Hormonal

KISS1R agonist (hypothalamic neuropeptide)

Kisspeptin

Also known as: Kisspeptin-54, Kisspeptin-10, KP-54, KP-10, Metastin

Sits at the very top of the reproductive axis — triggers the cascade that produces sex hormones. Strong clinical-research evidence for hypogonadism and IVF use; off-label 'natural T' community use in healthy men runs ahead of the data.

Reviewed 2026-05-04

What it does

Kisspeptin is the natural neuropeptide that sits at the very top of the reproductive axis — it triggers the brain's release of GnRH, which drives the pituitary to release LH and FSH, which in turn drives testosterone production in men and ovarian function in women. Loss-of-function mutations in the kisspeptin receptor cause a form of hypogonadism. The clinical literature has built up over the past decade around pulsatile dosing for hypothalamic amenorrhea, oocyte maturation in IVF, exploration in hypogonadotropic hypogonadism, and characterization in normal physiology — mostly in academic-research settings rather than as an approved drug. Community off-label use of kisspeptin as a 'natural testosterone booster' in healthy men rests on a plausible upstream mechanism but no clinical-outcome data in eugonadal adults.

Used for

Dose

Starting: 1 mcg · pulsatile (e.g., every 90 minutes for hypothalamic amenorrhea)
Common: 7 mcg · pulsatile (e.g., every 90 minutes for hypothalamic amenorrhea)
Upper: 12 mcg · pulsatile (e.g., every 90 minutes for hypothalamic amenorrhea)
When: Before activityActs on the hypothalamic-pituitary-gonadal axis. Diagnostic dosing is clinic-controlled. For libido / sexual-health off-label use, 30–90 min before activity. No daily-rhythm chronopharmacology to anchor on.
Site: subcutaneous (research)

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⚠ Caution

Pregnancy (outside specific IVF research context under specialist supervision)
Hormone-sensitive malignancy (theoretical concern from sex-steroid axis stimulation)
Concurrent use with GnRH agonists/antagonists or fertility-treatment regimens without specialist supervision
Known hypersensitivity to peptide formulations

Medications & conditions

Kisspeptin with TRT — redundant/timing conflict on HPG axisUser is on testosterone replacement therapy. Kisspeptin works by stimulating endogenous LH/FSH release to drive natural testosterone production. Concurrent exogenous testosterone suppresses the same HPG axis, creating a pharmacological conflict: TRT suppresses LH while kisspeptin tries to stimulate it. This combination is most clinically relevant during TRT taper or fertility-restart protocols — use must be carefully timed and supervised.

Often stacked with

PT-141 (Bremelanotide) — Kisspeptin acts upstream (hypothalamic KISS1R → GnRH → LH/FSH → sex steroids) while PT-141 acts centrally on MC4R for direct arousal signaling — distinct axes targeting sexual function from different entry points.

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

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Use this peptide

Featured in protocols

Andropause Support — Phase 2 — HPG-axis stimulation (+Kisspeptin)
Fertility Planning — Phase 2 — Specialist-guided adjuncts (kisspeptin for women / CJC-Ipa for men preparation)

Co-injection & overlap

Inject separately (do not co-mix): PT-141 (Bremelanotide)

Reconstitution & storage

Lyophilized powder reconstituted with bacteriostatic water. Concentrations vary by vendor and active fragment (KP-54 vs KP-10) — verify per batch. Imperial-style pulsatile SubQ research dosing requires careful concentration math and a pump or programmed dosing schedule; this is not a 'set-and-forget' weekly peptide.

Storage. Lyophilized: refrigerate. Reconstituted: refrigerate 2–8 °C, use within 30 days.

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Monitoring & questions

Reported side effects

Generally well tolerated in research-clinical use
Injection-site reactions
Headache
Transient elevations in LH / FSH / sex steroids (the on-target effect)
Theoretical: induction or precipitation of ovulation in unintended contexts
OHSS risk in IVF context appears lower than with hCG triggers but is not zero
Long-term safety in non-research populations is unstudied

Biomarkers Juno tracks

FAQ (2)

Reference

How it works

Agonist at KISS1R (also known as GPR54), a Gq-coupled GPCR expressed on hypothalamic GnRH neurons. KISS1R activation drives GnRH secretion, which in turn stimulates pituitary LH and FSH release, which then drives testicular testosterone synthesis (in men) and ovarian steroidogenesis and ovulation (in women). In the IVF context, a single bolus of kisspeptin-54 has been shown to trigger oocyte maturation comparable to standard hCG triggers, with potentially lower OHSS risk. Active fragments include the full 54-residue form and the C-terminal 10-residue minimal active fragment (KP-10).

Juno's take

Kisspeptin is one of the more scientifically substantive entries here — there's a credible clinical literature on reproductive-medicine applications: hypothalamic amenorrhea, IVF ovulation triggering, hypogonadotropic hypogonadism. The same molecule can carry very different evidence weights for very different uses. The 'natural testosterone booster for healthy men' framing doesn't inherit the evidence for the medical indications — that's a different population and a different question.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Hypothalamic amenorrhea — restoration of menstrual cyclicity

Tier 2high confidence

Imperial College / Dhillo lab studies (Jayasena 2014 and follow-ups) demonstrated pulsatile kisspeptin can restore LH pulsatility and menstrual function in women with hypothalamic amenorrhea. Replicated within the same lab system, not yet at multicenter Phase 3 scale. Strong Tier 2.

Jayasena CN et al. 2014

IVF oocyte maturation trigger (alternative to hCG)

Tier 2high confidence

Multiple Phase 2 studies (Abbara, Dhillo lab) demonstrated kisspeptin-54 effectively triggers oocyte maturation in IVF cycles with potentially lower ovarian hyperstimulation syndrome (OHSS) risk than standard hCG triggers. Strong Tier 2 in this specific clinical-research context.

Abbara A et al. 2015

Hypogonadotropic hypogonadism (men) — endogenous T elevation

Tier 2medium confidence

Studies in men with hypogonadotropic hypogonadism show kisspeptin restores LH pulsatility and downstream T production. Limited to research populations; no approved clinical use.

Jayasena CN et al. 2014

Off-label 'natural testosterone booster' in eugonadal men

Tier 3high confidence

Community/clinic use as a non-suppressive alternative to TRT in healthy men rests on plausible upstream mechanism but no clinical-outcome data in eugonadal adults. The Tier 1/2 evidence in hypogonadism does NOT propagate to use in men with normal baseline T (Skill Rule 6).

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Sexual desire / arousal (independent of T elevation)

Tier 3medium confidence

Some research-context evidence that kisspeptin modulates limbic arousal circuits independent of its endocrine effects. Small-cohort fMRI / behavioral studies. Not yet a clinical indication.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (2)

[1]
Twice-daily subcutaneous injection of kisspeptin-54 does not abolish menstrual cyclicity in healthy female volunteers
Jayasena CN, Abbara A, Veldhuis JD, et al. · Journal of Clinical Investigation · 2014 · PMID 25313274
Anchor Imperial College kisspeptin clinical work supporting Tier 2 framing in reproductive-axis indications.
View source
[2]
Efficacy of kisspeptin-54 to trigger oocyte maturation in women at high risk of ovarian hyperstimulation syndrome (OHSS) during in vitro fertilization (IVF) therapy
Abbara A, Jayasena CN, Christopoulos G, et al. · Journal of Clinical Endocrinology & Metabolism · 2015 · PMID 25822128
Tier 2 anchor for the IVF oocyte-maturation indication.
View source