Tanning & Sexual Health

PT-141 (Bremelanotide) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (α-MSH) developed as a melanocortin receptor agonist. Originally derived from Melanotan II in the 1990s by Palatin Technologies, bremelanotide was specifically developed to address sexual dysfunction after the parent compound unexpectedly caused sexual arousal in clinical trials for tanning. The peptide primarily activates melanocortin receptors MC3R and MC4R in the central nervous system, particularly in the hypothalamic regions involved in sexual response. After extensive clinical development including two large Phase 3 RECONNECT trials involving over 1,200 premenopausal women, bremelanotide received FDA approval in June 2019 for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. It is marketed as Vyleesi and administered as a 1.75 mg subcutaneous injection at least 45 minutes before anticipated sexual activity. The FDA considers it a first-in-class medication, representing a novel non-hormonal approach to treating sexual dysfunction through central melanocortin pathway activation.

Melanotan 2 (MT-2) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (α-MSH) with the molecular formula C50H69N15O9 and CAS number 121062-08-6. It functions as a non-selective agonist of melanocortin receptors MC1, MC3, MC4, and MC5, demonstrating up to 1000 times greater potency than endogenous α-MSH. Originally developed for photoprotection through melanogenesis, clinical research has primarily focused on its effects on sexual function, with multiple double-blind placebo-controlled trials demonstrating significant erectogenic properties in men with both psychogenic and organic erectile dysfunction. Additional research areas include metabolic effects, neuroprotection, and appetite suppression. Despite showing clinical efficacy in phase I trials, Melanotan 2 has never received regulatory approval from the FDA, EMA, TGA, or other major health authorities. It remains widely available through unregulated online markets as an unapproved cosmetic tanning agent and sexual enhancement compound, with significant safety concerns including associations with melanoma development, dysplastic nevi, nausea, cardiovascular effects, and unknown long-term risks due to lack of comprehensive safety studies.

Melanotan I (Afamelanotide) is a synthetic peptide analogue of α-melanocyte-stimulating hormone (α-MSH). It is FDA-approved under the brand name Scenesse for the treatment of erythropoietic protoporphyria (EPP), a rare genetic disorder causing severe photosensitivity. Unlike Melanotan II, Melanotan I is a linear peptide and has a different mechanism and safety profile.

Alpha-melanocyte-stimulating hormone (α-MSH) is a 13-amino acid neuropeptide derived from proopiomelanocortin (POMC) that acts as a potent regulator of melanogenesis, immune function, and metabolic homeostasis. By binding to melanocortin receptors (primarily MC1R in melanocytes), α-MSH stimulates eumelanin synthesis, enhances DNA repair mechanisms, and provides photoprotection against UV-induced damage. Beyond pigmentation, α-MSH exhibits powerful anti-inflammatory properties by modulating cytokine production and immune cell function, regulates appetite and energy expenditure through central melanocortin pathways, and influences sexual arousal and erectile function via MC3R and MC4R activation in the hypothalamus.