Kisspeptin-10 Research

Kisspeptin-10 is a synthetic decapeptide used in research on reproductive hormone control. ^[1] It is the shortest fragment of the human KISS1 gene product that retains full activity at the kisspeptin receptor. ^[1] Human kisspeptin-10 research consists almost entirely of small physiological studies measuring luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone and other reproductive steroids. ^[3][10][14] A much larger literature uses kisspeptin-54, a different molecule, and the two must be kept apart. ^[4][5][6]

What kisspeptin-10 is

Kisspeptin-10 corresponds to residues 112 to 121 of the KISS1 precursor, also written as metastin 45-54, and its sequence is Tyr-Asn-Trp-Asn-Ser-Phe-Gly-Leu-Arg-Phe with a C-terminal amide. ^[1] PubChem records the free base as C63H83N17O14, molecular weight 1302.4, CAS 374675-21-5. ^[1] Research-grade Kisspeptin-10 is usually supplied as an acetate or trifluoroacetate salt, which does not conflict with that CAS. ^[1]

Kisspeptin-54 shares the same C-terminal ten residues but is a 54-residue peptide of far greater mass. ^[7] Almost every headline human kisspeptin study used kisspeptin-54, including the brain-imaging and sexual-desire trials, so those results are not kisspeptin-10 data. ^[4][5][6] Kisspeptin-13 and kisspeptin-14 extend the same C-terminus, so residue count needs checking before a paper counts as kisspeptin-10 evidence. ^[26] Much preclinical work uses the rodent kisspeptin-10 sequence, which ends in tyrosine where the human decapeptide ends in phenylalanine. ^[26]

Mechanism of action

Kisspeptin-10 is an agonist at the kisspeptin receptor, also called KISS1R or GPR54. ^[7] In healthy men, a single intravenous bolus produced an immediate LH pulse and delayed the next endogenous pulse. ^[2] That points to an action upstream at the GnRH pulse generator rather than at the pituitary. ^[2] In juvenile rhesus monkeys under continuous exposure, a further kisspeptin bolus no longer evoked LH. ^[8] GnRH and NMDA boluses still did, placing the desensitization at the receptor with the downstream machinery intact. ^[8] In adult monkeys the same kind of infusion truncated the bolus response at the lower dose and abolished it at the higher one. ^[23] There the pituitary response to a GnRH bolus was itself compromised, so the downstream machinery was not intact in adults. ^[23]

In mice, systemically injected kisspeptin-54, but not kisspeptin-10, activated c-FOS in GnRH neurons behind the blood-brain barrier. ^[7] Repeated kisspeptin-10 injections given to offset its shorter half-life did not reproduce the sustained LH rise seen after kisspeptin-54, so clearance alone does not explain the gap. ^[7] The authors attribute it to barrier penetration and pharmacokinetics together. ^[7] Those half-lives, roughly 32 minutes for kisspeptin-54 and roughly 4 minutes for kisspeptin-10, were measured in mice, not in people. ^[7] The same authors caution that they gave human peptides to mice, and do not know whether murine kisspeptins behave differently. ^[7] Human plasma half-life has been reported separately for kisspeptin-54 at 27.6 minutes. ^[9]

Human research on kisspeptin-10

The foundational human study gave intravenous boluses to healthy men and saw a rapid, dose-related LH rise. ^[3] At its top dose that same study saw an inversion, with the higher bolus producing a significantly smaller LH response than the lower one. ^[3] Continued infusion in those men raised LH, testosterone and LH pulse frequency. ^[3]

A single-blinded human crossover study compared the two isoforms in healthy men. ^[10] At the doses tested, continuous intravenous kisspeptin-10 and kisspeptin-54 were associated with similar gonadotropin responses, and GnRH was more potent than either. ^[10] The authors flagged the small sample size themselves. ^[10] Those authors also state that kisspeptin-54 but not kisspeptin-10 can be given subcutaneously, because of its longer half-life. ^[10]

