Kisspeptin is the hormone at the top of the reproductive chain: it tells the hypothalamus to release GnRH, which tells the pituitary to release LH and FSH, which tell the testes to make testosterone and sperm. Because it works upstream, it is sold to men as a way to raise their own testosterone rather than replace it.
This page reports what has been measured in men specifically. The record in women — IVF, missing periods, low desire — has its own page on the trials in women. How kisspeptin compares with enclomiphene, the oral alternative, is on our kisspeptin vs enclomiphene page, and with hCG on our hCG vs kisspeptin page. Peptide Lexicon explains the molecule itself in its kisspeptin entry. Nothing here is a recommendation.
Two forms, one target
Two lengths of kisspeptin appear in the men's studies. Kisspeptin-54 is the full circulating form; kisspeptin-10 is the shortest fragment with full activity at the receptor. They act on the same receptor (KISS1R) but last differently: kisspeptin-54's plasma half-life in men was 27.6 minutes in the first human study, and the kisspeptin-10 studies below use either single boluses or continuous infusions lasting up to a day. A 2015 study gave both forms, and GnRH, intravenously to the same healthy men to compare them directly. The dosage page carries the doses and units.
The studies in men, by question
Every study below enrolled men and measured a hormone or behavioural outcome after kisspeptin was given. Abstracts read 26 October 2026; figures are means.
Does it raise LH and testosterone in healthy men?
| Study | Men | What was given | Result |
|---|---|---|---|
| Dhillo 2005, JCEM | 6 | Kisspeptin-54, 90-min IV infusion vs saline, crossover | LH 10.8 vs 4.2 IU/L; FSH 3.9 vs 3.2; testosterone 24.9 vs 21.7 nmol/L |
| George 2011, JCEM | 4–6 per step | Kisspeptin-10 IV boluses 0.01–3 µg/kg; infusions up to 22.5 h | Bolus peak at 1 µg/kg (LH 4.1 → 12.4 IU/L at 30 min); 3 µg/kg gave less; 22.5-h infusion: testosterone 16.6 → 24.0 nmol/L, LH pulse frequency 0.7 → 1.0/h |
| Ullah 2019, Andrologia | adult, middle-aged, older | Kisspeptin-10 1 µg/kg IV bolus | LH rose in every age group; testosterone rose only in the young adult group |
| Mills 2025, EBioMedicine | healthy men (and women) | Kisspeptin-54 nasal spray, 12.8 nmol/kg, vs placebo | LH maximal increase 4.4 IU/L above baseline in men; no adverse events reported |
The pattern is consistent: LH goes up within minutes, testosterone follows within hours. Two details are worth keeping. More was not better — in George 2011 the highest bolus produced a smaller LH response than the middle one. And age blunts the testosterone end: in Ullah 2019 the pituitary still responded in older men, but their testes did not convert the LH rise into a measurable testosterone rise.
Does it work in men with low testosterone?
George 2013 (Clinical Endocrinology) studied five men with type 2 diabetes and mildly low testosterone (mean 8.5 nmol/L, BMI about 41) against seven healthy men. A kisspeptin-10 bolus raised LH in both groups by a similar amount. An 11-hour infusion in four of the diabetic men raised testosterone from 8.5 to 11.4 nmol/L and LH pulse frequency from 0.6 to 0.9 per hour. It was a proof-of-concept study in four or five men, measured over one day.
The longer test of that idea came from industry, and it did not succeed. Takeda ran two trials of TAK-448, a synthetic kisspeptin analogue, in men:
| Trial | Who | Men enrolled | Status | Reason stopped, as registered |
|---|---|---|---|---|
| NCT02381288 | Middle-aged and older men with low testosterone | 17 | Terminated | "the study did not meet the primary endpoint" |
| NCT02369796 | Men with hypogonadotropic hypogonadism (phase 2a) | 15 | Terminated | "the study did not achieve the primary efficacy objective" |
No results are posted for either trial, so we cannot say by how much they missed. The registered reasons are the whole public record (ClinicalTrials.gov, read 26 October 2026). They are the only controlled trials of repeated kisspeptin-type dosing in men with low testosterone, and both stopped for lack of effect.
The likely reason sits in the physiology: constant kisspeptin stimulation switches the system off. A continuously infused TAK-448 drove healthy men's testosterone into the castration range within about a week — which is why the same molecule was also trialled to lower testosterone in prostate cancer. That finding, with its source, is on our peptides and testosterone page. A 2026 study tried to find a schedule that avoids it: in healthy men, continuous subcutaneous kisspeptin-10 for five days left gonadotropins no different from vehicle, while eight hours on and sixteen off sustained the LH rise over 12 days. Its design is on the dosage page.
Does it change sexual desire or erections?
One randomised trial tested this in men. Mills 2023 (JAMA Network Open) enrolled heterosexual men with hypoactive sexual desire disorder — low desire causing distress, which the authors say affects about 8% of men — in a double-blind crossover: a 75-minute kisspeptin-54 infusion on one visit and placebo on another.
