What it is
Kisspeptin is a hormone the body makes in the hypothalamus. It is the signal that sits at the very top of the reproductive system, above GnRH, LH and FSH. People and animals born without a working kisspeptin receptor do not go through puberty, which is how its role was discovered.
The name covers a small family of peptides cut from the same precursor protein. Kisspeptin-54 is the longest form and the one most used in human research. Kisspeptin-10 is the shortest fragment that still works and is what research-market vials usually contain. All forms share the same active tail that binds the receptor.
How it works
Kisspeptin binds its receptor (KISS1R) on GnRH neurons. Those neurons release GnRH in pulses, the pituitary answers with LH and FSH, and those hormones drive the testes or ovaries.
That places kisspeptin one step above gonadorelin, which is synthetic GnRH, and two steps above hCG, which mimics LH directly at the gonads. Because kisspeptin works through the body's own GnRH release, the downstream response still depends on a functioning hypothalamus-pituitary axis.
Kisspeptin signalling also reaches limbic brain areas involved in emotion and sexual motivation, which is why the Imperial College group went on to test it on desire rather than only on hormones.
What the research found
Most of the human evidence comes from one research group at Imperial College London and Imperial College Healthcare NHS Trust, led by Professor Waljit Dhillo and Dr Alexander Comninos.
Hormones in healthy men. Dhillo and colleagues (2005) gave six healthy men a 90-minute intravenous infusion of kisspeptin-54 and a saline infusion in random order. Kisspeptin raised LH, FSH and testosterone above saline. Mean LH over 90 minutes was 10.8 U/L on kisspeptin versus 4.2 U/L on saline. The measured plasma half-life of kisspeptin-54 was 27.6 minutes.
Brain processing in healthy men. In a 2017 study of 29 young men, kisspeptin increased activity in limbic brain regions specifically when men viewed sexual and couple-bonding images, and it reduced negative mood.
Women with low sexual desire. A randomised, double-blind crossover trial published in JAMA Network Open in 2022 enrolled 32 premenopausal women with hypoactive sexual desire disorder (HSDD). A single 75-minute kisspeptin-54 infusion changed brain activity in response to erotic videos and male faces, compared with placebo. Women with more distress about their low desire showed larger effects in some brain regions.
Men with low sexual desire. A matching trial in 32 men with HSDD, published in 2023, found greater activation of sexual brain networks and increased penile rigidity during erotic videos; the university reported rigidity up to 56% higher than on placebo.
Every one of these was a single session in a scanner or clinic, lasting hours. No trial has tested repeated doses over weeks for desire, and none has measured sexual activity at home.
Side effects reported in studies
The HSDD trials reported that kisspeptin was well tolerated with no reported side effects. The published studies are small and short, so rarer or longer-term effects would not show up. The US FDA added kisspeptin-10 to its list of substances that may raise significant safety risks in compounding in September 2023, citing possible immunogenicity for some routes and limited safety data.
Kisspeptin vs other reproductive-axis peptides
| Compound | Acts on | Human evidence |
|---|---|---|
| Kisspeptin | GnRH neurons (hypothalamus) | Small physiology and single-dose trials |
| Gonadorelin | Pituitary GnRH receptors | Approved diagnostic use in some markets |
| hCG | LH receptors on testes and ovaries | Approved medicine for fertility indications |
| PT-141 | Brain melanocortin receptors | FDA-approved for HSDD in premenopausal women |
Status in the Philippines
No kisspeptin product is registered with FDA Philippines. It is not a controlled substance under RA 9165. Local availability is through research-peptide sellers, usually as 10 mg vials of kisspeptin-10, and demand is small. Anyone interested in the reproductive-axis effects would need LH, FSH and testosterone measured to know if anything is happening; see bloodwork in the Philippines.
Storage
Lyophilised powder keeps best refrigerated and away from light. After reconstitution with bacteriostatic water, store at 2 to 8°C. During a brownout, a cooler with ice packs beats a warming fridge. See the beginner guide for handling basics.
