MELANOTAN II
A lab-made ring-shaped peptide sold online as a "tanning peptide". Never approved anywhere, and regulators warn against it.
What it's made of
Ac-[Nle] then a ring of D H [D-Phe] R W K, with a capped end. Almost identical to PT-141: only the very end is different.
Load it in the Peptide builder →Where it comes from
Copies part of alpha-MSH, the natural hormone that tells skin to make pigment. Developed at the University of Arizona in the 1980s and 1990s as a sunless tanning agent.
What it's studied for
- ◐ Reported
Early human tests were tiny: a 1996 safety test in 3 men and a 1998 trial in 10 men.
- ◌ Theory
It darkens skin by switching on the pigment receptor on skin cells. It also hits other receptors, which explains its effects on appetite and sexual response.
Studied for ≠ proven to work. Check the stamp.
What we don't know
- ?
Case reports describe new or changing moles, and some melanomas, in users. Whether the drug caused them is not proven.
- ?
Australia's regulator lists reported harms including kidney problems, muscle breakdown and painful erections that will not go away.
- ?
Online products are unregulated. Testing in Australia in 2026 found the amount inside varied more than two-fold between bottles.
Status
- Not approved anywhere. The UK regulator has warned against it since 2008.
- Vietnam: no registration found.
- Sport: not named on the 2026 list.