Kisspeptin Peptide: What It Does in the HPG Axis, With a Dosage and Frequency Chart

Kisspeptin is unusual among the compounds the Bureau covers because the human evidence came first. Most research peptides are rodent findings that the market ran ahead of. This one was discovered through human genetics, has been given to people in registered clinical trials at a London teaching hospital for two decades, and has a plausible route to becoming an approved fertility drug. What the research market sells, however, is not quite what those trials used, and that gap is the most useful thing this page can explain.

Below: what kisspeptin is and where the odd name comes from, how it drives LH and FSH from the top of the hypothalamic pituitary gonadal axis, why kisspeptin-10 and kisspeptin-54 are not interchangeable, what the human trials actually measured, a dosage and frequency chart, the vial arithmetic, and how it differs from hCG and from PT-141, both of which the Bureau already covers.

What Kisspeptin Is, and the Name

Kisspeptin is the product of the KISS1 gene, which was not discovered by reproductive biologists at all. It was identified in 1996 as a metastasis suppressor gene in melanoma, at a laboratory in Hershey, Pennsylvania, and the researchers named it after the town's most famous product. The protein was originally called metastin. Only years later did anyone work out that its real day job is running puberty.

The gene encodes a 145 amino acid precursor that is cleaved into several fragments. The longest is kisspeptin-54, the original metastin. Shorter ones follow at 14, 13 and 10 residues. All of them share the same C-terminal decapeptide, which is the part that binds the receptor, so all of them are biologically active in the same way. Kisspeptin-10 is the shortest fully active fragment, which is why it is the one synthesised and sold.

How Kisspeptin Drives LH and FSH

The hypothalamic pituitary gonadal axis has three floors. The hypothalamus releases gonadotropin releasing hormone in pulses; the pituitary answers with luteinising hormone and follicle stimulating hormone; the testes or ovaries answer with testosterone or oestradiol. Kisspeptin sits above all of it.

It binds KISS1R, a receptor formerly called GPR54, which is expressed on the GnRH neurons themselves. Activating it makes those neurons fire and release GnRH, and everything downstream follows. In the arcuate nucleus the kisspeptin neurons co-express neurokinin B and dynorphin, which is why they are known as KNDy neurons, and that cluster is currently the best candidate for the pulse generator that gives GnRH its rhythm.

The evidence that this is the master switch is genetic, not pharmacological, which is what makes it strong. Two groups reported in 2003 that people born with loss of function mutations in GPR54 fail to go through puberty, presenting as normosmic idiopathic hypogonadotropic hypogonadism: the hypothalamus, pituitary and gonads are all intact, and the starting signal never arrives. An activating mutation produces the opposite, central precocious puberty. No amount of dosing data demonstrates a mechanism as cleanly as that pair of natural experiments does.

One consequence deserves stating early because it determines who this compound can possibly help. Kisspeptin acts at the top of an intact chain. If the pituitary is suppressed, or the gonads are not responsive, pushing on the switch above them does nothing. That is the structural difference from hCG, covered further down.

Kisspeptin-10 Versus Kisspeptin-54

This is where the market and the literature diverge, and it is the most practically important section on the page.

Both fragments end in the same decapeptide and hit the same receptor, so the difference is not potency at the target. It is exposure time. Kisspeptin-10 clears in minutes, which is fine for a study designed to measure an LH pulse in a controlled unit with a cannula in the arm, and awkward for anyone injecting once and expecting a sustained effect. When a protocol quotes a figure that came from a kisspeptin-54 trial and applies it to a kisspeptin-10 vial, it is quietly assuming the two are the same drug. They are the same signal delivered over very different timeframes.

What the Human Research Actually Showed

Most of the clinical work comes from one group, Waljit Dhillo's at Imperial College London, and it falls into three lines.

The acute hormone response. From 2005 onwards, studies reported that giving kisspeptin to healthy men raises LH within minutes, and that the response in women depends on where they are in the menstrual cycle, being largest in the preovulatory phase. The switch works, in people, at doses that are tolerated.

