Kisspeptin-10: the signal upstream of GnRH and what human studies report

Kisspeptin-10 is a 10-amino-acid peptide from the kisspeptin family, the signals that sit upstream of gonadotropin-releasing hormone (GnRH) in the reproductive axis. It is cut from the same KISS1 precursor as longer forms such as kisspeptin-13 and kisspeptin-54, and it is the form used in several of the human studies below. This note summarizes what those studies measured.

Where it acts

Most human work measures LH in blood after kisspeptin is given, because LH is a practical stand-in for GnRH release, which cannot be sampled directly in people. A 2013 review by Chan summarizes how the isoform, the route and the pattern of exposure change the LH response.

How the pattern of exposure changes the answer

The review reports several findings from the early human studies. A brief exposure to kisspeptin produces sustained GnRH release lasting about 17 minutes in men. Women respond differently across the menstrual cycle, which suggests that natural kisspeptin signaling and GnRH neuron responsiveness change with the sex-steroid environment. Kisspeptin resets the GnRH pulse generator in men but does not appear to do so in women.

The result that matters most for study design is desensitization. Continuous exposure to kisspeptin blunts the response, so the same molecule can stimulate or suppress reproductive hormone activity depending on how exposure is patterned.

Twelve days in healthy men

A 2026 paper in the European Journal of Endocrinology tested three patterns of subcutaneous kisspeptin-10 in healthy men. The acute infusions raised LH, FSH and testosterone compared with vehicle (P < .0001). Five days of continuous infusion left testosterone elevated, but gonadotropin concentrations were similar to vehicle, which fits the desensitization described above.

Daily 8-hour infusions over 12 days kept gonadotropins up. The mean LH increase was -0.16 ± 0.19 with vehicle, +1.68 ± 0.25 on day 1 and +1.14 ± 0.33 on day 12 (P = .003 versus vehicle). A bolus after the 12 days still raised gonadotropins, so the receptor was still working. The authors present the work as groundwork for studies in reproductive disorders.

Age and route

A 2019 study in Andrologia gave a single intravenous bolus of kisspeptin-10 to healthy men in three age groups. LH rose significantly in all of them, but testosterone rose significantly only in the youngest group. The authors read that as a pituitary axis that stays responsive across life, with Leydig cell responsiveness to LH declining with age.

A 2025 paper in EBioMedicine tested intranasal kisspeptin-54 in a randomized, double-blind, crossover, placebo-controlled study. It raised LH in healthy men, healthy women and women with hypothalamic amenorrhoea, with no side effects or adverse events reported. The nasal spray was stable for up to 60 days at 4 °C. Mouse experiments pointed to GnRH neurons in the olfactory system as a possible route for the effect.

Reading these results

Four points limit how far the findings reach.

• LH is a surrogate. These papers measure hormone levels, not fertility or any health outcome.
• Isoform and route matter. Kisspeptin-10 and kisspeptin-54, and subcutaneous, intravenous and intranasal delivery, gave different response profiles, so results do not transfer between them.
• Exposure pattern matters. Continuous exposure desensitized the response, while the intermittent pattern did not in the 12-day study.
• The studies are small. The 2026 paper had 15 men spread over three sub-studies.

Kisspeptin-10 is a short peptide with a calculated average mass of about 1,302 Da. A certificate of analysis for it should show an observed mass close to that figure.