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phase 2Sexual Health

Kisspeptin-54

Also known as: Metastin, KP-54, KISS1, Full-Length Kisspeptin

Kisspeptin-54 is the full-length endogenous neuropeptide encoded by the KISS1 gene, functioning as the master upstream regulator of the reproductive hormonal axis. Discovered through its role in suppressing cancer metastasis (hence the name "metastin"), kisspeptin-54 was subsequently identified as the critical signal that triggers GnRH release from the hypothalamus, controlling puberty onset, fertility, and reproductive function. Currently in Phase 2 clinical trials, kisspeptin-54 is being investigated as a novel fertility treatment for triggering oocyte maturation in IVF with a potentially safer profile than hCG, as well as a diagnostic tool for reproductive disorders and a potential therapy for hypogonadism.

4 cited references·5 researched benefits

Quick Answer

Kisspeptin-54 (metastin) is a 54-amino acid neuropeptide that serves as the master regulator of reproductive hormone release by stimulating GnRH neurons in the hypothalamus. In Phase 2 clinical trials for IVF, it triggers oocyte maturation with a significantly lower risk of ovarian hyperstimulation syndrome compared to hCG. It is also being studied as a diagnostic tool for reproductive disorders and as a potential therapy for hypothalamic amenorrhea.

Key Facts

Mechanism
Kisspeptin-54 binds to the KISS1R receptor (also known as GPR54) expressed on GnRH neurons in the hypothalamus, particularly in the arcuate nucleus and anteroventral periventricular nucleus (AVPV). This activation triggers robust GnRH release into the hypothalamic-hypophyseal portal system, which in turn stimulates LH and FSH secretion from the anterior pituitary. Kisspeptin-54 is the primary gatekeeper of puberty onset and the pulsatile GnRH secretion pattern that maintains fertility. Unlike GnRH agonists, kisspeptin acts upstream of GnRH neurons, producing a more physiologic activation pattern. In cancer biology, kisspeptin-54 was originally identified as a metastasis suppressor that inhibits tumor cell migration and invasion through KISS1R-mediated signaling.
Research Status
phase 2
Half-Life
~28 minutes
Molecular Formula
C₂₉₅H₄₆₂N₈₆O₈₅S₃
Primary Use
Sexual Health
Table of Contents

Benefits

  • Triggers oocyte maturation in IVF with dramatically lower risk of ovarian hyperstimulation syndrome (OHSS) compared to hCG — Phase 2 data show near-elimination of OHSSmoderate
  • Stimulates endogenous gonadotropin release in a more physiologic pattern than exogenous GnRH — potent LH surge without prolonged receptor desensitizationmoderate
  • Diagnostic utility for reproductive disorders — kisspeptin challenge test can distinguish between hypothalamic and pituitary causes of hypogonadismmoderate
  • Restores reproductive hormone pulsatility in hypothalamic amenorrhea — preliminary studies show recovery of LH pulses in women with functional amenorrheapreliminary
  • Original metastasis-suppressor properties — KISS1/kisspeptin signaling inhibits tumor cell migration, invasion, and metastasis in multiple cancer modelspreliminary

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intravenous bolus (IVF oocyte maturation trigger)1.6-12.8 nmol/kgSingle dose at time of trigger (when follicles reach 17-18 mm)Investigational. Phase 2 trial doses typically 9.6 nmol/kg IV. Produces a more physiologic LH surge compared to hCG trigger.
Subcutaneous injection (research)0.3-1.0 nmol/kgSingle or repeated doses in clinical studiesInvestigational. Used in research protocols to study reproductive neuroendocrine function and kisspeptin responsiveness.
Intravenous infusion (diagnostic)1.0 nmol/kg/hourSingle infusion over 60-90 minutesInvestigational diagnostic use. LH response measured at serial intervals to assess HPG axis integrity. More physiologic than standard GnRH stimulation test.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Facial flushing and warmth — the most commonly reported side effect, typically mild and transientcommon
  • Mild abdominal discomfort — reported in some clinical trial participants, usually self-limitingcommon
  • Injection site reactions — mild pain and redness at subcutaneous or intravenous injection sitescommon
  • Dizziness and lightheadedness — transient postural symptoms in some subjects following intravenous administrationrare
  • Headache — reported in a small percentage of trial participantscommon