The IVF trigger. The most clinically developed use. In standard IVF, hCG triggers final oocyte maturation and is the main driver of ovarian hyperstimulation syndrome because it lingers. Kisspeptin-54 triggers the woman's own short lived LH surge instead. Trials published from 2014 onwards, including work in women at high risk of hyperstimulation, reported successful oocyte maturation and live births with a kisspeptin trigger. That is a genuine clinical endpoint, and it is the strongest evidence any compound on this site has for doing what its mechanism says it should.

Sexual and emotional brain processing. A 2017 study reported that kisspeptin enhanced activity in limbic brain regions in response to sexual and couple-bonding images in healthy men. Randomised, placebo controlled crossover studies followed in men and then women with hypoactive sexual desire disorder, reporting changes in sexual brain processing and, in the men, increased penile tumescence against placebo. These were single-session mechanistic studies of around thirty participants. They are not multi-week treatment trials with a clinical endpoint, and the difference matters when a vendor page cites them.

The fourth finding is the one that should shape any schedule, and it is the least quoted. In women with hypothalamic amenorrhoea, twice daily administration of kisspeptin-54 blunted the LH response within roughly two weeks, while less frequent dosing preserved it. The receptor desensitises to continuous or near-continuous exposure. That is exactly what you would expect from a system that normally works in pulses, and it means the intuition that more frequent is better is wrong here in a way it is not wrong for most compounds on this site.

Kisspeptin Dosage Chart

What follows describes what appears in practice, presented as research use information rather than instructions. The published human studies quote doses in nmol per kilogram by infusion or as a single trigger injection, not micrograms by repeated subcutaneous injection, so the figures below are conventions. For scale, the single subcutaneous trigger doses in the IVF work sat in the low nmol/kg range, which for a 70 kilogram adult and kisspeptin-54's molecular weight works out at roughly one to five milligrams in one shot. That is one to two orders of magnitude above anything in the table, and it was given once.

The frequency column is doing more work than the amount column, and it is the part with actual human evidence behind it. Daily and twice daily schedules circulate, and the desensitisation finding above is a direct argument against them. Two to three times a week on non-consecutive days is the shape that fits what the literature shows about how this receptor behaves, and it is also the shape that fits a system evolved to respond to pulses rather than to a plateau. Nothing in the published work validates any specific milligram figure for repeated subcutaneous kisspeptin-10, and this page is not going to pretend otherwise.

Turning a Vial Into Syringe Units

Kisspeptin has the same units trap as BPC-157. Amounts are quoted in micrograms and vials are labelled in milligrams, and confusing the two is a thousandfold error in the dangerous direction. One milligram is 1,000 micrograms. A 100 mcg dose is one hundredth of a 10 mg vial.

The arithmetic: concentration is vial milligrams divided by millilitres of bacteriostatic water added, volume per dose is the amount divided by that concentration, and units on a U-100 insulin syringe are that volume in millilitres multiplied by 100. The reconstitution guide covers the mixing and the bac water guide covers the diluent.

Avoid the concentrated rows. A 10 mg vial in 2 mL puts 100 mcg at two units, where a one unit misread is a 50 percent error, and no insulin syringe is built to be read that finely. Diluting to 1 mg/mL puts the same dose at ten units and costs nothing but bacteriostatic water and fridge space, provided the vial has the headroom. A reconstituted vial keeps roughly four weeks refrigerated, per the storage guide, and at two or three injections a week a 10 mg vial at 100 mcg will long outlive that, so buy the smaller vial if the vendor offers one. The injection guide covers needles, angle and site rotation.

How It Differs From hCG and From PT-141

Three compounds get shelved together as "libido and hormone peptides" and they work at three different places.

