Sexual Health & Tanning Peptides

Sexual health and tanning peptides target the melanocortin system — a network of receptors (MC1R through MC5R) distributed throughout the brain and peripheral tissues that govern an extraordinary range of physiological functions including skin pigmentation, sexual arousal, appetite, inflammation, and cardiovascular tone. Most peptides in this category are analogues of alpha-melanocyte-stimulating hormone (alpha-MSH).

PT-141 (bremelanotide) is the only peptide in this category to have achieved pharmaceutical approval. Approved by the US FDA as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women, PT-141 activates MC4R in the hypothalamus to generate sexual arousal through a central (brain-based) mechanism rather than the peripheral vascular mechanism of PDE5 inhibitors like sildenafil. This makes it potentially effective in cases where erectile dysfunction or HSDD has a predominantly neurological rather than vascular basis. PT-141 is also researched for sexual dysfunction in men.

Melanotan II (MT-II) is a non-selective melanocortin agonist — it activates MC1R (tanning, skin pigmentation), MC4R (sexual arousal), and other receptor subtypes simultaneously. This broad activation produces the combination of accelerated skin tanning and sexual arousal for which it became widely (though illegally) used in the late 2000s. The non-selectivity of MT-II is precisely its liability: activation of MC3R and MC5R produces nausea, flushing, and spontaneous erections; and the strong MC1R activation raises concerns about atypical mole growth and potential melanoma risk.

Afamelanotide (Scenesse, Clinuvel) is an alpha-MSH analogue that achieved European and US approval for erythropoietic protoporphyria — a rare light-sensitivity disorder. It demonstrates that selective MC1R targeting can be achieved therapeutically and validates the melanocortin system as a pharmaceutical target.

In the UK, PT-141 is not licensed by the MHRA but can be compounded and prescribed on a named-patient basis. Melanotan II is a Class C analogue under the Misuse of Drugs Act in some interpretations, though legal status is complex. The MHRA has repeatedly warned against unsupervised use of tanning peptides due to serious adverse events including melanoma activation.