Melanotan II: effects and risks of an unapproved peptide
Clinical review pending
What early studies and case reports show about melanotan II, skin pigmentation and possible risks.
What is melanotan II?
Melanotan II is a synthetic cyclic peptide that activates several melanocortin receptors: MC1R, MC3R, MC4R and MC5R. It is sometimes called the “Barbie drug.” The approved medicine bremelanotide was developed from its structure. Melanotan II itself is sold through unofficial channels as an injection for skin tanning and sexual arousal. It is not an approved medicine. Source
How does it work?
The proposed effects mainly involve two receptors. MC1R on skin cells promotes pigment production and tanning. MC4R in the brain is involved in sexual arousal and appetite regulation. Findings on sexuality and appetite come predominantly from animal experiments and early pharmacological studies. The mechanism establishes neither the efficacy nor the safety of uncontrolled use for these purposes.
Is melanotan II FDA-approved?
No. Melanotan II is not FDA-approved. The agency has issued warning letters about injectable tanning products containing melanotan. Its compounding nomination was withdrawn. The FDA subsequently removed the substance from Category 2 in April 2026 and lists it as nominated but withdrawn 1. The approved melanocortin products Scenesse, for a rare photosensitivity disorder, and Vyleesi, for low sexual desire in certain women, are separate, regulated medicines. Their approvals do not apply to melanotan II.
What does the research show?
The source article cites no controlled human trials supporting use for tanning or increasing libido. The clinical literature mainly consists of case reports and medical warnings. New or changed moles and darkening of pigmented lesions have been described after melanocortin tanning injections 2 3. Poison centers and dermatological sources also report nausea, flushing and other effects. These reports are not controlled trials. The uncertain quality of unregulated products adds another concern.
The first human data came from a 1996 pilot study 4 involving three healthy men. Its results are summarized in the table.
The small study was conducted for drug development and does not establish that products obtained through unofficial channels are safe. A particularly serious skin finding was described later: in a case report 5, a fair-skinned 20-year-old woman developed melanoma after using the substance alongside tanning beds. A temporal association in a single case does not, by itself, establish causation.
Studies at a glance
| Finding | Result |
|---|---|
| Increased pigmentation | In 2 of the 3 men |
| Spontaneous erections | Lasted 1 to 5 hours |
| Mild nausea | Occurred at most doses |
| Grade II drowsiness and fatigue | In 1 of 2 men whose dose was increased to the highest level |
References provided in the source article
Sources: case reports of pigmented-lesion changes after melanocortin tanning injections (Cardones and Grichnik, Archives of Dermatology, 2009, DOI: 10.1001/archdermatol.2008.623 2 ; Cousen et al., British Journal of Dermatology, 2009, DOI: 10.1111/j.1365-2133.2009.09362.x 3 ), indexed on PubMed; and FDA warning communications on injectable tanning products.
Provenance and editorial review status
Adapted for Nutrient Desk from the source article. The claims and source attributions in the original text still require clinical review. This draft has not been cleared for indexing.