Kisspeptin-10
KP-10, metastin 45-54, kisspeptin-112-121, KISS1(112-121), kisspeptin decapeptide
Kisspeptin-10 is the shortest fully active fragment of kisspeptin, the hypothalamic peptide that sits immediately upstream of GnRH and acts as the master switch for the human reproductive axis. Its genuine human evidence is narrow: intravenous infusion raises LH pulse frequency and testosterone in men. The randomised trials in low sexual desire that are routinely cited for it used a different molecule - kisspeptin-54 - and no trial of any kisspeptin has tested the self-injected product sold online.
Mechanism
Kisspeptin-10 is the C-terminal decapeptide of kisspeptin, the product of the KISS1 gene, and the endogenous ligand for KISS1R (formerly GPR54), a Gq/11-coupled G-protein-coupled receptor. Kisspeptin neurons in the arcuate nucleus and the anteroventral periventricular nucleus of the hypothalamus lie immediately upstream of GnRH neurons and constitute the principal gatekeeper of the reproductive axis. KISS1R activation on GnRH neurons triggers phospholipase C, IP3-mediated calcium release and membrane depolarisation, causing GnRH release into the hypophyseal portal circulation and hence LH and, to a lesser extent, FSH secretion from the pituitary. Loss-of-function mutations in KISS1R cause normosmic isolated hypogonadotropic hypogonadism, which remains the cleanest demonstration that this pathway is obligatory for human puberty and fertility.
Two features matter for how it behaves as a drug. First, kisspeptin acts one step above GnRH, so it stimulates the axis in its own physiological pulsatile pattern rather than clamping the pituitary the way a GnRH agonist depot does - though continuous high-dose exposure still causes tachyphylaxis through KISS1R desensitisation. Second, KISS1R is also expressed in limbic structures including the amygdala, hippocampus and anterior cingulate cortex. That extra-hypothalamic distribution is the anatomical basis for the behavioural effects seen in imaging studies, effects which appear at least partly independent of any downstream rise in testosterone.
Two notes on scope. Kisspeptin-10 and kisspeptin-54 are cleavage products of the same precursor and act at the same receptor, but they are not interchangeable as drugs: their circulating half-lives differ roughly sevenfold, and findings from one cannot simply be transferred to the other. And kisspeptin-10 is grouped here with the melanocortin and reproductive peptides for navigational convenience only. It is not chemically a melanocortin and does not act at melanocortin receptors.
What the research shows
This section has been substantially rewritten following a citation audit, because the previous version attributed four randomised trials to kisspeptin-10 that in fact administered kisspeptin-54.
What has been shown with kisspeptin-10 itself: intravenous administration in healthy men produces rapid, dose-dependent LH release, peaking at a 1 microgram/kg bolus (LH rising from 4.1 to 12.4 IU/L within 30 minutes). Continuous infusion at 1.5 micrograms/kg/hour raised LH pulse frequency from 0.7 to 1.0 pulses per hour and increased secretory burst mass, with a significant rise in testosterone. A separate small study in six men with idiopathic hypogonadotropic hypogonadism found that those sustaining a spontaneous reversal of their condition mounted a GnRH-induced LH pulse in response to kisspeptin while those who relapsed did not, supporting kisspeptin responsiveness as a gate on reproductive activation. Both are careful physiology. Neither is a treatment trial, and between them they involve a few dozen men.
What was NOT shown with kisspeptin-10: the widely cited Imperial College London programme on sexual and emotional brain processing - the 2017 Journal of Clinical Investigation study in 29 healthy men, the 2018 JCI Insight resting-state connectivity study, and the two 2022 and 2023 JAMA Network Open randomised crossover trials in women and men with hypoactive sexual desire disorder - all administered kisspeptin-54 by intravenous infusion at 1 nmol/kg/hour, not kisspeptin-10. Those trials are well conducted and are cited below for completeness, but they are evidence about a different molecule with a half-life roughly seven times longer. Anyone selling kisspeptin-10 on the strength of the 'kisspeptin improves sexual desire' headlines is transferring findings across peptides without justification.
And even taken at face value, none of those trials is a treatment trial. Every one is a single session with an intravenous line, imaging and acute behavioural endpoints. None tested a self-administered formulation, none ran for weeks, and none used validated desire and distress instruments over a treatment period a regulator would require. Kisspeptin-10's four-minute half-life makes intermittent subcutaneous self-injection - the way it is actually marketed - pharmacologically very different again from a continuous infusion of either peptide. There is no published trial of subcutaneous kisspeptin-10 for testosterone support, fertility or libido as sold, and no long-term safety data of any kind.
Evidence assessment
Limited evidence
Downgraded from 'mixed' on audit. The only human trials that actually administered kisspeptin-10 are acute intravenous physiology studies with hormonal endpoints in small samples; every randomised behavioural and functional-MRI trial previously cited on this page administered kisspeptin-54, a different peptide. No trial of any kisspeptin has tested the self-administered subcutaneous product that is sold, and there is no clinical efficacy endpoint anywhere.
Tiers are applied consistently across the library and re-checked when new trials read out. Read the grading method.
Key studies
Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men Limited evidence
Boluses produced dose-dependent LH increases peaking at 1 microgram/kg (4.1 to 12.4 IU/L within 30 minutes); infusion at 1.5 micrograms/kg/hour raised LH pulse frequency from 0.7 to 1.0 pulses/hour and increased secretory burst mass and testosterone.
