Educational reference, not medical advice. This page summarizes information from published research and regulatory filings for educational purposes. It is not a recommendation to use any compound and should not replace guidance from a licensed healthcare provider. Most peptides discussed here are not approved for the uses described.
What it is
Kisspeptin-10 (Kp-10) is the C-terminal decapeptide of the kisspeptin family — the smallest naturally occurring fragment that retains full activity at the kisspeptin receptor KISS1R (also called GPR54). The longer 54-amino-acid form (kisspeptin-54) is the main circulating species; kisspeptin-10 is what most published clinical infusions and research peptide vials contain because it is easier to synthesize and stable enough for short-term use.
The peptides are products of the KISS1 gene, originally identified for an entirely different reason: suppression of cancer metastasis.
History
The KISS1 gene was cloned in 1996 by Danny Welch's lab at Penn State Hershey Medical Center as a metastasis-suppressor gene in melanoma — the name "KISS" is a reference to Hershey Chocolate Kisses, where the lab was based. For several years it was studied primarily in cancer biology.
In 2003, two independent groups (one led by Stéphanie Seminara at Massachusetts General Hospital and one led by Nicolas de Roux in France) identified mutations in the kisspeptin receptor as a cause of normosmic hypogonadotropic hypogonadism — establishing kisspeptin signaling as essential for GnRH neuron activation and reproductive function. The "two lives" of kisspeptin — metastasis suppressor and reproductive switch — emerged as one of the more unusual stories in modern endocrinology.
Translational human research has been centered at Imperial College London under Waljit Dhillo. The group has run a series of trials of kisspeptin infusion in healthy volunteers, in women with hypothalamic amenorrhea, and in men and women with HSDD. The 2023 JAMA Network Open trial in men with HSDD reported increased brain activity in response to sexual stimuli and a small increase in penile tumescence under kisspeptin compared with placebo.
Regulatory status
Kisspeptin-10 is not approved by any regulator. It is investigational. No registered Phase 3 trial supports a current marketing application. The Imperial College program continues under research authorization in the United Kingdom; in the United States, kisspeptin is not on the FDA 503A bulk substances list and compounding pharmacies cannot legally prepare it for patients.
Mechanism
Kisspeptin neurons in the hypothalamus — concentrated in the arcuate nucleus and the anteroventral periventricular nucleus — sit upstream of GnRH neurons and act as the principal integrators of sex steroid feedback, metabolic state, and stress input on the reproductive axis. Kisspeptin binding to KISS1R on GnRH neurons triggers GnRH release, which in turn drives luteinizing hormone and follicle-stimulating hormone secretion from the pituitary.
The Imperial College sexual-desire work proposes a complementary central action: published fMRI studies show that kisspeptin infusion enhances limbic responses to sexual cues and modulates default-mode network connectivity in ways correlated with self-reported sexual desire. This is a different proposed mechanism from peripheral hormone effects.
Half-life and dosing intervals
Kisspeptin-10 has a very short circulating half-life — published estimates are roughly 4 minutes after intravenous bolus. Most clinical work has used continuous intravenous infusion rather than subcutaneous bolus dosing precisely because of the rapid clearance.
Imperial College trials have typically used intravenous infusions of 1 to 10 nmol/kg/hour for periods ranging from 75 minutes to several hours. Subcutaneous use described in observational research peptide protocols is not directly supported by published pharmacokinetic data; doses commonly described online (50 to 500 mcg per injection) are extrapolations.
Reconstitution example
Kisspeptin-10 is supplied lyophilized in 1 mg or 5 mg vials. A 1 mg vial reconstituted with 2 mL of bacteriostatic water yields 500 mcg/mL. On a 1 mL U-100 insulin syringe, 20 units (0.2 mL) delivers 100 mcg. Vial's calculator handles the conversion when vial mass and water volume are entered.
What to know
- Investigational only. Not approved by any regulator. All controlled human data comes from Imperial College London and a few related academic centers.
- Very short half-life. The published pharmacokinetic profile favors infusion over bolus injection. Subcutaneous bolus dosing has not been characterized in controlled trials.
- Two distinct biologies. Kisspeptin is both a metastasis suppressor and the upstream regulator of GnRH. Most clinical interest has been in the reproductive axis.
- Storage. Lyophilized: refrigerate, protect from light. Reconstituted: refrigerate and use within 1 to 2 weeks; the very short native half-life corresponds to fragile peptide chemistry in solution.
- Safety profile is incomplete. Imperial College infusion studies have reported good short-term tolerability in healthy volunteers, but no long-term subcutaneous safety data exists.
- Three forms in circulation. Kisspeptin-10 (Kp-10), kisspeptin-54 (Kp-54), and the parent prepro-kisspeptin are all called "kisspeptin" in popular usage. Most published clinical work uses Kp-54; most research peptide vials contain Kp-10.
Sources
- 1.Lee JH et al. (1996). KiSS-1, a novel human malignant melanoma metastasis-suppressor gene. Journal of the National Cancer Institute.
- 2.Comninos AN et al. (2017). Kisspeptin modulates sexual and emotional brain processing in humans. Journal of Clinical Investigation.
- 3.Mills EG et al. (2023). Effects of Kisspeptin on Sexual Brain Processing and Penile Tumescence in Men With Hypoactive Sexual Desire Disorder: A Randomized Clinical Trial. JAMA Network Open.
- 4.Comninos AN et al. (2018). Modulations of human resting brain connectivity by kisspeptin enhance sexual and emotional functions. JCI Insight.