Five days of continuous subcutaneous kisspeptin-10 in healthy men left gonadotropins similar to vehicle, while testosterone remained elevated. ^[11] That continuous arm enrolled four men. ^[11] Intermittent exposure over twelve days sustained the gonadotropin rise, and the receptor still responded to a bolus afterwards. ^[11] That study delivered kisspeptin-10 subcutaneously, so the route judgement is not settled. ^[10][11] The second human study infused kisspeptin-10 continuously for 24 hours in three men, and LH rose five- to eight-fold before declining 13 to 47 percent from its peak. ^[12] LH was still several-fold above baseline at the end of that human infusion. ^[12] With three participants those point estimates are not established parameters. ^[12] That is a decline from peak rather than the loss of response reported in monkeys. ^[8][12][23]

In men with type 2 diabetes and low testosterone, a small human proof-of-concept study found kisspeptin-10 raised LH and testosterone. ^[13] In women with cabergoline-resistant hyperprolactinemic amenorrhea, infused kisspeptin-10 raised LH, FSH and ovarian steroids. ^[14] That human report enrolled two patients and its authors called it exploratory. ^[14]

Evidence in women is inconsistent

One human study found no gonadotropin change in follicular-phase women by any route tested, with the response returning in the preovulatory phase. ^[15] A second human study, from an independent group, found significant LH stimulation in early-follicular women. ^[16] A third human study found unambiguous responses in only half of its early-follicular participants, and raising the dose did not improve them. ^[17]

The human female response is modulated by sex-steroid background, with responses largest in post-menopausal women and not significant in women taking a combined oral contraceptive. ^[16] The same human study that examined cycle phase did not find pulse-generator resetting in women. ^[17] That is a documented failure to extend, by the group that first described the finding in men. ^[2][17]

What the human evidence does not show

No human kisspeptin-10 data on sexual desire, arousal or erectile function were identified, because the trials reporting those outcomes used kisspeptin-54. ^[4][5][6] In a human study of congenital idiopathic hypogonadotropic hypogonadism, every patient with persisting disease failed to respond. ^[18] The authors read that as the GnRH network needing to be functional for kisspeptin to act. ^[18]

TAK-448, also called MVT-602, is sometimes borrowed as evidence, but PubChem records a distinct nonapeptide with its own CAS number and formula. ^[24] Its human Phase 1 record showed testosterone falling to below-castration concentrations under sustained exposure. ^[19] Two Phase 2 studies of it in male hypogonadism were terminated for missing their primary endpoints. ^[20] Neither result is kisspeptin-10 evidence, and neither should be omitted on that ground. ^[19][20]

Two registered kisspeptin-10 trials of insulin secretion were withdrawn before enrolling anyone, one for futility and one because the planned enrollment was judged insufficiently powered. ^[25]

No human kisspeptin-10 study identified has used a clinical endpoint. ^[3][10][11] Across the published human record the outcomes are biochemical, chiefly LH, FSH, testosterone and other reproductive steroids, over hours to days. ^{[3][10][11][14]} The largest human kisspeptin-10 administration study identified enrolled fifteen participants. ^[11]

A preclinical safety signal

Repeated intraperitoneal kisspeptin-10 in prepubertal male rats significantly reduced plasma testosterone and produced ultrastructural degeneration of Leydig cells. ^[21] Three dose levels were given, and the testosterone reduction reached significance at the two higher ones and not at the lowest. ^[21] That animal study was small and used prepubertal rats by a non-clinical route. ^[21]

Regulatory status

Kisspeptin-10 is not an approved medicine in any jurisdiction identified. ^[22] FDA lists it as an active Category 2 bulk drug substance for compounding, dated September 2023. ^[22] The listed grounds are immunogenicity risk, impurity and characterization complexity, and limited safety information. ^[22] Several US National Drug Code entries list it as a bulk ingredient from suppliers, which is an administrative listing rather than a review or approval. ^[22]

