MT-2 · Melanocortin Receptor Agonist · Tanning Peptide
A synthetic analogue of alpha-melanocyte stimulating hormone (α-MSH) that activates melanocortin receptors to stimulate melanogenesis (skin darkening), increase libido and suppress appetite. One of the most widely used peptides globally despite being unapproved — with a significant safety and regulatory profile that users must understand.
Melanotan II is a synthetic cyclic analogue of alpha-melanocyte stimulating hormone (α-MSH), a naturally occurring peptide that regulates skin pigmentation, sexual function and appetite. It was originally developed at the University of Arizona in the 1980s as a potential tanning agent to reduce UV-dependent skin cancer risk. Despite never completing clinical trials or receiving regulatory approval, it became one of the most widely used research peptides globally.
Melanotan II is a non-selective melanocortin receptor agonist — it activates MC1R (melanogenesis, skin darkening), MC3R (energy homeostasis, appetite regulation) and MC4R (sexual function, arousal, appetite). The simultaneous activation of all three receptor types produces its characteristic combined effects: skin darkening without UV exposure, increased sexual desire and function, and appetite suppression with potential weight loss benefits.
Melanotan II was upgraded to Schedule 9 (Prohibited Substance) in Australia in February 2026 — the most restrictive scheduling category, equivalent to heroin and methamphetamine in terms of supply restrictions. This means supply, possession for supply and importation carry serious criminal penalties in Australia. This regulatory context is critical for Australian users to understand before considering this compound.
Beyond the regulatory concerns, Melanotan II carries specific safety considerations. It activates existing melanocytic naevi (moles) — there are documented cases of moles changing colour, size or characteristics during use, which can complicate skin cancer surveillance. Blood pressure elevation, nausea, facial flushing and spontaneous erections are common side effects. The long-term effects of chronic melanocortin receptor stimulation are unknown as no long-term human safety studies exist.