In plain language
Melanotan II is a synthetic melanocortin peptide that both darkens skin and can increase sexual arousal. It is widely sold online as an unregulated injectable for tanning, but it is not an approved medicine and has been flagged by regulators over safety concerns.
What it is explored for
Melanotan II is best known for its dual reputation, studied for both sunless tanning and sexual arousal through the melanocortin system. That combination is what makes it so widely discussed, though it is unapproved and regulators have raised real safety concerns worth taking seriously.
- Skin pigmentation and sunless tanning
- Sexual desire and arousal
- Appetite and satiety signaling
- Energy and mood via melanocortin pathways
- Body composition and metabolic interest
- Central nervous system melanocortin effects
These are areas of active interest and reported use, not proven outcomes. This peptide carries a limited evidence rating, see the evidence summary below for how strong the science actually is.
How it works
Melanotan II is a non-selective melanocortin receptor agonist, meaning it activates several melanocortin receptors rather than just one. This breadth explains its mixed effects.
- Pigmentation via MC1. Activates the MC1 receptor on pigment cells to increase skin tanning.
- Arousal via MC4. Activates the MC4 receptor in the brain, which is linked to sexual arousal (the basis of the related drug PT-141).
- Broad melanocortin effects. Its non-selective action also contributes to side effects such as nausea and appetite changes.
The arousal pathway it shares with PT-141 is what led to the development of that more targeted, approved drug.
Evidence summary
There is some human data showing Melanotan II increases pigmentation and can affect sexual arousal, and it inspired the approved drug PT-141. However, it is sold as an unregulated product of uncertain purity, has notable side effects, and has been the subject of regulatory safety warnings, so its overall evidence and safety picture is limited.
Reported safety & side effects
Melanotan II is not approved and has real safety concerns. Reported issues include nausea, flushing, darkening and changes of moles, and rare more serious reactions. Products are typically unregulated, so purity and dosing are uncertain.
Stacking notes
Full stacking guideMelanotan II affects blood pressure and the cardiovascular system. Combining it with stimulants or other vasoactive compounds deserves caution and monitoring.
General educational guidance, not medical advice. Combination evidence is limited; any stack should involve a qualified clinician.
Frequently asked
Is Melanotan II FDA-approved?
No. It is not approved by the FDA and is sold as an unregulated product. Regulators in several countries have issued warnings about its safety.
How is it related to PT-141?
Both act on melanocortin receptors. Melanotan II hits several of them broadly, while PT-141 (bremelanotide) was developed as a more targeted version and is an approved drug for low sexual desire.