Bremelanotide vs Melanotan I
It is an injection for women who have low sexual desire. Two trials in 1,267 women found small gains on questionnaires, and about 40% of users felt sick. Sold as a safe way to tan without sun. It darkened skin in a 65-person trial. The approved version is a different product for a rare sun-pain disease.
Both sit at grade B: some human evidence. Bremelanotide: FDA approved. Melanotan I: Not approved.
Evidence
BSome human evidence
BSome human evidence
Human studies cited
Animal or cell studies cited
Why the grade
Approval rests on the two RECONNECT phase 3 trials, which randomized 1,267 premenopausal women and met their co-primary endpoints on desire and distress questionnaires. The effect sizes were small, the number of satisfying sexual events did not increase, dropout for nausea was high, and an independent reanalysis questioned the validity of the outcome questionnaires. Approved on RCTs but with surrogate questionnaire endpoints and contested benefit is grade B.
For the tanning use it is sold for, the evidence is one placebo-controlled trial in 65 fair-skinned volunteers that measured melanin density and UV damage markers, a surrogate for sunburn protection. The approved use in erythropoietic protoporphyria rests on two randomized placebo-controlled trials totaling 168 patients. The tanning use has one trial with surrogate endpoints, which is B; no trial has tested cosmetic tanning in the general population or compared it with sunscreen.
FDA
FDA approved
Bremelanotide is FDA-approved and sold as Vyleesi, a self-administered subcutaneous autoinjector, approved in June 2019 for premenopausal women with acquired, generalised hypoactive sexual desire disorder (HSDD). It is not approved for men or for postmenopausal women.
Not approved
Melanotan I is the same molecule as afamelanotide, which the FDA approved in 2019 as the Scenesse implant for adults with erythropoietic protoporphyria. Injectable 'Melanotan I' sold online for tanning is not approved by the FDA for any use and is sold as a research chemical.
Sold for
Bremelanotide is marketed as an on-demand injection for low sexual desire in women and is sold online, often as PT-141, as a libido booster for anyone.
Melanotan I is sold as the 'safer' tanning peptide, the one that became a real drug, promising a tan without sun and protection against burning.
Studies say
Two randomized trials in 1,267 women showed statistically significant but small improvements in questionnaire scores for desire and distress, no increase in satisfying sexual events, and nausea in about 40% of users (grade B).
A 65-person placebo-controlled trial showed more melanin and less UV damage in fair skin, and two trials in 168 porphyria patients led to approval of the implant, so the evidence is grade B for tanning and the approved product is a different formulation for a rare disease.
Class
MC4R agonist
MC1R agonist
Route
Injection
Injection