Conflicts of interest within the literature

Two authors of the 2026 chronic-exposure human study declare consultancy for the company developing a kisspeptin-receptor analogue. ^[11] The senior author of the 24-hour infusion study declares a financial interest in a reproductive-treatment company. ^[12] The TAK-448 Phase 1 report is authored largely by sponsor employees, and its finding runs against the sponsor's own commercial thesis. ^[19]

Group concentration differs by isoform: human kisspeptin-10 studies come from at least four independent groups on three continents. ^{[2][3][15][27]} The kisspeptin-54 literature is close to a single group's program, and that is the literature a kisspeptin-10 page is most tempted to borrow. ^[4][5][6]

Limitations and current directions

Kisspeptin-10 is best described as a well-characterized physiological probe rather than a candidate treatment. ^[3][10][11] The gonadotropin result depends on the exposure pattern, since continuous and intermittent regimens differed in the same human study. ^[11] Testosterone stayed elevated under both schedules, so that study showed no reversal of direction. ^[11] Current human work remains physiological, using kisspeptin-10 to interrogate GnRH pulse generation. ^[12]

Conclusion

Kisspeptin-10 has a genuine, independently produced human record of small physiological studies of gonadotropin, testosterone and other reproductive steroid release. ^[3][10][11] Within that record no clinical-outcome trial and no human sexual-function data were identified. ^{[4][5][6][11]} Two common errors are importing kisspeptin-54 results and generalizing male findings to women. ^{[4][5][6][15]} Kisspeptin-10 remains a research compound with no approved use in any jurisdiction identified. ^[22]

References

1. 1

   PubChem Compound Summary CID 25240297, Kisspeptin-10 (human). National Center for Biotechnology Information. CAS 374675-21-5, C63H83N17O14, MW 1302.4. Database record, not a peer-reviewed source.
2. 2

   Chan YM, et al. Kisspeptin resets the hypothalamic GnRH clock in men. J Clin Endocrinol Metab. 2011;96(6):E908-15. PMID 21470997.
3. 3

   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.
4. 4

   Comninos AN, et al. Kisspeptin modulates sexual and emotional brain processing in humans. J Clin Invest. 2017;127(2):709-719. PMID 28112678.
5. 5

   Thurston L, et al. Effects of kisspeptin administration in women with hypoactive sexual desire disorder: a randomized clinical trial. JAMA Netw Open. 2022;5(10):e2236131. PMID 36287566.
6. 6

   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.
7. 7

   d'Anglemont de Tassigny X, et al. Mechanistic insights into the more potent effect of KP-54 compared to KP-10 in vivo. PLoS One. 2017;12(5):e0176821. PMID 28464043. Erratum: PLoS One. 2018;13(1):e0192014. PMID 29370263.
8. 8

   Seminara SB, et al. Continuous human metastin 45-54 infusion desensitizes G protein-coupled receptor 54-induced gonadotropin-releasing hormone release monitored indirectly in the juvenile male Rhesus monkey (Macaca mulatta): a finding with therapeutic implications. Endocrinology. 2006;147(5):2122-6. PMID 16469799.
9. 9

   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.
10. 10

    Jayasena CN, et al. Direct comparison of the effects of intravenous kisspeptin-10, kisspeptin-54 and GnRH on gonadotrophin secretion in healthy men. Hum Reprod. 2015;30(8):1934-41. PMID 26089302.
11. 11

    Yeung AC, et al. Chronic subcutaneous kisspeptin-10 stimulates gonadotropin secretion for 12 days in healthy men. Eur J Endocrinol. 2026;195(2):206-216. PMID 42549827.
12. 12

    Naveed A, et al. Dynamic modulation of LH secretion by continuous kisspeptin infusion in healthy men. Hormones (Athens). 2026, online ahead of print. DOI: 10.1007/s42000-026-00795-y. PMID 42230485.
13. 13

    George JT, et al. Exploring the pathophysiology of hypogonadism in men with type 2 diabetes: kisspeptin-10 stimulates serum testosterone and LH secretion in men with type 2 diabetes and mild biochemical hypogonadism. Clin Endocrinol (Oxf). 2013;79(1):100-4. PMID 23153270.
14. 14

