Libido & sexual function

Synthetic cyclic heptapeptide acting as a non-selective melanocortin-receptor agonist. FDA-approved in 2019 as Vyleesi for hypoactive sexual desire disorder (HSDD) in pre-menopausal women.

Gonadorelin is the synthetic decapeptide with an amino-acid sequence identical to endogenous gonadotropin-releasing hormone (GnRH/LHRH). Historically approved in several countries for diagnostic testing of pituitary function and for fertility indications (pump systems). A defining feature is the opposite effect of pulsatile versus continuous administration: pulsatile stimulates, continuous leads to receptor desensitisation.

Kisspeptin-10 is the shortest bioactive fragment (10 amino acids) of the endogenous neuropeptide kisspeptin, encoded by the KISS1 gene. It acts as an agonist at the KISS1R (GPR54) receptor and stimulates hypothalamic GnRH neurons, driving release of LH and FSH. Kisspeptin is a master switch of puberty and reproduction and is studied in humans, notably by the group of Waljit Dhillo (Imperial College London), in reproductive disorders and in sexual and emotional brain processing. It is not an approved drug.

Oxytocin is an endogenous nonapeptide hormone of the posterior pituitary. In synthetic form (Pitocin, Syntocinon) it has been approved for decades to induce and augment labour and to control postpartum uterine bleeding. Strictly separate from this is intranasal use to influence social behaviour, trust, anxiety or autism symptoms: this use is unapproved, purely experimental, and yields inconsistent and often negative results in controlled trials.