Kisspeptin-10

Kisspeptin-10, often written KP-10, is the last ten amino acids of kisspeptin, a signalling protein made by the KISS1 gene in the hypothalamus, which is the part of the brain that controls hormone output. That short tail is the part that binds the receptor, so it behaves like the full-length molecule. Its job in the body is to switch on the neurons that release gonadotrophin-releasing hormone (GnRH), the pulse signal that tells the pituitary gland to put out luteinising hormone (LH) and follicle-stimulating hormone (FSH), which in turn tell the testes to make testosterone or the ovaries to mature an egg. Almost everything known about it in people comes from small hospital physiology studies, usually four to fifteen volunteers, in which it was given by intravenous drip or a single intravenous injection and blood hormones were sampled for a few hours. It is not an approved medicine anywhere, and the US Food and Drug Administration placed kisspeptin-10 on its list of bulk drug substances that may present significant safety risks in September 2023.

• Raising luteinising hormone and testosterone in men, which a bolus of kisspeptin-10 does reliably over about 30 minutes (George 2011)
• Investigating low testosterone in men with type 2 diabetes, where kisspeptin-10 still raised LH and testosterone, suggesting the pituitary and testes were working and the problem sat higher up (George 2013)
• Mapping how the GnRH pulse generator is timed, since a single kisspeptin-10 bolus triggers an immediate LH pulse and resets the clock (Chan 2011)
• Triggering egg maturation in fertility treatment and studying low sexual desire, though those trials used the longer kisspeptin-54 isoform rather than kisspeptin-10 (Mills 2023)
• Off-label use in male hormone-optimisation circles as a testosterone-restoration or libido compound, which is not what any of the published trials were designed to test

Think of your hormone system as a factory where the hypothalamus is the foreman, the pituitary is the dispatcher and the testes or ovaries are the production line. Testosterone injections skip the whole chain and drop finished product on the loading dock, which is why the foreman stops giving orders. Kisspeptin-10 goes to the other end and taps the foreman on the shoulder, so the order still travels down the normal chain. The catch found in the trials is that the tap is brief and the foreman stops responding if you keep tapping: repeated dosing desensitised the system rather than keeping it switched on (Jayasena 2009).

1. Minutes 0-30In healthy men an intravenous bolus raised LH from about 4 to about 12 international units per litre by 30 minutes, with the largest response at 1 microgram per kilogram (George 2011).
2. Hours 1-12During a continuous infusion, LH pulse frequency rose from roughly 0.7 to 1.0 pulses per hour and testosterone climbed from about 17 to 24 nanomoles per litre on the higher-dose infusion (George 2011). In men with type 2 diabetes an 11-hour infusion raised testosterone from about 8.5 to 11.4 nanomoles per litre (George 2013).
3. Day 1Twice-daily subcutaneous kisspeptin-54 in women with hypothalamic amenorrhoea produced a large first-day rise in LH and FSH (Jayasena 2009).
4. Days 2-14In that same study the response collapsed by day 14, from an LH rise of about 24 down to about 2.5 international units per litre, which the authors called tachyphylaxis, meaning the receptor stops answering with repeated dosing (Jayasena 2009).
5. Beyond 2 wksNo human study located ran longer than about two weeks of repeated dosing, so there is no evidence base for the 8-to-12-week cycles used off-label, and no human data on what repeated subcutaneous kisspeptin-10 does to testosterone over months.

• The human studies located reported no adverse events; one 2025 paper states that kisspeptin had previously been given intravenously and subcutaneously to over 1000 people without any observed adverse effects, and that intranasal dosing was tolerated by all participants with no side effects of any severity (Mills 2025). That is not the same as none existing, because these were short exposures in screened volunteers
• Loss of effect with repeated dosing is the best-documented problem: the gonadotrophin response fell sharply by day 14 of twice-daily subcutaneous injection in women (Jayasena 2009)
• Predictable downstream hormone swings, since the intended action is a surge in LH, FSH and then testosterone or oestradiol; in women the effect depends heavily on cycle phase and was absent in the follicular phase in one study (Jayasena 2011)
• The US Food and Drug Administration has stated that compounded drugs containing kisspeptin-10 may pose risk for immunogenicity for certain routes of administration, meaning an immune reaction raised against the peptide, and may have complexities with regard to peptide-related impurities and characterisation of the active ingredient
• Injection-site reactions are not characterised in the human literature located, because nearly every human study used intravenous infusion or a single intravenous bolus rather than the repeated subcutaneous injection used off-label
• Because published human exposure is short-duration and in the low thousands at most, uncommon or delayed adverse effects would not have been detected

• You are pregnant, trying to conceive without medical supervision, or breastfeeding; kisspeptin acts directly on the reproductive axis and on placental function, and no reproductive safety data exists for self-administered kisspeptin-10
• You have a hormone-sensitive cancer or a history of one, including prostate or breast cancer; raising LH, testosterone or oestradiol is the opposite of what androgen- or oestrogen-deprivation treatment is meant to do
• You have an undiagnosed cause of low testosterone. Kisspeptin-10 was used in research precisely to tell hypothalamic causes from pituitary and testicular ones (George 2013); self-treating skips the workup that would find a pituitary tumour, haemochromatosis or sleep apnoea
• You are a woman with irregular cycles, polycystic ovary syndrome or hypothalamic amenorrhoea and are not under a specialist; the female response to kisspeptin-10 depends on cycle phase and was absent in the follicular phase in one study (Jayasena 2011)
• You are a competitive athlete under the World Anti-Doping Agency code; kisspeptin and its agonist analogues are named in section S2.2.1 of the 2026 Prohibited List as testosterone-stimulating peptides prohibited in males at all times
• You are under 18, since this is the pathway that starts puberty, or you are not working with a physician who knows you are taking it and can monitor hormones

• Assuming the off-label dose maps onto the trial dose. Every human study located used intravenous dosing: single boluses of 0.01 to 3.0 micrograms per kilogram, or infusions of 0.1 to 1.0 nanomoles per kilogram per hour (George 2011, Narayanaswamy 2015). A 100 to 200 microgram subcutaneous injection is a different route with a different absorption profile, and nobody has published what it does.
• Dosing frequently and expecting a sustained effect. The one repeated-dosing study located found the hormonal response nearly gone by day 14 (Jayasena 2009), so adding injections per week is the change most likely to make the compound stop working.
• Treating kisspeptin-10 as a drop-in replacement for gonadorelin or human chorionic gonadotrophin alongside testosterone replacement therapy. When kisspeptin-10, kisspeptin-54 and GnRH were compared head to head in the same men, GnRH produced roughly three-fold higher LH and FSH than kisspeptin-10 (Narayanaswamy 2015).
• Ignoring cycle phase in women. Kisspeptin-10 raised gonadotrophins in men and in women during the preovulatory phase but not in women during the follicular phase (Jayasena 2011), so a flat weekly schedule ignores the one variable that determined whether it worked.
• Reconstitution and storage errors. Use bacteriostatic water, run it slowly down the vial wall and swirl rather than shake; keep the lyophilised powder cold and dark, refrigerate after reconstitution, and discard on the timeline your pharmacist gives instead of stretching a 10 mg vial over months at room temperature.