Carl read the papersWhat it actually is
Kisspeptin is made in the hypothalamus and tells GnRH neurons to fire. GnRH then drives LH and FSH out of the pituitary, and those drive testosterone or oestrogen. The KISS1 gene makes a 145 amino acid precursor which is cut into several lengths, including kisspeptin-54 and kisspeptin-10. They share the same active tail, so KP-10 is the short piece that still works.
This matters because of where it acts. HCG works at the testes, gonadorelin works at the pituitary, kisspeptin works one level above both of them, on the neurons that start the chain. That is the reason it keeps coming up in TRT discussions as an hCG alternative.
How it’s thought to work
- KISS1R (GPR54) agonism — Binds the kisspeptin receptor on GnRH neurons, which is one of the strongest known excitatory inputs to those cells.
- Upstream of GnRH — Drives the body's own GnRH pulse rather than replacing a downstream signal, so the pituitary still has to work.
- Pulse frequency, not just amplitude — In healthy men, a low-rate infusion of 1.5 mcg/kg/h raised LH pulse frequency from 0.7 to 1.0 pulses per hour and increased pulse size.
- Very short half-life — Terminal half-life is roughly 3 minutes for KP-10, against about 28 minutes for kisspeptin-54. Everything awkward about dosing it follows from that number.
What the research says
Better human data than most of this directory, and all of it from hospitals. In healthy men, IV boluses of 0.01 to 3.0 mcg/kg raised LH dose-dependently, with the biggest response at 1 mcg/kg: 3 mcg/kg produced a smaller rise than 1 mcg/kg. An infusion at 4 mcg/kg/h for 22.5 hours took mean LH from 5.4 to 20.8 IU/L and testosterone from 16.6 to 24.0 nmol/L in 4 men. The catch arrived early: twice-daily kisspeptin-54 for two weeks in 5 women with hypothalamic amenorrhoea produced a strong first-day response that had largely gone by day 14 (tachyphylaxis). A 2026 Imperial College study found a workaround, using subcutaneous infusions in 15 healthy men: 8 hours on and 16 hours off for 12 days kept gonadotropins up, while 5 days of continuous infusion did not, although testosterone stayed raised on the continuous schedule.
- Potent LH and FSH stimulus in men; maximal at a 1 mcg/kg IV bolus, with less effect at 3 mcg/kg.
- Sexually dimorphic: it works in men and in women near ovulation, but failed to move gonadotropins in follicular-phase women at IV doses up to 10 nmol/kg.
- Continuous exposure desensitises; intermittent exposure (8h on, 16h off) sustained the gonadotropin response for 12 days in 7 men.
- Kisspeptin-54 modulated sexual brain processing in randomised trials in men and women with low sexual desire, with penile tumescence up to 56% above placebo in the 32 men who completed that trial.
- Kisspeptin-54, not KP-10, is the form studied as an IVF trigger, where 51 of 53 women had at least one mature egg retrieved and 12 babies were born.
Reported protocols
These are the doses the peptide community actually reports running (Reddit & forums), alongside published research — logged for education, not as a recommendation to use.
| Parameter | Commonly reported range |
|---|---|
| Trial dosing (men) | A 1 mcg/kg IV bolus was the peak-response dose; the published infusions ran at 1.5 to 4 mcg/kg/h, or in nmol/h subcutaneously, all under hospital supervision. This is not a self-injection protocol |
| Community dose | 100 mcg subcutaneous is the figure that recurs on forums, reported as 3x weekly, daily, and by one poster every 2 hours; a separate poster ran 200 mcg daily on a clinic script and then dropped to 150 mcg every other day on his own initiative |
| Frequency | Pulsed, not continuous. Every schedule that held up in the literature has an off period built into the day |
| Route | Subcutaneous in community reports; the human trials used IV boluses, IV infusion or subcutaneous infusion |
| Cycle | No established cycle. The longest published chronic dosing is 12 days |
| Carl's note | The recurring community line is that more is not better, and the trials agree: 3 mcg/kg beat itself downward against 1 mcg/kg. The other recurring theme is bloodwork, because LH, FSH, testosterone and oestradiol are the only way to know anything happened. |
Common use cases
| Goal | Community protocol notes |
|---|---|
| Testicular function on TRT (reported) | the reason most people find it: an upstream alternative to hCG or gonadorelin, with no head to head trial behind that idea |
| Libido and sexual desire | the trials that showed an effect used kisspeptin-54 by infusion, not KP-10 by syringe |
| Hormone axis research | its actual job: diagnostic and mechanistic work in clinics |
Mixing it (reconstitution)
Freeze-dried peptides must be reconstituted with bacteriostatic water before they can be measured. Carl’s calculator turns “mg in the vial + ml of water + target dose” into “units on the syringe” — and tells you how long the vial lasts.
→ Open the Reconstitution Calculator
Injection & handling
Two things matter more here than technique. The first is the half-life. A subcutaneous shot is a spike, not a background level, and the published results that people quote came from controlled infusions running for hours, which a syringe at home does not reproduce. The second is that the one thing the literature is clearest about, that continuous exposure stops working, is exactly what a daily injection habit drifts toward. Reconstituted peptide belongs in the fridge, out of the light, and this acts on an endocrine axis, so bloods before and after are the only way to know anything happened. There is no approved human dose to copy, and a clinic is the right place for anything to do with the reproductive axis.
Stacks it appears in
- Instead of HCG — HCG acts at the testes, kisspeptin acts at the hypothalamus. HCG keeps working when the pituitary is fully suppressed; kisspeptin needs the chain below it to be intact.
- Instead of gonadorelin — Gonadorelin is one step down, at the pituitary. Same goal, different entry point, and gonadorelin is the one that can actually be prescribed in some places.
- Alongside TRT — The pattern it is reported in, with the same caveat as every axis compound: bloodwork, not feel.
Sources
- George JT et al. Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men. J Clin Endocrinol Metab 2011 (PMID 21632807)
- Jayasena CN et al. The effects of kisspeptin-10 on reproductive hormone release show sexual dimorphism in humans. J Clin Endocrinol Metab 2011 (PMID 21976724)
- Jayasena CN et al. Subcutaneous kisspeptin-54 in women with hypothalamic amenorrhoea: chronic administration causes tachyphylaxis. J Clin Endocrinol Metab 2009 (PMID 19820030)
- Yeung AC et al. Chronic subcutaneous kisspeptin-10 stimulates gonadotropin secretion for 12 days in healthy men. Eur J Endocrinol 2026 (PMID 42549827)
- Mills EG et al. Effects of kisspeptin on sexual brain processing and penile tumescence in men with HSDD. JAMA Netw Open 2023 (PMID 36735255)
- Thurston L et al. Effects of kisspeptin administration in women with HSDD. JAMA Netw Open 2022 (PMID 36287566)
- Sharma B et al. Use of kisspeptin to trigger oocyte maturation during IVF. Front Endocrinol 2022 (PMID 36147569, PMC9485455)
- FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (category 2 list)
- WADA 2026 Prohibited List, S2.2.1 testosterone-stimulating peptides in males
- SAHPRA registered health products register (no kisspeptin product)
- SAHPRA, Peptide Products public information page (May 2026)
- T-Nation forum thread: Kisspeptin-10, potential alternative to hCG? (2020 to 2022)
- T-Nation forum log: 200 mcg daily on a clinic script, reduced to 150 mcg every other day, with labs