Kisspeptin Responsiveness Signals Emergence of Reproductive Endocrine Activity: Implications for Human Puberty Limited evidence
Men sustaining reversal mounted a GnRH-induced LH pulse in response to kisspeptin, whereas those who relapsed did not, supporting acquisition of kisspeptin responsiveness as a gate on reproductive activation.
Kisspeptin modulates sexual and emotional brain processing in humans Mixed evidence
Kisspeptin-54 enhanced limbic and paralimbic activity in response to sexual and couple-bonding imagery, correlating with measures of reward, drive and sexual aversion, and attenuated negative mood.
Modulations of human resting brain connectivity by kisspeptin enhance sexual and emotional functions Mixed evidence
Kisspeptin-54 modulated default mode network connectivity and amygdala-cingulate and hippocampus-cingulate pathways, correlating with psychometric measures of sexual and emotional processing.
Effects of Kisspeptin Administration in Women With Hypoactive Sexual Desire Disorder: A Randomized Clinical Trial Mixed evidence
Kisspeptin-54 modulated brain activity in structures involved in sexual and facial-attraction processing relative to placebo, with no reported adverse effects. A single acute infusion, not a treatment trial.
Effects of Kisspeptin on Sexual Brain Processing and Penile Tumescence in Men With Hypoactive Sexual Desire Disorder: A Randomized Clinical Trial Mixed evidence
Kisspeptin-54 modulated activity in sexual-processing brain structures and increased penile tumescence by up to 56% versus placebo during sexual video viewing, over a single session.
Safety
In supervised infusion studies kisspeptin has been well tolerated, with no serious adverse events reported and only mild transient effects. That record needs to be read for what it covers: hours of exposure, under medical supervision, in carefully screened volunteers, delivered intravenously, and in substantial part using kisspeptin-54 rather than kisspeptin-10. It says nothing about repeated subcutaneous self-administration over months.
Unresolved concerns include KISS1R desensitisation with sustained or frequent exposure, which could paradoxically suppress rather than support the reproductive axis - the opposite of the intended effect, and the mechanism by which GnRH agonists become suppressive. The KISS1 gene was originally identified as a metastasis-suppressor, and kisspeptin signalling has context-dependent effects on tumour biology, so effects in people with hormone-sensitive cancers are genuinely unknown. Effects on the female reproductive axis with repeated dosing have not been characterised. And material sold online is not manufactured to pharmaceutical standards, so identity, purity, endotoxin content and sterility are unverified.
Regulatory status
| Jurisdiction | Status |
|---|---|
| United Kingdom | No MHRA marketing authorisation exists. The substantial UK human research programme, conducted principally at Imperial College London, has been carried out under clinical trial authorisations in a hospital setting with intravenous infusion. Supply of kisspeptin-10 for human use outside such a trial is unlawful. |
| United States | Not FDA-approved for any indication and not an approved drug in any formulation. Kisspeptin and its analogues remain investigational. Material sold online is an unregulated research chemical, and the 'for research use only' designation on such products is a legal device permitting sale rather than a safety or quality assurance. |
| WADA (sport) | Prohibited in males at all times. WADA's Prohibited List section S2.2.1 prohibits luteinising hormone and chorionic gonadotrophin together with their releasing factors in males; kisspeptin acts as an LH-releasing factor and falls within that category. BioRx was unable to confirm from the current published list text whether kisspeptin appears among the named example substances, so athletes should consult the current annual list directly rather than rely on this summary. |
Questions
No, and this is the single most important thing to know about this compound. The randomised trials in men and women with low sexual desire, and the brain-imaging studies behind them, all infused kisspeptin-54 - a 54-residue peptide with a half-life around 28 minutes. Kisspeptin-10 is a 10-residue fragment with a half-life around 4 minutes. They act at the same receptor, but they are not the same drug, and no one has repeated those trials with kisspeptin-10. Sellers routinely cite that research for a product it did not test.
Acutely, yes - intravenous infusion in healthy men raises LH pulse frequency and testosterone, and that physiology is well demonstrated. But no study has shown that subcutaneous self-injection, the way it is sold, produces a sustained testosterone increase, and none has run long enough to show any clinical outcome. Given a four-minute half-life, a once-daily injection bears little resemblance to the continuous infusions that were actually studied.
WADA lists substances by what they do, not by whether they are licensed. Kisspeptin stimulates the release of LH, which raises endogenous testosterone, so it falls within the section covering LH and its releasing factors in males, prohibited at all times. Check the current annual Prohibited List for the exact wording - the named examples are revised each year.
No, nowhere, in any form. The randomised trials in hypoactive sexual desire disorder are real and well conducted, but each is a single 75-minute intravenous infusion of kisspeptin-54 in a brain scanner, measuring brain activation and acute physiological response. That is proof of a mechanism, not proof of a treatment - and not proof of anything about kisspeptin-10.
Kisspeptin acts one step further up the chain - on the neurons that release GnRH, rather than on the pituitary directly. In principle that lets the axis keep its own pulsatile rhythm rather than being driven or clamped from outside. In practice, continuous or excessive exposure still desensitises the kisspeptin receptor, so the theoretical advantage of preserving physiological pulsatility depends entirely on a dosing pattern that has never been established for self-administration.