Melanotan II
Melanotan II is a synthetic cyclic analogue of alpha-MSH that stimulates melanin production (tanning) and can trigger erections; the melanocortin research on sexual function later led to the separately approved drug bremelanotide (PT-141). Melanotan II itself has only limited early human study data, is not approved by any regulator, and is widely sold through unregulated channels despite official safety warnings.
Mechanism
In plain terms, melanotan II switches on the pigment-producing pathway in the skin (causing tanning) and also acts on brain pathways linked to sexual arousal and appetite. Technically, it is a non-selective agonist of melanocortin receptors, including MC1R (which drives melanogenesis) and central MC4R/MC3R; MC1R activation on melanocytes stimulates eumelanin synthesis, while central melanocortin signalling underlies effects on sexual function and appetite. Reported adverse effects include nausea, flushing, blood-pressure changes, and darkening or change in appearance of moles, and regulators have flagged additional risks from unlicensed, non-sterile products.
Regulatory Status by Region
- United States (FDA)Not approved for any use; the FDA treats melanotan II as an unapproved new drug that is marketed illegally, including as an injectable tanning product.
- Australia (TGA)Not on the Australian Register of Therapeutic Goods (ARTG); melanotan I and II are unapproved substances, and the TGA has warned consumers against unapproved injectable tanning products. Supply for therapeutic use falls in the prescription-only class.
- European Union (EMA)No EU marketing authorisation. Melanotan II is an unlicensed product; European medicines regulators, including the UK's MHRA, have issued public safety warnings, and its sale is illegal in the UK.
- WADANot specifically named on the WADA Prohibited List; melanocortin receptor agonists are not a listed prohibited class. As an unapproved substance, athletes should nonetheless verify its current status.
Key Studies
- Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide, in a pilot phase I clinical study (Dorr RT, et al. Life Sci. 1996.)
- Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study (Wessells H, et al. J Urol. 1998.)