The takeaway is blunt. Anyone whose axis is shut down by exogenous testosterone has nothing for kisspeptin to act on, and hCG is the compound that fits. Anyone whose interest is acute arousal rather than hormone production is describing PT-141. Kisspeptin is for the case in between: an intact but sluggish axis, or the central processing side the Imperial College imaging work points at. The erectile dysfunction page compares the options when that is the goal.

Side Effects and Who It Is Not For

Kisspeptin has a better safety record than most compounds here, with the caveat that the record comes from supervised single doses and short courses in clinical units. The IVF trigger studies are the largest dataset and reported it as well tolerated; the point of that work was that a kisspeptin trigger carried a lower hyperstimulation risk than hCG, which is a safety finding in its favour. Injection site reactions, headache and nausea are the common minor reports.

The pharmacological caveat is desensitisation: dose it too often and the response fades. The population caveats are firmer. Kisspeptin rises enormously in pregnancy, where the placenta produces it, and nothing outside a trial setting has been studied in anyone pregnant or trying to conceive outside supervised IVF. It manipulates the reproductive axis directly, so it is not a neutral addition to an existing hormonal protocol, and anyone with a pituitary or reproductive condition is in territory where a clinician and a blood test are the relevant tools, not a research vial. The side effects guide and the peptides for women page cover the surrounding ground.

On regulatory status, once and plainly: kisspeptin is not approved as a medicine in any jurisdiction. Kisspeptin-54 has been given to people under investigational protocols in registered trials, which is a different thing from approval, and what the research market sells is kisspeptin-10 as a research chemical. The legal status guide has the framework.

Stacking

Kisspeptin is an upstream signal, so the sensible pairings are ones that do not fight it. Anything that suppresses the pituitary defeats the mechanism entirely, which rules out running it alongside exogenous testosterone and expecting a result.

The pairing that appears most often is with PT-141, on the logic that one works on the hormonal axis over weeks and the other on arousal pathways acutely, so they do not compete for the same receptor. Pantheon sells a PT-141 and kisspeptin blend vial, which tells you how common the combination is. The oxytocin page covers the third compound in the same conversations, and the secretagogues on the ipamorelin guide run on a separate axis that neither helps nor hinders.

What kisspeptin does not do is fat loss or muscle growth. It has no metabolic mechanism of its own, and the compounds that do are on the weight loss peptides page and the 5-Amino-1MQ page. Testosterone rising within the normal range downstream is not an anabolic effect, and nobody has measured body composition in a kisspeptin trial.

Where to Buy Kisspeptin

Disclosure. Links in this section may earn the Bureau a commission. The scorecard weighs documentation, consistency, shipping and price, and the method is on the vendor scorecard page. Every vendor below sells kisspeptin-10 unless its listing says otherwise, which is the fragment to expect.

• Amino Club: the vendor Bureau readers order from most this year, with the most detailed published testing policy of the five we score, including net peptide content, which is the number that decides whether your 100 mcg is really 100 mcg. Product pages sit behind a researcher verification screen, so the link shows the live price. Code 100 takes 20% off a first order. Amino Club review.
• Pantheon Peptides: lists kisspeptin-10 explicitly rather than as an unqualified "kisspeptin", which is the labelling you want, and also sells a PT-141 and kisspeptin blend. COAs are published per batch on a Lab Results page linked from the product pages. Pantheon review.
• PSPeptides: the one to use outside the United States, shipping to Canada, the EU, the UK and Australia, with a batch-specific COA in every order. Code PEPTIDEBUREAU takes 10% off and keeps the order counted for the Bureau.

Two things to check on the certificate, and they matter more here than for most compounds. The first is which fragment you are buying: a listing that says only "kisspeptin" is almost certainly kisspeptin-10, but the mass on the certificate settles it, roughly 1,300 daltons against roughly 5,900. The second is net peptide content, because lyophilised powder is typically 70 to 90 percent peptide by mass with the balance water and counterions, and when your dose is 100 micrograms that difference is not rounding. The testing guide covers how to read both, and the buying guide covers the rest.