- 37 men randomised, 32 completed; mean age 37.9.
- On whole-brain fMRI while watching sexual videos, kisspeptin changed activity in the sexual-processing network (Cohen's d 0.81, P = .003).
- Penile tumescence in response to the videos rose by up to 56% more than placebo (P = .02).
- On the behavioural scales, the clearest change was in "happiness about sex" (mean difference 0.63 points, P = .02).
That is a single-dose laboratory result in men with a desire disorder, not erectile dysfunction, and not repeated use. The authors' own conclusion is that kisspeptin "has potential" as a treatment; it is not one yet. The same design was also run in women with low desire; that 2022 trial in women is described separately.
Other measured effects in men
- Bone. In 26 healthy men, a 90-minute infusion raised the bone-formation marker osteocalcin by up to 20.3%, with no change in resorption markers (Comninos 2022, JCEM). A marker change over 90 minutes, not a bone-density result.
- Appetite, insulin and mood. Imperial College studies have measured brain responses to food images in healthy men, and beta-cell function and anxiety in mixed groups, under kisspeptin; the 2025 anxiety trial's title reports that reproductive hormones rose without any effect on anxiety.
What the registry shows
ClinicalTrials.gov lists 36 kisspeptin intervention studies; six enrol men only — three completed (insulin action, reproductive physiology, infertility) and three terminated: the two TAK-448 low-testosterone trials above and an early TAK-448 prostate-cancer study stopped to develop a new formulation (registry API, read 26 October 2026). Sixteen enrol only women and fourteen enrol both.
Kisspeptin in sport
A 2026 doping-control paper from the Cologne laboratory (Krombholz 2026, Drug Testing and Analysis) states that kisspeptin-54, its shorter forms and synthetic agonists such as TAK-448 were added to WADA's Prohibited List in 2024 as testosterone-stimulating peptides prohibited for male athletes, and describes a mass-spectrometry method for detecting them. Native kisspeptins proved unstable in blood and urine, so the authors propose testing for their breakdown products.
Side effects in men
The men's studies report few adverse events, but they gave single doses or short infusions to small groups under supervision. Across kisspeptin trials of both sexes, the logged effects and the evidence that daily use shuts the axis down are collected on our kisspeptin side effects page.
What is not established
- A sustained testosterone rise from repeated kisspeptin in men with low testosterone — the two controlled trials that tested an analogue were terminated for missing their endpoints.
- Effects on sperm production or fertility in men from any repeated schedule.
- Treatment of erectile dysfunction — the one sexual-function trial studied low desire, with one dose.
- Use in men on, or coming off, testosterone or anabolic steroids — not studied.
- Any product other than study-grade peptide given under hospital supervision.
Low testosterone has many causes, and the right test of whether the pituitary can respond is a clinical one. Any decision about hormone treatment belongs with an endocrinologist or urologist.
Sources and dates
- Dhillo WS et al. Kisspeptin-54 stimulates the hypothalamic-pituitary gonadal axis in human males. J Clin Endocrinol Metab. 2005;90(12):6609–15. PMID 16174713.
- George JT et al. Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men. J Clin Endocrinol Metab. 2011;96(8):E1228–36. PMID 21632807.
- George JT et al. Kisspeptin-10 stimulates serum testosterone and LH secretion in men with type 2 diabetes and mild biochemical hypogonadism. Clin Endocrinol. 2013;79(1):100–4. PMID 23153270.
- Ullah H et al. Age-dependent changes in the reproductive axis responsiveness to kisspeptin-10 administration in healthy men. Andrologia. 2019;51(4):e13219. PMID 30590872.
- Mills EG et al. Effects of kisspeptin on sexual brain processing and penile tumescence in men with hypoactive sexual desire disorder. JAMA Netw Open. 2023;6(2):e2254313. PMID 36735255; ISRCTN17271094.
- Mills EG et al. Intranasal kisspeptin administration rapidly stimulates gonadotropin release in humans. EBioMedicine. 2025;115:105689. PMID 40215751.
- Comninos AN et al. Acute effects of kisspeptin administration on bone metabolism in healthy men. J Clin Endocrinol Metab. 2022;107(6):1529–40. PMID 35244717.
- Krombholz S et al. Analysis and characterization of kisspeptin and its analogues in serum and urine samples by LC-HRMS for doping control purposes. Drug Test Anal. 2026;18(7):862–76. PMID 42057309.
- Yeung AC et al. Chronic subcutaneous kisspeptin-10 stimulates gonadotropin secretion for 12 days in healthy men. Eur J Endocrinol. 2026. PMID 42549827 — as documented on our kisspeptin dosage page.
- ClinicalTrials.gov API v2: intervention "kisspeptin" (36 studies; six male-only); NCT02381288, NCT02369796 and NCT01132404 records incl. reasons for termination — read 26 October 2026. PubMed census of human kisspeptin administration studies in men (43 records) — 26 October 2026.