Frequently Asked Questions

What is the difference between kisspeptin-54 and kisspeptin-10?
Kisspeptin-54 is the full-length 54-amino acid peptide produced by cleavage of the KISS1 precursor protein, while kisspeptin-10 is the minimal C-terminal fragment (amino acids 45-54) that retains full receptor binding activity. Both activate the KISS1R receptor, but they have different pharmacokinetic profiles: kisspeptin-54 has a longer half-life (~28 minutes vs. ~4 minutes for kisspeptin-10) and produces a more sustained LH response. Kisspeptin-54 is being developed for IVF applications, while kisspeptin-10 is used more in research settings due to its shorter duration of action.
How could kisspeptin-54 replace hCG as an IVF trigger?
In IVF, an hCG injection is traditionally used to trigger final oocyte maturation before egg retrieval. However, hCG has a long half-life (~36 hours) and can cause ovarian hyperstimulation syndrome (OHSS), a potentially life-threatening condition. Kisspeptin-54 triggers a natural LH surge through the endogenous hypothalamic pathway, and because its half-life is only 28 minutes, the resulting LH elevation is shorter and more physiologic. Phase 2 trials by Professor Waljit Dhillo at Imperial College London have shown that kisspeptin-54 can successfully trigger oocyte maturation while nearly eliminating OHSS risk.
Why was kisspeptin originally called metastin?
The KISS1 gene was discovered in 1996 at the Pennsylvania State University (in Hershey, PA — hence "KISS" from "Hershey's Kisses") as a metastasis-suppressor gene. The protein product was named "metastin" because it suppressed cancer cell metastasis without affecting primary tumor growth. It was not until 2003 that two independent research groups discovered that mutations in the kisspeptin receptor (KISS1R/GPR54) cause hypogonadotropic hypogonadism, revealing kisspeptin's critical role in reproduction. This unexpected connection between cancer biology and reproductive endocrinology opened an entirely new field of research.
Is kisspeptin-54 available as a treatment today?
Kisspeptin-54 is not yet approved for clinical use. It is currently in Phase 2 clinical trials, primarily at Imperial College London, for IVF oocyte maturation triggering and reproductive disorder diagnosis. Research-grade kisspeptin-54 is available from peptide synthesis companies, but it is not available from pharmacies or compounding pharmacies for clinical use. If trials continue to show positive results, it could reach Phase 3 trials and eventual regulatory approval, potentially transforming IVF safety. Current estimates suggest regulatory approval could be several years away.
Can kisspeptin-54 treat low testosterone in men?
Preliminary research shows that kisspeptin-54 administration robustly stimulates LH and testosterone release in men, including those with functional hypogonadism. However, its short half-life means that a single injection produces only a temporary testosterone rise. Sustained kisspeptin therapy (through infusions or longer-acting analogs) could potentially restore endogenous testosterone production by stimulating the natural HPG axis rather than replacing hormones exogenously. This is an active area of investigation, with the theoretical advantage of preserving fertility — unlike testosterone replacement therapy, which suppresses spermatogenesis.

References

  1. 1
    GPR54 mutations in hypogonadotropic hypogonadism reveal kisspeptin as a gatekeeper of puberty(2003)PubMed ↗
  2. 2
    Kisspeptin-54 triggers egg maturation in women undergoing in vitro fertilization(2014)PubMed ↗
  3. 3
    Kisspeptin and the control of gonadotropin secretion in humans(2012)PubMed ↗
  4. 4
    KISS1 and KISS1R as novel therapeutic targets in reproductive and cancer biology(2009)PubMed ↗

Latest Research

Last updated: 2026-02-19