Afamelanotide vs PT-141
An implant that lets people with a rare sun-pain disease stay in daylight longer. Trials in 168 adults show it works for that, but none show it works for tanning. 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.
Afamelanotide has the stronger evidence, grade A (strong human evidence) against grade B for PT-141. Afamelanotide: FDA approved. PT-141: Not approved.
Evidence
AStrong human evidence
BSome human evidence
Human studies cited
Animal or cell studies cited
Why the grade
Two randomized, double-blind, placebo-controlled trials in 168 adults with EPP (94 in the United States, 74 in the European Union) showed more pain-free hours in sunlight, and a 117-patient post-authorisation cohort followed for about two years confirmed the effect in routine practice. Consensus guidelines recommend it for preventing phototoxic symptoms. The evidence is strong for EPP and nonexistent for the tanning use the compound is also known for.
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
FDA approved
Afamelanotide is FDA-approved and sold as Scenesse, a subcutaneous implant, approved in October 2019 to increase pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria (EPP). The European Medicines Agency authorised it for the same disease in 2014.
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
Afamelanotide is best known as the first drug for EPP, a rare disease in which sunlight causes burning pain, and in its earlier life as a candidate 'sunless tan' because it darkens skin.
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
Randomized trials show it lengthens the time EPP patients can spend in sunlight without pain, which earns grade A for that indication; there are no trials supporting cosmetic tanning.
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
MC1R agonist
MC4R agonist
Route
Implant
Injection