Kisspeptin (kisspeptin-54 and kisspeptin-10)
Kisspeptin: What The Studies Actually Say
It is the body's own switch for sex hormones, and the human studies are real. But they are small, short and mostly one-time doses from one London team. It is not approved anywhere, and there is no human weight-loss trial.
Updated 22 September 2026
Before you read this
This page explains what published studies found. That is all it is. It is not medical advice, and it is not instructions for using anything. Nothing here is meant to find, treat, cure or stop any illness. The compounds discussed on this site, retatrutide included, are not approved by the FDA for use in people. Research compounds are sold for laboratory use only — not for use in humans or animals. A study tells you what happened to the people in it. It does not tell you what would happen to you. What you do with what you read here is your responsibility, so talk to a doctor first. This page is published by Ascend Vials, which sells research compounds.
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Kisspeptin is real. Your body makes it, and without it, puberty does not happen.
What people online say it does is another story: more testosterone, more sex drive, weight loss. Most of that goes further than the studies do.
Here is what the actual research found. Every claim has a link. Read them yourself.
The 30-second version
- Kisspeptin is a hormone your body already makes. It sits at the top of the chain that controls testosterone, estrogen and ovulation.
- One dose raises reproductive hormones for a few hours. In women it depends heavily on the time of the month.
- Given too often, it switches itself off. With shots twice a day, the response shrank by about 90% in two weeks.
- Its best results are in IVF and as a hormone test. The sex-drive studies were single drips in a brain scanner, not real life.
- There is no human weight-loss trial. In women with obesity it did not change how much they ate.
- The studies are small and short, mostly from one London team. It is not approved anywhere, and it is banned in sport.
- Nothing sold online has been shown to match what the studies used. No study has checked.
What it is
Kisspeptin is a natural hormone. Its gene was found in 1996 in Hershey, Pennsylvania, as a gene that stopped melanoma, a skin cancer, from spreading. J Natl Cancer Inst, 1996 And yes, the name is a nod to the town's famous chocolate: Hershey's Kisses. Endocrine Reviews, 2024
Its real job showed up in 2003. Two teams found families with broken copies of the gene for kisspeptin's receptor. The people with two broken copies never went through normal puberty. NEJM, 2003 · PNAS, 2003
In pregnancy, kisspeptin floods the mother's blood, mainly from the placenta. By the third trimester, levels are over 7,000 times those of women who are not pregnant. JCEM, 2003
It comes in different lengths. The number is how many building blocks it has, and all of them share the same active tail. Endocrine Reviews, 2024 Kisspeptin-54 is the main form in human blood. J Clin Invest, 2014 Kisspeptin-10 is the smallest piece that still works fully. JCEM, 2011
It is an experimental compound, not a medicine. Most of the human studies on this page come from one team at Imperial College London. Open the links and check the authors.
How it works
It is a chain of signals. Kisspeptin tells the brain to release GnRH. GnRH tells the pituitary gland to release LH and FSH. Those tell the testes to make testosterone, or the ovaries to make estrogen and release an egg. Endocrine Reviews, 2024
Because it sits one step above GnRH, it only works if the brain's own GnRH cells work. Doctors use that as a test. Neuroendocrinology, 2021
It disappears fast. Half of a dose of kisspeptin-54 is gone from the blood in about 28 minutes. For kisspeptin-10 it is about 3 minutes. JCEM, 2005 · Endocrine Reviews, 2024
The numbers, from the real studies
In men, one dose works, for a few hours. A 2005 study gave 6 healthy men a 90-minute drip of kisspeptin-54 one day and salt water another, without anyone knowing which was which. Average LH was 10.8 on kisspeptin against 4.2 on salt water. Testosterone over the next 3 hours was about 15% higher than on salt water. JCEM, 2005 One shot of kisspeptin-10 into a vein about tripled LH within 30 minutes. JCEM, 2011
In women, timing is everything. The same kisspeptin-54 shot raised LH at every point in the cycle, but by very different amounts. JCEM, 2007
Early in the cycle the rise was close to zero. Just before ovulation it was over 20. JCEM, 2007 Kisspeptin-10 showed an even bigger gap. In women early in their cycle, it did not change these hormones at all, even at the highest amounts tried, while much smaller amounts worked in men. JCEM, 2011
Kisspeptin-10 and kisspeptin-54, side by side
| Kisspeptin-10 | Kisspeptin-54 | |
|---|---|---|
| What it is | Smallest fully active piece | Main form in human blood |
| Half gone from blood in | About 3 minutes | About 28 minutes |
| Total LH over a 3-hour drip, 5 men each (GnRH itself: 34.1) | 10.8 | 14.4 |
| Raised LH in women early in the cycle | No | Yes |
| Longest human study | 12 days, 7 healthy men | 8 weeks, women whose periods had stopped |
| Used in the IVF and sex-drive studies | No | Yes |
| Approved anywhere | No | No |
Read the whole table. Both are weaker than GnRH, the signal they trigger. And most headline results, the IVF babies and the sex-drive scans, used kisspeptin-54. The kisspeptin FDA found pharmacies making was kisspeptin-10. A result for one is not automatically a result for the other.
