Kisspeptin: the basics
What is it?
A natural hormone made in the brain that acts like a master switch for puberty and fertility by telling the brain to release GnRH.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗What do people claim it helps with?
Boosting testosterone, libido or fertility, and improving IVF outcomes. Only the IVF use has been studied in proper clinical trials.
What has research actually shown?
Small studies at one London IVF clinic found an injection of kisspeptin-54 could trigger egg maturation, including in women at high risk of a dangerous over-response to fertility drugs.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗Has this been demonstrated in people?
Small phase 2 human trials and short hormone studies, plus laboratory and animal research. No large trial has compared it with the usual IVF triggers.
Research paper 1 ↗Research paper 2 ↗Research paper 3 ↗What side effects, risks and unknowns should I understand?
Studies were short and supervised, so long-term safety is unknown. FDA lists kisspeptin-10 as a compounding substance with possible immune-reaction and impurity risks.
FDA safety information ↗Is it an approved medicine?
No FDA-approved medicine contains kisspeptin. It is an investigational hormone, and FDA has placed kisspeptin-10 on its compounding safety-risk list.
FDA safety information 1 ↗FDA briefing 2 ↗Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.
How is it used or studied?
Studied as an injection or, in one study, a nasal spray, using research preparations in clinics. There is no approved product.
Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.
A common misunderstanding
Kisspeptin-10 and kisspeptin-54 are different lengths of the same hormone family; most IVF studies used kisspeptin-54, not the kisspeptin-10 sold online.
What should I ask a clinician?
- What diagnosis or goal are we trying to address, and what established options are available?
- Was the expected benefit shown in people like me, using this exact product?
- How could my medicines, health conditions or pregnancy plans affect the risks?
- What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
- Peptide
- A short chain of amino acids, the building blocks of proteins.
- Preclinical
- Research in cells, tissues or animals before dependable treatment evidence in people.
- Controlled trial
- A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
- Biomarker
- A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
Kisspeptin Evidence & Clinical Profile
Human Study Limits
Kisspeptin has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.
Laboratory & In Vivo Assays
Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.
What is Kisspeptin?
Kisspeptin (kisspeptin-10, kisspeptin-54) is A family of natural peptides, made from the KISS1 gene, that switch on the brain's reproductive hormone system by triggering GnRH release. People with faulty kisspeptin signalling do not go through normal puberty. Small phase 2 studies at one London IVF unit used kisspeptin-54 to trigger egg maturation, but no kisspeptin product is approved, and kisspeptin-10 is on FDA's list of compounding substances with significant safety risks. Aliases include: Kisspeptin-10, Kisspeptin-54, Metastin, KP-10, KISS1-derived peptides.
- Sequence (one-letter)
- YNWNSFGLRF-NH2
- Molecular formula
- C63H83N17O14
- Molecular weight
- 1302.4 g/mol
- CAS Number
- 374675-21-5
- UNII Code
- FS1N52VS3S
- PubChem CID
- 25240297
Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ · PubChem record ↗ See all names and codes in the peptide name index.
Clinical Trials & Human Cohorts
Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.
Kisspeptin-54 triggers egg maturation in women undergoing in vitro fertilization [1]
What was reported
A single kisspeptin-54 injection produced mature eggs; embryos were transferred in 92% of women and the clinical pregnancy rate was 23%.
What limits the conclusion
No comparison with standard triggers such as hCG; single centre; small dose groups.
Efficacy of Kisspeptin-54 to Trigger Oocyte Maturation in Women at High Risk of Ovarian Hyperstimulation Syndrome (OHSS) During In Vitro Fertilization (IVF) Therapy [2]
What was reported
Egg maturation occurred in 95% of women, and no woman developed moderate, severe or critical OHSS.
What limits the conclusion
Open-label, no hCG or GnRH-agonist comparison group, one IVF unit.
A second dose of kisspeptin-54 improves oocyte maturation in women at high risk of ovarian hyperstimulation syndrome: a Phase 2 randomized controlled trial [3]
What was reported
A second kisspeptin-54 injection raised the share of women reaching the target egg yield from 45% to 71%.
What limits the conclusion
Single centre; the authors state that direct comparisons with established triggers are still needed.
How the compound may work
Mechanisms describe how Kisspeptin may affect biological processes. Laboratory findings and patient outcomes answer different questions.
