Melanotan ii

Mechanism of action

MT-II binds to and activates melanocortin receptors (GPCRs). Activation of MC1R in melanocytes increases eumelanin production through increased cAMP/PKA signaling and upregulation of melanogenic enzymes (e.g., tyrosinase), promoting pigmentation and potentially a greater pigmentary response to UV radiation. Central activation of MC3R/MC4R in the hypothalamus modulates satiety and energy expenditure and may influence circuits involved in sexual function. Activation of other subtypes (e.g., MC5R) may contribute to effects on exocrine secretions and other systemic phenomena. Its receptor non-selectivity explains the frequency of extra-cutaneous side effects.

Supported benefits

• Increased skin pigmentation (tanning) and melanogenesis, often even with reduced UV exposure compared with baseline (moderate)
• Pro-erectile effects and increased sexual response in some experimental settings (mediated by MC3R/MC4R) (limited)
• Reduced appetite/possible weight loss in experimental models and in some preliminary human studies (central melanocortin effect) (limited)
• Potential indirect photoprotection through increased eumelanin (does not replace sun protection; clinical evidence of reduced cancer risk has not been demonstrated) (emerging)

Safety & side effects

• Nausea and vomiting (common, dose-dependent)
• Headache, flushing, dizziness
• Increased blood pressure or changes in blood pressure/heart rate (variable)
• Diffuse and/or irregular hyperpigmentation; darkening of freckles and nevi
• Itching, injection-site reactions, risk of infection/inadequate sterility
• Priapism and/or prolonged erections (a potentially urgent event)
• Gastrointestinal disturbances (cramps, reduced appetite)
• Possible neuropsychiatric effects (anxiety/restlessness) reported anecdotally
• Risk related to uncontrolled products: contaminants, endotoxins, dosage not matching the label

FAQ

Is Melanotan II the same thing as afamelanotide?

No. They are related but different peptides: afamelanotide is more selective for MC1R and is a regulated drug for specific indications; MT-II is more non-selective (MC1R–MC5R) and is not approved for general clinical use.

Does the tan induced by MT-II protect against sunburn?

An increase in eumelanin may partially reduce susceptibility to sunburn in some individuals, but it does not eliminate UV damage or replace sunscreen, clothing, and limiting exposure. The protection is incomplete and variable.

Can it increase the risk of melanoma?

There is no conclusive proof that MT-II causes melanoma, but changes in nevi and hyperpigmentation have been reported that may complicate dermatological monitoring. Uncontrolled use, combined with UV exposure, may increase the overall risk of skin damage.

Why does it cause nausea and flushing?

Its non-selectivity at melanocortin receptors and its central/peripheral effects can activate neurovegetative and vascular circuits, causing symptoms such as nausea, flushing, and headache, often in a dose-dependent manner.

Is it detectable in anti-doping tests?

Peptides may be detectable using specific methods in anti-doping contexts, but detectability depends on the test, time window, and metabolites. In any case, the use of unauthorized substances may violate sporting regulations.