Key Takeaways

• Kisspeptin is the product of KISS1, named after Hershey's Kisses, and was found as a metastasis suppressor before anyone knew it ran puberty
• It acts on KISS1R on hypothalamic GnRH neurons, at the top of the reproductive axis, releasing GnRH and then LH and FSH, and the mechanism is proved by genetics: receptor loss of function means no puberty, an activating mutation means puberty far too early
• Kisspeptin-54 lasts roughly half an hour and carries most of the durable human data; kisspeptin-10 lasts minutes and is what the market sells
• The strongest clinical evidence is the IVF trigger work, where a kisspeptin trigger produced oocyte maturation and live births with lower hyperstimulation risk than hCG
• The libido findings are real but small: brain imaging and tumescence in single-session crossover studies of about thirty people
• Twice daily dosing blunted the response within two weeks in published work, so intermittent dosing two or three times weekly is the shape the evidence supports
• It needs an intact axis, so it does nothing for someone suppressed by exogenous testosterone, which is hCG's territory
• Doses are in micrograms and vials in milligrams; dilute to 1 mg/mL so 100 mcg reads as ten units rather than two

Frequently Asked Questions

What does kisspeptin do?

Kisspeptin is the switch at the top of the reproductive axis. It binds KISS1R, a receptor sitting on the GnRH neurons in the hypothalamus, and makes them release gonadotropin releasing hormone. That drives the pituitary to release LH and FSH, which drive the testes or ovaries. Its central role was established by genetics rather than by dosing studies: people born with loss of function mutations in the receptor do not go through puberty, and an activating mutation causes puberty far too early. In human trials, giving kisspeptin raises LH within minutes.

What is the kisspeptin dosage?

The research market sells kisspeptin-10, and the amount in circulation for it is 100 mcg subcutaneously, with 50 to 200 mcg the reported range, two or three times a week rather than daily, in blocks of four to eight weeks. The frequency matters more than the number here and it is the one part with human evidence behind it: twice daily dosing of kisspeptin-54 blunted the LH response within about two weeks in published work, while intermittent dosing kept it. The published human studies quote doses in nmol/kg by infusion, not mcg by subcutaneous injection, so the milligram figures in circulation are convention rather than measurement.

What is the difference between kisspeptin-10 and kisspeptin-54?

Length and how long they last. Both come from the same KISS1 precursor and both end in the same active decapeptide, so they hit the same receptor. Kisspeptin-54, also called metastin, weighs about 5,900 daltons and has a reported half life of roughly 28 minutes. Kisspeptin-10 weighs about 1,300 and clears in a few minutes. Almost all the durable human work, including the IVF trigger studies, used kisspeptin-54, while almost everything the research market sells is kisspeptin-10. That mismatch is the single most important thing to know before reading any kisspeptin protocol.

How is kisspeptin different from hCG?

They act at opposite ends of the same axis. hCG bypasses the brain entirely and stimulates the LH receptor on the gonad directly, with a long half life, which is why it keeps working when the pituitary is switched off by exogenous testosterone. Kisspeptin acts at the top, on the GnRH neurons, so it needs an intact hypothalamus, pituitary and gonad to do anything at all. The practical consequence: for someone whose own axis is suppressed by testosterone, kisspeptin has nothing to work with. hCG is also an approved drug with decades of clinical use behind it, and kisspeptin is not.

Does kisspeptin increase libido?

The human work on this is real but small and mechanistic. Randomised, placebo controlled crossover studies from Imperial College London reported that kisspeptin administration enhanced brain activity in limbic regions in response to sexual and bonding stimuli, and in men with hypoactive sexual desire disorder it increased penile tumescence against placebo. Companion work in women with the same diagnosis reported changes in sexual brain processing. These were single-session studies in around thirty people measuring brain and physiological responses, not multi-week treatment trials with a clinical endpoint. The direction is consistent and the evidence base is thin.

Research use only. The compounds discussed are sold as research chemicals and are not approved for human use. Nothing here is medical advice. More compound guides are indexed on the guides page.