Kisspeptin-10 is the last ten amino acids of kisspeptin-54, the full-length peptide the KISS1 gene produces. Its sequence is Tyr-Asn-Trp-Asn-Ser-Phe-Gly-Leu-Arg-Phe with an amidated tail, and it is the shortest piece of the parent molecule that still activates the kisspeptin receptor with full intrinsic activity. That is both what makes it useful and where its limits come from: it is the working end of a larger peptide, cut away from the rest, and in people it clears from the bloodstream with a half-life of about four minutes.
This page is about the fragment itself: what it is, what was measured when people were given it, and why four minutes shapes everything else. For what the peptide does in the body generally, what does kisspeptin do covers the axis.
What kisspeptin-10 is, precisely
The KISS1 gene encodes a precursor that is cleaved and amidated into a 54-amino-acid peptide, isolated from human placenta in 2001 and named metastin, because KiSS-1 had been identified as a metastasis-suppressor gene for melanoma (Ohtaki et al., Nature 2001). Forms of 54, 14, 13 and 10 residues all share the same C-terminal ten amino acids and the same Arg-Phe-amide ending (Kotani et al., J Biol Chem 2001; d'Anglemont de Tassigny et al., PLoS One 2017). That shared tail is the receptor-binding business end, which is why the ten-residue version works at all.
Three names describe one molecule, and seeing all three is not evidence of three products: kisspeptin-10, metastin 45–54 (numbered within the 54-mer) and kisspeptin-112–121 (numbered from the precursor). The receptor is KISS1R, still widely written as GPR54.
Where kisspeptin-10 sits in the reproductive axis
One rung above GnRH. Kisspeptin binds KISS1R on GnRH neurons in the hypothalamus; those neurons fire, GnRH reaches the pituitary, and LH and FSH follow. It signals a hormone system rather than replacing a hormone.
The cleanest human demonstration used the decapeptide directly. In 13 healthy adult men, a single intravenous bolus induced an immediate LH pulse regardless of when the previous natural pulse had occurred, and induced pulses were larger than endogenous ones (amplitude 5.0 ± 1.0 versus 2.1 ± 0.3 mIU/mL, P = 0.02). It also delayed the next natural pulse — the fragment reset the clock (Chan et al., J Clin Endocrinol Metab 2011).
What human studies of kisspeptin-10 have measured
The human dataset is small, specific and mostly intravenous.
Dose-response in men. Intravenous boluses from 0.01 to 3.0 µg/kg raised serum LH dose-dependently, with maximal stimulation at 1 µg/kg (4.1 ± 0.4 to 12.4 ± 1.7 IU/L at 30 minutes, n = 6). The 3 µg/kg dose produced a smaller response than 1 µg/kg. A 22.5-hour infusion raised testosterone from 16.6 ± 2.4 to 24.0 ± 2.5 nmol/L, and a lower infusion rate raised LH pulse frequency from 0.7 ± 0.1 to 1.0 ± 0.2 pulses per hour (George et al., J Clin Endocrinol Metab 2011).
Men and women responded differently. In healthy men, LH rose after intravenous boluses as low as 0.3 nmol/kg. In healthy women during the follicular phase, no change in gonadotropins was seen after an intravenous bolus up to 10 nmol/kg, a subcutaneous bolus up to 32 nmol/kg, or an infusion up to 720 pmol/kg per minute — while the same 10 nmol/kg intravenous bolus did raise LH and FSH in women during the preovulatory phase (Jayasena et al., J Clin Endocrinol Metab 2011).
Age changed the downstream half. A 1 µg/kg intravenous bolus raised LH in adult, middle-aged and older men alike, but testosterone rose only in the adult group (Ullah et al., Andrologia 2019).
Group sizes are four to six people: physiology experiments measuring hormone release over hours, not outcome trials.
