Melanotan II
July 4, 2023Incremental
4/10
Purrptide digest
Melanotan II was originally developed as a sunless tanning agent — it activates melanocortin receptors that trigger melanin production, no sun required. During trials, researchers noticed an unmissable side effect: a significant increase in libido. That accidental discovery led directly to the development of PT-141 as a dedicated sexual dysfunction drug. The FDA never approved Melanotan II itself, citing safety concerns including potential effects on existing moles. It remains a grey-market product with real risks alongside its real effects.
What this means for you
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If you care about weight/health
The unapproved status reflects genuine safety concerns, not just bureaucracy — including darkening of existing moles. Worth taking seriously.
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If you're a clinician
If patients mention using this for tanning, the mole-darkening effect is worth monitoring given the melanocyte-stimulating mechanism.
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If you're a researcher
The accidental libido discovery during tanning trials directly seeded an entire separate drug development program (PT-141).
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If you follow biotech
Never achieved approval itself, but indirectly created a successful approved drug (PT-141) as a spinoff. An odd but real commercial legacy.
WE
Wessells et al.
University of Arizona
For the nerds
Melanocortin receptor agonists, penile erection, and sexual motivation
International Journal of Impotence Research · DOI: 10.1038/sj.ijir.3900472
Read full paper on PubMed →