Melanotan II: Complete Guide

Melanotan II was developed in the 1990s by researchers at the University of Arizona who were investigating ways to stimulate the body's natural tanning response without UV radiation exposure. The goal was photoprotection — creating a "biological sunscreen" that would reduce skin cancer risk by darkening skin through melanin production.

The peptide activates multiple melanocortin receptor subtypes, which explains its diverse effects: MC1R activation causes melanin production (tanning), MC4R activation affects sexual function and appetite, and MC3R activation influences energy balance.

Melanotan II has never received regulatory approval anywhere in the world. Health authorities in the US, EU, UK, and Australia have issued warnings about its use due to safety concerns including potential effects on existing moles and the risk of masking melanoma development.

Melanotan II is a non-selective melanocortin agonist:

• MC1R (skin): Stimulates melanocytes to produce eumelanin (dark pigment), resulting in skin darkening independent of UV exposure
• MC4R (brain): Activates hypothalamic pathways involved in sexual desire, appetite regulation, and energy balance
• MC3R (metabolic): Influences energy homeostasis and fat metabolism

The tanning effect is cumulative — repeated doses produce progressive darkening over days to weeks. The effect persists for weeks after discontinuation before gradually fading.

Melanotan II is typically used at 0.25–0.5 mg per day via subcutaneous injection during an initial "loading" phase, then reduced to 0.25–0.5 mg once or twice weekly for maintenance. Some protocols include brief UV exposure (10-20 minutes) within hours of dosing to enhance melanin activation.

Use the peptide calculator for reconstitution volumes.

Melanotan II carries significant safety concerns:

• Nausea (very common): Often severe with initial doses
• Facial flushing
• Mole changes: Can darken existing moles and make melanoma detection more difficult — a serious dermatological concern
• Blood pressure changes: Transient increases
• Spontaneous erections (in males)
• Appetite suppression
• Injection site reactions
• Unknown long-term cancer risk: While designed to be photoprotective, the effect on existing melanocytic lesions raises concern about melanoma risk

Health authorities in the US, UK, EU, and Australia have issued public warnings about melanotan II use. The peptide is not approved for human use and its long-term safety profile is unknown.