Peptides
Kisspeptin: The Master Regulator of Reproductive Hormones, Fertility & Testosterone (2026 Guide)
Of all the peptides in the research landscape, few are as biologically fundamental as kisspeptin. Discovered in 1996 and initially named for Hershey, Pennsylvania (home of the Hershey Kiss), kisspeptin turned out to be the master switch for human reproduction — the upstream signal that determines whether the entire hypothalamic-pituitary-gonadal (HPG)