Sources: Human Reproduction, 2015 · Endocrine Reviews, 2024 · JCEM, 2007 · JCEM, 2011 · Clin Pharmacol Ther, 2010 · Eur J Endocrinol, 2026 · FDA, 2024
Too often, and it switches itself off
If you have heard kisspeptin "boosts testosterone," read this part.
Ten women whose periods had stopped got kisspeptin-54 or salt water as shots twice a day for two weeks. JCEM, 2009
By day 14 the response was about a tenth of day 1. The same pattern shows up wherever it has been tested:
- Healthy men. A nonstop drip of kisspeptin-10 for 5 days let LH and FSH fall back to placebo levels, though testosterone stayed up. With a daily break, LH rises held for 12 days, but shrank. Eur J Endocrinol, 2026
- Monkeys. A nonstop drip raised LH for about 3 hours, then it dropped sharply. Endocrinology, 2006
- A lab-made cousin went all the way. TAK-448 is not kisspeptin, but it hits the same receptor. Given nonstop for 14 days at the higher amounts tested, it pushed healthy men's testosterone below castration level. JCEM, 2014
Shots twice a week for 8 weeks wore the response down only partly. Clin Pharmacol Ther, 2010 None of this is a schedule for anyone to follow. These were small, supervised studies. What they show is the pattern: short bursts push the system, and constant exposure can shut it down. That is the opposite of what someone chasing testosterone wants.
Where the evidence is strongest: IVF and testing
In IVF, a "trigger" shot finishes maturing the eggs. The usual triggers can bring on OHSS, a dangerous overreaction of the ovaries. J Clin Invest, 2014 · Clin Endocrinol, 2018
- 53 women. One kisspeptin-54 shot matured eggs, and 12 healthy babies were born to 10 mothers. There was no comparison group. J Clin Invest, 2014
- 60 women at high risk of OHSS. None got moderate, severe or critical OHSS. Everyone got kisspeptin, so this cannot show it prevented anything. JCEM, 2015
- 62 women, randomized. A second kisspeptin shot beat a salt-water second shot: 71% against 45% reached the target egg yield. Human Reproduction, 2017
- 261 women, looking back. The odds of an OHSS diagnosis were 33.6 times higher after hCG than after kisspeptin. It was not randomized, so other differences may explain part of that. Clin Endocrinol, 2018
What nobody has shown: that kisspeptin means more babies than the standard triggers. This guide found no head-to-head randomized trial, and the 2017 authors called for one. Human Reproduction, 2017
As a test, it has done well. In 42 men, one kisspeptin-54 test perfectly separated those born with a puberty-blocking hormone condition from healthy men. It did better than a GnRH test. Neuroendocrinology, 2021 In 16 children with late puberty, all 8 who responded went on to puberty. All 8 who did not reached 18 without it. JCEM, 2020
Sex drive: brain scans, not real life
Three placebo-controlled trials gave a single 75-minute IV drip of kisspeptin-54 while people watched pictures or videos in a brain scanner.
- 29 healthy young men: brain areas tied to sex and bonding responded more. J Clin Invest, 2017
- 32 women with low desire: their brains processed erotic videos and attractive faces differently. JAMA Netw Open, 2022
- 32 men with low desire: during sexual videos, penile swelling measured by a device rose up to 56% more than on placebo. JAMA Netw Open, 2023
These were one-time drips in a lab, measured with scans and sensors, not real-life desire. JAMA Netw Open, 2022 Nobody has tested whether it changes a sex life over weeks or months.