KISS1R (GPR54) activation
Kisspeptins encoded by the KISS1 gene were identified as the natural ligands of the receptor GPR54, now called KISS1R. [5]
Required for normal puberty
Members of a family with a loss-of-function mutation in GPR54 had hypogonadotropic hypogonadism, showing the receptor is needed for the reproductive hormone axis in people. [6]
GnRH and LH release
Kisspeptin acts at the hypothalamus to release the body's own GnRH, which then raises luteinizing hormone (LH); this LH surge is what the IVF studies use to mature eggs. [3]
Areas Being Studied
These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.
IVF egg-maturation trigger
Tested as a gentler trigger for women at high risk of ovarian hyperstimulation syndrome. [2]
Hypothalamic amenorrhoea and nasal delivery
A nasal spray raised LH in healthy volunteers and women with hypothalamic amenorrhoea in a short-term study. [4]
Reproductive physiology
Kisspeptin and neurokinin B signalling are studied in puberty, fertility and menopause biology. [7]
Compare the study designs.
| Study | Design / sample | Outcome type | Key limitation |
|---|---|---|---|
| First IVF trigger study · 2014 [1] | Phase 2 dose-ranging clinical study n = 53 |
Clinical endpoint evaluation | No comparison with standard triggers such as hCG; single centre; small dose groups. |
| Women at high OHSS risk · 2015 [2] | Phase 2 open-label randomized dose-finding trial n = 60 |
Clinical endpoint evaluation | Open-label, no hCG or GnRH-agonist comparison group, one IVF unit. |
| Second-dose trial · 2017 [3] | Phase 2 randomized placebo-controlled trial n = 62 |
Clinical endpoint evaluation | Single centre; the authors state that direct comparisons with established triggers are still needed. |
Regulatory Status & Clinical Safety
Regulatory Classification
Not FDA approved; no U.S. medicine contains kisspeptin. Kisspeptin-10 is in FDA's 503A bulk-substance category 2 (significant safety risks, added September 29, 2023). WADA's 2026 Prohibited List names kisspeptin and its agonist analogues under S2.2.1 (testosterone-stimulating peptides in males), prohibited at all times.
Safety Realities & Impurities
Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.
Clinical Trials Registry Records
Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.
The Use of the Hormone Kisspeptin in 'in Vitro Fertilisation' (IVF) Treatment [8]
- Planned enrollment
- 175 (patients)
- Posted results
- Available
- Sponsor
- Imperial College London
- Last updated
- 2021
Reproductive Hormones During Sustained Administration of Kisspeptin [9]
- Planned enrollment
- 76 (patients)
- Posted results
- Pending in registry
- Sponsor
- Imperial College London
- Last updated
- 2024
WADA & Anti-Doping Regulations
WADA Section S2: Prohibited Substance
The World Anti-Doping Agency (WADA) classifies Kisspeptin under Section S2 of the Prohibited List. Prohibited at all times (in- and out-of-competition). Last verified: October 2026.
Research Timeline
-
2001
Receptor ligand identified
Kisspeptins from the KISS1 gene are shown to be the natural ligands of GPR54. [5]
-
2003
Human puberty link
GPR54 loss-of-function is found to cause hypogonadotropic hypogonadism. [6]
-
2014
First IVF use
Kisspeptin-54 triggers egg maturation in women undergoing IVF. [1]
-
2023
FDA compounding category 2
FDA places kisspeptin-10 in 503A category 2 for potential immunogenicity, impurity and characterization concerns. [10]
-
2025
Nasal spray study
Intranasal kisspeptin raises reproductive hormones in a randomized crossover study. [4]
What Researchers Still Don't Know
Long-term safety profiles
Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.
Optimal dose-response thresholds
Comparative trials optimizing minimal effective exposure versus adverse event rates.
Formulation bioavailability
Differences between oral, subcutaneous, and modified peptide delivery vehicles.
References
Primary sources verified against PubMed / NLM and regulatory databases.
- Clinical study
- Phase 2 RCT
- Phase 2 RCT
- Randomized crossover study
- Laboratory study
- Human genetics study
-
Review
Kisspeptin and neurokinin B: roles in reproductive health ↗ (external website)
- Registry Record
-
Registry Record
NCT02081924 Reproductive Hormones During Sustained Administration of Kisspeptin ↗ (external website)
- FDA compounding safety page