Kisspeptin-10 vs Kisspeptin-54

Kisspeptin-10 is the shortest kisspeptin sequence that retains full activity at the kisspeptin receptor ¹. In healthy men, intravenous boluses produced a rapid, dose-related rise in serum LH, and continuous infusion raised LH pulse frequency, pulse size and testosterone ¹.

A 2026 randomised, single-blinded, placebo-controlled study in 15 healthy men examined longer administration: continuous subcutaneous infusion over 5 days left gonadotropins similar to vehicle while testosterone stayed raised, whereas daily intermittent 8-hour infusions over 12 days sustained gonadotropin increases, and a later bolus still produced a response, indicating the receptor remained functional ³. Registered kisspeptin-10 studies are small and single-centre ¹⁰, and the FDA lists kisspeptin-10 in 503A category 2 ^11,13.

Kisspeptin-54 is described as the major circulating kisspeptin isoform in humans, with a measured plasma half-life of about 28 minutes in male volunteers ². In 6 men, infusion raised LH, FSH and testosterone versus saline ². In women, a subcutaneous bolus raised LH in all phases of the menstrual cycle, with the largest rise in the preovulatory phase ⁴.

It has gone further clinically. In 53 women undergoing IVF, a single injection induced egg maturation, with fertilisation and embryo transfer in 92% and clinical pregnancy in 23% ⁸. In a phase 2 open-label randomised trial in 60 women at high risk of ovarian hyperstimulation syndrome, egg maturation occurred in 95%, live birth per transfer was 45%, and no woman developed moderate, severe or critical ovarian hyperstimulation syndrome ⁶. Repeated twice-daily injection over 2 weeks in women with hypothalamic amenorrhoea produced a markedly reduced hormone response by day 14, described by the authors as desensitisation ⁵. A 2025 randomised crossover study reported that intranasal kisspeptin-54 raised LH in healthy men and women and in patients with hypothalamic amenorrhoea ⁷.