Weight loss has no human trial
FDA found clinic websites most often market kisspeptin for weight loss and fertility. FDA, 2024 This guide found no human weight-loss trial.
In 17 women with overweight or obesity, a 2-hour kisspeptin drip did not change how much they ate at an all-you-can-eat meal, or how hungry they were. Diabetes Obes Metab, 2023 In 15 healthy men, insulin rose more after a sugar load, but blood sugar, appetite and food eaten did not change. Diabetes Obes Metab, 2018
The rest is mice. Female mice missing the kisspeptin receptor got fat, even while eating less. In other mice, switching the receptor on in the liver reduced fatty liver. Mice are not people. J Clin Invest, 2014 · J Clin Invest, 2022
What to expect
In small, short, supervised studies, few problems were reported. That is not the same as proven safe.
| Study | People | What was reported |
|---|---|---|
| Nasal spray, one dose per visit | 34 | No side effects of any severity |
| Men with low desire, 75-minute drip | 32 | No side effects; more flushing on a questionnaire |
| Pooled brain-scan trials | 95 | No change in anxiety, cortisol, blood pressure or heart rate |
| IVF, high risk of OHSS | 60 | Well tolerated; 2 ectopic pregnancies, 3 miscarriages, 1 stillbirth, called known risks of IVF and pregnancy |
| Healthy women, a week of twice-daily shots | 5 | Periods kept coming, but cycles were about 2 days shorter |
Sources: EBioMedicine, 2025 · JAMA Netw Open, 2023 · JCEM, 2025 · JCEM, 2015 · JCEM, 2013
FDA's 2024 review of kisspeptin-10 adds the bigger gaps. FDA, 2024
- Very few people. About 300 had ever been given it by injection, FDA estimated, and maybe fewer.
- No long-term data. FDA found no trial giving it regularly for more than a day. One 12-day study in 7 men has come out since. Eur J Endocrinol, 2026
- Immune reactions: a risk nobody has tested. FDA said it "may pose a significant risk for immunogenicity," meaning the body could make antibodies against it. No study has checked.
- One adverse-event report. A 17-year-old injected pharmacy-made kisspeptin-10 daily for 6 weeks to raise testosterone. He gained weight, and a form of estrogen rose. FDA said the report had too little information to judge.
Competitive athletes: kisspeptin and drugs that mimic it are banned at all times on the 2026 anti-doping list. WADA list, via NADA Austria
Is it approved?
No. Not anywhere this guide could check. FDA says no country has approved a product containing kisspeptin-10. FDA, 2024
- United States: FDA's approved-drug database had no kisspeptin or metastin product when this guide checked on September 22, 2026. Drugs@FDA FDA lists kisspeptin-10 in "Category 2," ingredients nominated for pharmacy compounding that may present significant safety risks. Some other peptides have moved off that list. As of September 22, 2026, kisspeptin-10 has not. FDA, Category 2 In 2024, FDA's advisory committee voted 0 yes, 11 no on allowing it for pharmacy compounding. Committee minutes
- Europe: no kisspeptin medicine on the European Medicines Agency's list. Single countries were not checked. EMA data, 2026
- UK and elsewhere: the UK studies here were registered research trials. No regulator's database beyond the US and EU was checked. NCT01667406 · ISRCTN17271094
- In the pipeline: none of the 36 kisspeptin studies on ClinicalTrials.gov is the kind of large trial that gets a drug approved. Two small trials of kisspeptin-10 are recruiting at Massachusetts General Hospital. Search · NCT05896293 · NCT07224438
What is still unknown
- Long-term safety. The longest human studies ran 8 weeks and 12 days. Clin Pharmacol Ther, 2010 · Eur J Endocrinol, 2026
- Whether repeated use brings back periods or fertility, beyond short hormone bumps. NCT07224438
- Whether it can hold testosterone up for months. FDA found no such trial. FDA, 2024
- Bone. A marker of bone building rose up to 20% during a 90-minute study. Nobody measured bone density or fractures. JCEM, 2022
- Cancer. Kisspeptin was found as a melanoma blocker, but in mice its receptor helped a breast cancer grow and spread. There is no human evidence either way. Nature, 2001 · Cell Death Dis, 2020
What is in the bottle is not what was studied
One more thing.
Every result on this page where people were given kisspeptin came from a research study. Run by doctors. Given under supervision. Blood checked as they went.
