Side-by-side · Research reference

HexarelinvsKisspeptin-10

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

APhase 1HUMAN-REVIEWED19/45 cited

BPhase 2HUMAN-REVIEWED10/41 cited

Hexarelin

Hexapeptide GHRP · Cardio-tropic

100–200 mcgPer doseSmith 1996

Phase 1Evidence levelGhigo 1997

~70 minHalf-lifeSemenistaya 2010

SQ · Multiple sites · 1–3×/day

Kisspeptin-10

Neuropeptide · GPR54 Agonist

GnRH pulse generatorPrimary roleSilva 2026

Phase 1/2Clinical stage

GPR54/Kiss1RTarget receptorRønnekleiv 2026

IV / SQ · Investigational

01Mechanism of Action

Parameter

Hexarelin

Kisspeptin-10

Primary target

Ghrelin receptor (GHS-R1a) + cardiac CD36Smith 1996 Ghigo 1997

GPR54/Kiss1R on hypothalamic GnRH neuronsRønnekleiv 2026 Collado-Sole 2026

Pathway

GHS-R1a → Gαq → Ca²⁺ → GH release. CD36 engagement → direct cardio-tropic actionGhigo 1997

Kisspeptin → GPR54 activation → GnRH neuronal depolarization → Pulsatile GnRH release → Pituitary LH/FSH secretionLages 2026 Rønnekleiv 2026

Downstream effect

Strong GH pulse + IGF-1 elevation; cardio-protective effects in animal MI modelsGhigo 1997

Pulsatile LH surge, FSH elevation, gonadal steroidogenesis, gametogenesis initiationLages 2026

Feedback intact?

Yes initially; tachyphylaxis with chronic useGhigo 1997

Yes — integrates estradiol, leptin, and IGF-1 signals to modulate HPG axisSilva 2026 Rønnekleiv 2026

Origin

Synthetic hexapeptide His-D-2-Methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂Smith 1996

C-terminal decapeptide of KISS1 gene product; retains full biological activity of longer kisspeptin isoforms

Antibody development

—

02Dosage Protocols

Parameter

Hexarelin

Kisspeptin-10

Standard dose

100–200 mcg per injectionSmith 1996

—

Frequency

1–2× per day max (tachyphylaxis with chronic 3× daily)

—

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 1 / Phase 2 trialsSmith 1996 Ghigo 1997

Phase 1/2 trials

Duration

4–8 weeks on / 4–8 weeks off (tachyphylaxis mitigation)

—

Reconstitution

Bacteriostatic water

—

Timing

Pre-sleep + fasted preferred

—

Half-life

~70 minSemenistaya 2010

Short (minutes)

Rapid clearance; pulsatile dosing mimics physiological GnRH pulse frequency.

Clinical trial dose

—

Phase 1/2 investigational

Dosing protocols vary by indication (hypothalamic amenorrhea, IVF trigger).

Route

—

IV or SQ administration

IV preferred in controlled trials for precise pulsatile delivery.

04Side Effects & Safety

Parameter

Hexarelin

Kisspeptin-10

Cortisol elevation

Modest at high dosesGhigo 1997

—

Prolactin elevation

Modest at high dosesGhigo 1997

—

Hunger

Strong appetite increase via ghrelin agonism

—

Tachyphylaxis

Receptor desensitisation with chronic dosingGhigo 1997

—

Cardiac effects

Direct cardio-tropic; potential benefit in MI but unstudied in humansGhigo 1997

—

IGF-1 elevation

Strong; monitor with chronic high-dose use

—

Cancer risk

Contraindicated in active malignancy (GH/IGF-1 axis)

—

Pregnancy / OB

Avoid

—

Ovarian hyperstimulation

—

Theoretical risk with supraphysiological dosing in fertility protocols

Headache

—

Mild, reported in early-phase trials

Nausea

—

Transient GI symptoms with IV bolus

Hot flashes

—

Vasomotor symptoms from LH surge

Injection site reaction

—

Erythema, mild discomfort (SQ route)

Absolute Contraindications

Hexarelin

·Active malignancy
·Pregnancy / breastfeeding
·Disrupted hypothalamic-pituitary axis

Kisspeptin-10

·Active pregnancy
·Hormone-sensitive malignancy (breast, ovarian, endometrial)

Relative Contraindications

Hexarelin

·Untreated diabetes
·Severe hyperprolactinemia

Kisspeptin-10

·Polycystic ovary syndrome (PCOS) without monitoring
·Uncontrolled thyroid dysfunction

05Administration Protocol

Parameter

Hexarelin

Kisspeptin-10

1. Reconstitution

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.

Reconstitute with sterile water or saline per protocol. Gently swirl — do not shake. Solution should be clear and colorless.

2. Injection site

SQ — abdomen or thigh. Rotate sites.

IV infusion for pulsatile delivery in clinical trials; SQ for outpatient protocols. IV allows precise temporal control of GnRH pulse frequency.

3. Timing

Pre-sleep + fasted preferred. Cycle on/off to avoid tachyphylaxis.

Pulsatile dosing (e.g., every 60–90 min) mimics physiological GnRH pulse generator. Single-bolus protocols used for LH surge induction in fertility research.

4. Storage

Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.

Serial LH, FSH, estradiol measurements to confirm HPG axis activation. Ultrasound monitoring for ovarian response in fertility applications.

5. Needle

29–31G, 4–8 mm insulin syringe.

Lyophilized: store at 2–8 °C, light-protected. Reconstituted: refrigerate, use within 24–48 hours per protocol.

06Stack Synergy

Hexarelin

+ CJC-1295 (no DAC)

Strong

View CJC-1295 (no DAC) →

Hexarelin (GHRP) + CJC-1295-no-DAC (GHRH analogue) is the higher-amplitude variant of the standard GHRH+GHRP stack. Hexarelin produces a stronger pulse than ipamorelin but with cortisol + prolactin signal — choose this stack for maximum GH amplitude when side-effect tolerance is acceptable. Cycle aggressively.

Hexarelin: 100 mcg SQ · pre-sleep
CJC-1295 (no DAC): 100 mcg SQ · same injection
Primary benefit: Maximum GH pulse amplitude (with side-effect signal)

Smith 1996 Teichman 2006

Kisspeptin-10

— no documented stacks