Melanotan II vs PT-141
It is an injection sold for a deep tan, less appetite and better erections. The only study had 3 men, and the rest is case reports of harm, including changing moles. It is sold online as a sex-drive booster, mostly to men. The approved form, bremelanotide, was tested in 1,267 women with small gains; for men there are only two small studies from 2004.
PT-141 has the stronger evidence, grade B (some human evidence) against grade C for Melanotan II. Neither is FDA approved.
Evidence
CAnimal and cell studies
BSome human evidence
Human studies cited
Animal or cell studies cited
Why the grade
The human evidence is a 1996 pilot phase 1 study in three men, plus case reports of melanoma and changing moles in users. No controlled trial of Melanotan II has been published for tanning or any other use.
For the approved use there are two randomized, placebo-controlled phase 3 trials (RECONNECT, 1,267 women combined), which is A-level evidence, though a re-analysis argues the effect on desire is small. For the use PT-141 is actually sold for online, libido and erections in men, the evidence is two small 2004 studies, one of a nasal spray that was later abandoned and one of an injection, so the compound as marketed sits at B.
FDA
Not approved
Not approved by the FDA for any use and sold as an unregulated gray-market product. Melanotan II was nominated for the FDA's list of substances compounding pharmacies may use and placed in Category 2 (significant safety risk); the nomination was withdrawn and the FDA removed it from that category in April 2026, with an advisory committee review planned, which does not make it legal to compound or sell.
Not approved
PT-141 is the development code for bremelanotide, which the FDA approved in June 2019 as Vyleesi for premenopausal women with acquired, generalized hypoactive sexual desire disorder. Products sold online as PT-141 are not Vyleesi, are not approved by the FDA for any use, and are sold as research chemicals, most often to men, a population the drug was never approved for.
Sold for
Melanotan II is the 'Barbie drug' of gym and tanning culture, sold online as an injectable that gives a deep tan, suppresses appetite, and improves erections.
PT-141 is sold on the gray market as a libido and erection booster for men and women that works through the brain instead of blood flow.
Studies say
A three-man pilot study in 1996 showed it darkens skin and causes erections and nausea, and the rest of the literature is case reports of harm, which is grade C evidence.
Two phase 3 trials support a modest effect on sexual desire in premenopausal women with HSDD, which is what the FDA approved; the evidence in men is two small 2004 studies, one nasal and one injected, from a program that was abandoned, and nausea affects about 40 percent of users.
Class
Melanocortin agonist (MC1R/MC3R/MC4R)
MC4R agonist
Route
Injection
Injection