The desire and brain-imaging trials used kisspeptin-54
That matters, because those trials are the ones most often quoted on pages selling the decapeptide. In 29 healthy men, kisspeptin enhanced limbic brain activity in response to sexual and couple-bonding stimuli and attenuated negative mood (Comninos et al., J Clin Invest 2017). Two randomised, double-blind, placebo-controlled crossover trials in people with hypoactive sexual desire disorder followed (Thurston et al., JAMA Netw Open 2022; Mills et al., JAMA Netw Open 2023).
All three used intravenous kisspeptin-54 — the full-length peptide, infused at 1 nmol/kg per hour over 75 minutes in the two crossover trials, in a research unit, with outcomes measured as brain activity and questionnaire scores over hours. None used kisspeptin-10. PT-141 is worth naming only to keep the categories straight: it acts at melanocortin receptors, a different central pathway, which is why both sit in Mood & Libido without working the same way.
A four-minute half-life
| Peptide | Half-life | Setting |
|---|---|---|
| Kisspeptin-10 | 3.8 ± 0.3 min (men), 4.1 ± 0.4 min (women) | Human, after intravenous infusion |
| Kisspeptin-54 | 27.6 ± 1.1 min | Human, 90-minute intravenous infusion |
| Kisspeptin-10 | ≈ 4 min | Mouse |
| Kisspeptin-54 | ≈ 32 min | Mouse |
The human figures come from frequent blood sampling immediately after infusions were stopped, and are about seven times shorter than kisspeptin-54 measured the same way (Jayasena 2011; Dhillo et al., J Clin Endocrinol Metab 2005). The mouse pair comes from d'Anglemont de Tassigny 2017.
A short half-life is not the same as a short effect. After intravenous boluses in men, plasma kisspeptin peaked around 10 minutes and was undetectable by 50 at the highest dose tested, while LH peaked at 30–40 minutes and testosterone at 150–180. The molecule leaves; the cascade it set off keeps running.
The mouse work cautions against reading too much into clearance alone. Repeating kisspeptin-10 injections every 10 minutes for an hour did not reproduce the sustained LH rise a single kisspeptin-54 injection produced, and only kisspeptin-54 activated GnRH neurons behind the blood-brain barrier.
Why route and rhythm matter more than the number
Route first. In the study above, subcutaneous kisspeptin-10 at up to 32 nmol/kg raised measurable peptide in follicular-phase women's blood but moved no gonadotropins; the authors' proposed explanation was breakdown of the fragment in subcutaneous tissue. Compounded kisspeptin is dispensed as a subcutaneous injection, which makes this worth raising at a visit rather than discovering later.
Rhythm second, and the primate work here is unusually clean. Hourly one-minute infusions of 2 µg kisspeptin-10 for 48 hours in juvenile male rhesus monkeys produced a sustained train of LH discharges, abolished by a GnRH-receptor antagonist (Plant et al., Endocrinology 2006). Continuous infusion in the same species did the opposite: a brisk LH rise for about three hours, then a sharp fall, after which a kisspeptin-10 bolus no longer worked while GnRH still did — the receptor had desensitised, not the pituitary (Seminara et al., Endocrinology 2006).
None of these figures is a protocol. They are trial parameters, in named species, by named routes, under monitoring. Dose, frequency and route on a prescription are set by the prescribing provider.
What a kisspeptin-10 prescription actually is
Kisspeptin dispensed through Promise is prepared as a compounded medication, which is different from an FDA-approved product: the preparation offered here is not FDA-approved. Compounded medications are not reviewed by the FDA for safety, effectiveness, or quality. No approved kisspeptin medicine exists at any peptide length.
Regulatory status is one input into a prescribing decision rather than the whole of it, and a licensed provider may still prescribe a compounded preparation where they judge it appropriate — that decision is between you and your doctor.
The other route is vials sold online without a prescription and labelled as laboratory material, with no clinician attached and no accountability for what is in them. A licensed provider reviews every request, prescribes only where kisspeptin-10 is appropriate for you, and can decline — not everyone qualifies.
This article is for general education and is not medical advice, a diagnosis, or a treatment recommendation. Talk to a licensed clinician about your own health.