What Is Melanotan II? The Tanning Peptide and Its Risks

Melanotan II is non-selective: it activates several melanocortin receptors at once, which is why it has such a wide range of effects.

• MC1R (skin): stimulates melanocytes to produce dark eumelanin, causing tanning.
• MC3R and MC4R (brain): affect sexual arousal and appetite, which explains increased libido and reduced hunger.
• Other receptors: contribute to side effects such as nausea and flushing.

Tanning. Small early human studies from the University of Arizona showed that Melanotan II increased skin pigmentation, including in people who tan poorly. These studies were small and short.

Sexual function. Small studies in men reported spontaneous erections and increased desire. That finding led to PT-141, which went through full clinical development instead.

Skin cancer protection. The original hope was that a tan without UV exposure would protect skin. That has never been shown for Melanotan II. In practice, many users combine it with sunbed or sun exposure to “activate” the tan, which increases UV damage rather than reducing it.

Commonly reported short-term effects include nausea, facial flushing, reduced appetite, yawning and stretching, spontaneous erections, and fatigue.

Moles and melanoma. The biggest concern is skin. Published case reports describe new moles, rapid darkening of existing moles, and cases of melanoma in people using Melanotan II. Dermatologists also warn that darker, changing moles make early skin cancer harder to spot. Case reports cannot prove cause and effect, but they are the reason for repeated warnings.

Rare serious events. Isolated case reports describe kidney damage, muscle breakdown (rhabdomyolysis) and priapism. Product contamination and incorrect dosing from unregulated sellers add further risk.

In July 2026, the Skin Cancer Foundation issued a warning advising people to avoid injectable and nasal tanning drugs and to use sunless self-tanners instead.

No. Melanotan II is not approved by the FDA or any other major regulator. Health agencies in the UK, Australia and elsewhere have issued public warnings against buying it online.

In April 2026, the FDA moved this substance out of its “Category 2” table of compounding ingredients that may present significant safety risks and into a separate table of substances whose nominations were withdrawn by the nominators. That move is not a finding that the substance is safe or effective, and it does not place it on the 503A Bulks List.

Why the difference matters. Afamelanotide and bremelanotide are each more focused versions of the same idea, and both went through full clinical trials for narrow medical uses. Melanotan II hits all of these receptors at once and was never tested to approval standards.

Safer alternatives for a tan. Dihydroxyacetone (DHA) self-tanners darken only the top layer of skin, do not involve UV exposure, and do not act on hormone receptors.

Products sold as Melanotan II by research suppliers are laboratory chemicals, not medicines. They are not made under drug manufacturing rules, so quality varies a lot between vendors. If you are evaluating a Melanotan II supplier for lab research, these are the checks that matter:

• Batch-specific COA: the certificate should match the lot number on your vial, not a generic sample.
• Independent lab: testing should come from a named third-party lab, ideally with a way to verify the report online.
• Identity, not just purity: HPLC purity alone does not confirm the right molecule; look for mass spectrometry (MS) identity confirmation.
• Endotoxin and sterility results: these matter for any injectable research material.
• Correct fill amount: the measured content should be close to the labeled milligrams.

Our Trusted Sources page lists vendors we track, with current community codes. Our guide to reading a certificate of analysis explains each line of a COA.

• Melanotan II is a synthetic α-MSH analog that causes tanning, increased libido and reduced appetite.
• It activates several melanocortin receptors at once, causing nausea and flushing.
• Case reports link it to new and changing moles and melanoma.
• It is not approved anywhere, and the Skin Cancer Foundation warned against it in July 2026.
• Its relatives afamelanotide and PT-141 are approved for specific medical uses.

What is Melanotan II?

Melanotan II is a synthetic version of the hormone α-MSH that darkens the skin and also affects libido and appetite. It has never been approved as a drug.

Is Melanotan II safe?

Its safety has not been established. Case reports link it to new and changing moles and melanoma, and dermatology groups advise against using it.

Is Melanotan II legal?

It is not FDA-approved or approved by any major regulator. Agencies in several countries have warned against buying it online.

What is the difference between Melanotan I and Melanotan II?

Melanotan I (afamelanotide) is more selective for skin and is an approved drug for a rare light-sensitivity disorder. Melanotan II is non-selective and not approved.

Is Melanotan II the same as PT-141?

No. PT-141 (bremelanotide) was developed from Melanotan II to focus on sexual desire and is FDA-approved as Vyleesi.

• The Skin Cancer Foundation – Warning regarding Melanotan II (July 7, 2026)
• Dorr et al. (1996) – Evaluation of Melanotan-II, a superpotent cyclic melanotropic peptide, in a pilot phase-I clinical study
• Hjuler & Lorentzen (2014) – Melanoma associated with the use of melanotan-II, Dermatology
• FDA – Certain bulk drug substances for use in compounding that may present significant safety risks (updated April 22, 2026)