Melanotan II (also known as MT-II or MT-2) is an injectable peptide hormone used to promote tanning. MT-II works by stimulating alpha-melanocyte receptors, which promotes formation of melanin in response to sun exposure. When a substantial amount of MT-II has been taken within recent “memory” of the skin cells, an individual tans as if he were a genetically darker type.

Melanotan II is an effective injectable peptide product to enhance ability to tan. Dosing is typically 0.5 to 1.0 mg/day, and the total amount needed for good effect is typically 30-40 mg, though for individuals of medium darkness already, it may be as low as 10 mg for significant effect. MT-II can also be used to enhance tendency to penile erection, but frequency of such use needs to be limited to avoid excessive total effect on skin pigmentation.