

•These findings suggested that MT‑2 might “trigger” sexual arousal centrally (via the brain), not just as a side effect of a vascular mechanism. 

•In reviews of human and animal data, the consensus was that melanocortin signalling influences sexual function — for both sexes. MT‑2 came out as a kind of prototype demonstrating that effect. 

Why some people think of it as a “sexual performance enhancer”

Because of these unexpected but repeatable effects — erections without stimulus, increased sexual desire, reports of heightened sensitivity or arousal — many people began to view MT‑2 as more than “just tanning.” For some, it became attractive as a dual‑purpose peptide: a bit of a glow, plus a potential libido boost.

At the same time, unlike typical medications for erectile dysfunction that work on blood flow (for example via vascular changes), MT‑2 works centrally. That means it acts on brain pathways associated with arousal, libido, and sexual motivation — a different approach. 

Safety and why it never became mainstream

Despite the promising findings, Melanotan 2 Tanning Injections were never approved as a mainstream sexual performance drug. Part of the reason is that, while some studies showed strong effects in controlled settings, the evidence was limited (small sample sizes, short‑term). Side effects like nausea, yawning, flushing or other discomforts were common. 

https://www.sciencedirect.com/science/article/abs/pii/S0090429500006804?utm