Melanotan II Research Peptides

Melanotan II is a synthetic cyclic analogue of alpha-melanocyte-stimulating hormone. It activates multiple melanocortin receptors and has been studied for pigmentation and erectile responses.

A three-person Phase I pilot reported increased pigmentation in two participants after monitored Melanotan II exposure. That is direct human evidence of a pigmentation effect, but it is far too small to establish a reliable cosmetic tanning response or long-term safety.

The research does not establish that. Melanotan II can stimulate pigmentation, but the tiny direct human tanning study did not show that it prevents UV damage or skin cancer, and long-term cosmetic safety has not been established.

Melanomas have been reported during or after melanotan use, including Melanotan II cases, but case reports cannot prove causation and several patients also had UV, sunbed or other melanoma risk factors. The risk magnitude is therefore unresolved rather than proven absent or proven causal.

Yes, melanocytic changes have been reported. Published case reports describe darkening of existing lesions and the appearance of new or atypical naevi after melanotan exposure, although case reports cannot provide an incidence rate.

Small double-blind crossover studies in men with erectile dysfunction found substantially more erectile activity after Melanotan II than placebo, and one study also reported higher sexual-desire scores. These experiments did not establish a licensed treatment.

A controlled human weight-loss benefit has not been established. Reduced appetite appeared as a side effect in early human research, but that is not evidence of sustained weight loss or a safe obesity treatment.

Early controlled studies commonly reported nausea, yawning, stretching, appetite reduction, somnolence or spontaneous erections. Later case reports describe rarer serious events including priapism, rhabdomyolysis with systemic toxicity, renal infarction and posterior reversible encephalopathy syndrome.

A validated human Melanotan II plasma half-life was not identified in the peer-reviewed human studies reviewed. Half-life values for afamelanotide or estimates repeated on commercial peptide sites should not be presented as measured Melanotan II data.

No validated human nasal Melanotan II pharmacokinetic or efficacy study was identified. Australian regulator testing in 2026 also found large variation in the measured amount of Melanotan II across five marketed nasal-spray bottles.

The UK Government states that Melanotan II injections and pens are considered medicinal products, so legal medicine supply requires an appropriate marketing authorisation. Cosmetic-only nasal tanning products without medical claims may fall outside the MHRA's medicines remit. That does not mean the nasal products are MHRA-approved or proven safe.

No. Afamelanotide, sometimes historically called Melanotan I, is the active ingredient in the approved SCENESSE implant. Bremelanotide, also called PT-141, is the active ingredient in Vyleesi. Melanotan II is a separate cyclic melanocortin agonist and evidence from those approved medicines should not be transferred to it.