Category · Melanocortins
Melanocortins: approved to gray-market.
Peptides that act on the melanocortin receptor family — touching skin pigmentation, libido, energy balance, and appetite. Spans FDA-approved drugs (afamelanotide, setmelanotide), an approved sexual-dysfunction agent (PT-141), and the gray-market "tan in a bottle" (melanotan-2).
Five receptors, very different effects. MC1R is the pigmentation target (afamelanotide, melanotan-2). MC3R and MC4R sit at the center of energy balance and appetite (setmelanotide is FDA-approved for rare obesity caused by MC4R-pathway defects). And MC4R agonism in the hypothalamus drives the sexual-function effect that gets PT-141 (bremelanotide) approved for hypoactive sexual desire disorder.
Important: melanotan-2 is the gray-market cousin, not an approved drug. It binds the same receptors, but the safety, purity, and clinical evidence are nowhere near the approved counterparts.
- 10/10 · Established PT-141 Low sexual desire and arousal — HSDD in women; also studied in erectile dysfunction.
- 10/10 · Established Setmelanotide Rare melanocortin-pathway obesity: POMC/PCSK1 deficiency, LEPR deficiency, Bardet-Biedl syndrome, and acquired hypothalamic obesity.
- 9/10 · Strong Afamelanotide Preventing phototoxicity in adults with erythropoietic protoporphyria (EPP)
- 6/10 · Preliminary Melanotan II Skin tanning (melanogenesis); sexual arousal and erectile function in early research.
Reading this class honestly
The receptor family is real and well-characterized; the gap between approved drugs (where you can trust the dose, purity, and indication) and gray-market peptides binding the same receptors is large. See how we grade and the gray market for context.