    Millar RP, et al. Hypothalamic-pituitary-ovarian axis reactivation by kisspeptin-10 in hyperprolactinemic women with chronic amenorrhea. J Endocr Soc. 2017;1(11):1362-1371. PMID 29264460.
15. 15

    Jayasena CN, et al. The effects of kisspeptin-10 on reproductive hormone release show sexual dimorphism in humans. J Clin Endocrinol Metab. 2011;96(12):E1963-72. PMID 21976724.
16. 16

    George JT, et al. Kisspeptin-10 stimulation of gonadotrophin secretion in women is modulated by sex steroid feedback. Hum Reprod. 2012;27(12):3552-9. PMID 22956346.
17. 17

    Chan YM, et al. Kisspeptin administration to women: a window into endogenous kisspeptin secretion and GnRH responsiveness across the menstrual cycle. J Clin Endocrinol Metab. 2012;97(8):E1458-67. PMID 22577171.
18. 18

    Chan YM, et al. Exogenous kisspeptin administration as a probe of GnRH neuronal function in patients with idiopathic hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 2014;99(12):E2762-71. PMID 25226293.
19. 19

    MacLean DB, et al. Sustained exposure to the investigational Kisspeptin analog, TAK-448, down-regulates testosterone into the castration range in healthy males and in patients with prostate cancer: results from two phase 1 studies. J Clin Endocrinol Metab. 2014;99(8):E1445-53. PMID 24762108.
20. 20

    ClinicalTrials.gov records NCT02369796 and NCT02381288 (TAK-448, both TERMINATED, sponsor-stated failure to meet the primary objective/endpoint). Trial registry, not a peer-reviewed source.
21. 21

    Ramzan F, et al. Dose-dependent degeneration of Leydig cells following kisspeptin-10 administration: an ultrastructural study. Protein Pept Lett. 2022;29(1):64-70. PMID 34961438.
22. 22

    US Food and Drug Administration. Certain bulk drug substances for use in compounding that may present significant safety risks (Category 2, 503A; Kisspeptin-10 listed 29 September 2023), and the openFDA National Drug Code directory. Regulatory records, not peer-reviewed sources.
23. 23

    Ramaswamy S, et al. Effect of continuous intravenous administration of human metastin 45-54 on the neuroendocrine activity of the hypothalamic-pituitary-testicular axis in the adult male rhesus monkey (Macaca mulatta). Endocrinology. 2007;148(7):3364-70. PMID 17412800.
24. 24

    PubChem Compound Summary CID 46700761, TAK-448. National Center for Biotechnology Information. CAS 1234319-68-6, C58H80N16O14, MW 1225.4; synonyms include MVT-602 and RVT-602. Database record, not a peer-reviewed source.
25. 25

    ClinicalTrials.gov records NCT05456854 and NCT04532801 (kisspeptin-10 insulin-secretion studies, both WITHDRAWN; reasons stated as "Futility" and as interim data showing planned enrollment insufficiently powered). Trial registry, not a peer-reviewed source.
26. 26

    UniProt Knowledgebase, reviewed KISS1 precursor entries Q15726 (human), Q6Y4S4 (mouse) and Q7TSB7 (rat). Annotated kisspeptin-10 peptide features: human residues 112-121, YNWNSFGLRF, C-terminal phenylalanine amide; mouse and rat residues 110-119, YNWNSFGLRY, C-terminal tyrosine amide. Human kisspeptin-13 (109-121) and kisspeptin-14 (108-121) are annotated on the same C-terminus. Database records, not peer-reviewed sources.
27. 27

    Ullah H, Nabi G, Zubair H, Ullah R, Shahab M. Age-dependent changes in the reproductive axis responsiveness to kisspeptin-10 administration in healthy men. Andrologia. 2019;51(4):e13219. PMID 30590872.