No study has ever shown that a product sold online as "kisspeptin" or "kisspeptin-10" is the same thing. Not the same purity. Not the same strength. Not even proof it is the same molecule. Nothing sold online has been tested against what these studies used.
Several of FDA's worries about kisspeptin-10 were about exactly this: impurities, trouble confirming what the ingredient really is, and no official quality standard. FDA, 2024
So take every number on this page for what it is. It describes the kisspeptin used in those studies. It describes nothing else.
How to check a number yourself
You are going to see more claims about kisspeptin. In a reel. In a comment. On somebody's store page.
Here is how to tell a real one from a marketing one. Five questions. About ten seconds each.
1. Is there a link to a study?
No link means it is a claim, not a result. Search pubmed.gov yourself, under its older name too: metastin. FDA quoted a site selling kisspeptin-10 that said it improves thinking. This guide found no human study behind that. FDA, 2024
2. Which kisspeptin was it?
Kisspeptin-54, kisspeptin-10 and lab-made analogs like TAK-448 and MVT-602 are different molecules, and they do not act the same. J Clin Invest, 2020 A result for one is not a result for another.
3. Did it measure the thing being claimed?
A higher LH reading for an afternoon is not higher testosterone for months. A brain scan is not a better sex life.
4. How long did it run, and how often was it given?
With kisspeptin, this can flip the result. One shot works. Twice a day for two weeks, the response nearly vanished.
5. Was there a group that got nothing?
Two of the IVF studies above had none, so they cannot say how kisspeptin compares with the usual trigger. The sex-drive trials did.
Now run those five on this page
Every number above links to the paper it came from. Each study says which form it used. The ones that only measured hormones or brain scans say so. The switch-off numbers are in the second chart. The IVF studies without a comparison group are marked.
The big online claims, weight loss, lasting testosterone, a better sex life, have no study showing them in people.
That is the whole difference: a number you can check, and a number you are asked to believe.
This page has a date on it, near the top. When the Massachusetts General Hospital trials report, this page changes.
Read the studies yourself
- Where it came from: discovery, J Natl Cancer Inst 1996 · puberty genes, NEJM 2003 · puberty genes, PNAS 2003 · pregnancy levels, JCEM 2003 · melanoma in mice, Nature 2001
- Review, Endocrine Reviews 2024 — free to read; forms, half-lives, the Hershey name
- Hormones: 6 men, JCEM 2005 · women by cycle phase, JCEM 2007 · kisspeptin-10 in men, JCEM 2011 · men against women, JCEM 2011 · 10 vs 54 vs GnRH, Human Reproduction 2015
- Switching off: twice daily, JCEM 2009 · twice weekly, Clin Pharmacol Ther 2010 · 12 days, Eur J Endocrinol 2026 · monkeys, Endocrinology 2006
- IVF: 53 women, J Clin Invest 2014 (free to read; also on PubMed) · high OHSS risk, JCEM 2015 (free full text) · second dose, Human Reproduction 2017 · three triggers compared, Clin Endocrinol 2018
- As a test: men, Neuroendocrinology 2021 · children, JCEM 2020
- Sex drive and mood: men, J Clin Invest 2017 · women with low desire, JAMA Netw Open 2022 · men with low desire, JAMA Netw Open 2023 · anxiety, JCEM 2025
- Other safety: nasal spray, EBioMedicine 2025 · healthy women's cycles, JCEM 2013
- Weight, bone, cancer: appetite in women, Diabetes Obes Metab 2023 · insulin in men, Diabetes Obes Metab 2018 · bone, JCEM 2022 · mice without the receptor, J Clin Invest 2014 · fatty liver in mice, J Clin Invest 2022 · breast cancer in mice, Cell Death Dis 2020
- Analogs, not kisspeptin: TAK-448, JCEM 2014 · MVT-602, J Clin Invest 2020
- Status: FDA evaluation, 2024 · Drugs@FDA · FDA Category 2 · committee minutes, 2024 · EMA data · WADA 2026 list, via NADA Austria
- Trials: all kisspeptin studies · NCT01667406 · ISRCTN17271094 · NCT05896293 · NCT07224438
Everything above describes what studies gave to enrolled volunteers and patients under a doctor's care, or to lab animals and cells. This is not advice, a plan, or instructions. Kisspeptin is not an approved medicine anywhere this guide could check. Research compounds are not for human or animal use.