Complete dosing reference for the three main GHRP analogues — Ipamorelin, GHRP-2, and GHRP-6. Includes side-by-side comparison, timing windows, reconstitution protocol, and GHRH stacking guidance.
GHRP (pentapeptide) · Half-life: ~2 hours
100–300 mcg
1–3× daily
Best for: Beginners, fat loss, sleep quality, lean mass
GHRP (hexapeptide) · Half-life: ~30 minutes
100–300 mcg
2–3× daily
Best for: Maximum GH output, aggressive body composition
GHRP (hexapeptide) · Half-life: ~15–60 minutes
100–300 mcg
2–3× daily
Best for: Caloric surplus, muscle growth, appetite stimulation
| Property | Ipamorelin | GHRP-2 | GHRP-6 |
|---|---|---|---|
| Standard Dose | 100–300 mcg | 100–300 mcg | 100–300 mcg |
| Frequency | 1–3× daily | 2–3× daily | 2–3× daily |
| Half-Life | ~2 hours | ~30 min | ~15–60 min |
| GH Amplitude | Moderate | High | High |
| Cortisol Effect | Minimal | Moderate | Moderate–High |
| Prolactin Effect | Minimal | Moderate | Moderate |
| Appetite Effect | Minimal | Moderate | High (significant) |
| Selectivity | High (GHS-R1a only) | Moderate (GHS-R1a + CD36) | Low (GHS-R1a + ghrelin) |
| Best Stack Partner | Any GHRH analogue | CJC-1295 (no DAC) | CJC-1295 (no DAC) |
| Best Use Case | Beginners, fat loss, sleep | Max GH, body composition | Bulking, appetite stimulation |
GHRPs produce their greatest effect when combined with a GHRH analogue (Sermorelin, CJC-1295, or Tesamorelin). The two peptide families act on different receptors — GHS-R1a (GHRPs) and GHRH-R (GHRH analogues) — and their signaling cascades summate to produce 3–5× greater GH output than either alone. Inject both compounds simultaneously as a single subcutaneous injection in a fasted state.
Step-by-Step Reconstitution
Gather supplies
Lyophilized GHRP vial, bacteriostatic water (BW), 1 mL syringe, alcohol swabs, insulin syringe for injection.
Clean vial tops
Wipe the rubber stopper of both the GHRP vial and the BW vial with an alcohol swab. Allow to air dry.
Draw bacteriostatic water
Draw 1–2 mL of bacteriostatic water into the syringe. For a 5 mg vial, 2 mL BW gives 250 mcg per 0.1 mL (10 units on U-100 syringe).
Inject BW into peptide vial
Insert the needle at an angle and inject BW slowly along the side wall of the vial — do not inject directly onto the powder. This prevents denaturation.
Dissolve gently
Gently swirl or roll the vial between your palms until the powder is fully dissolved. Do not shake — this can damage the peptide.
Store correctly
Store reconstituted GHRP at 2–8°C (refrigerator). Use within 28–30 days. Lyophilized (unreconstituted) peptide can be stored at -20°C for up to 24 months.
Quick dosage reference (5 mg vial + 2 mL BW): Each 0.1 mL = 250 mcg. For 100 mcg: draw 0.04 mL (4 units). For 200 mcg: draw 0.08 mL (8 units). For 300 mcg: draw 0.12 mL (12 units).
Safety Considerations
• Cortisol monitoring: GHRP-2 and GHRP-6 produce moderate cortisol stimulation. Long-term use without cycling may elevate baseline cortisol. Ipamorelin does not share this concern.
• Blood glucose: GH elevation transiently reduces insulin sensitivity. Individuals with pre-diabetes or metabolic syndrome should monitor fasting glucose.
• Water retention: GH-mediated sodium retention can cause mild edema, particularly at higher doses or during the first 2–4 weeks of a new protocol.
• Cycling: Most GHRP protocols run 8–12 weeks followed by a 4-week break to prevent GHS-R1a desensitization.
• Not for human use: All GHRPs discussed are research compounds, not FDA-approved for human administration.
What is the standard dosage for GHRP peptides?
Dosing varies by compound. Ipamorelin is typically dosed at 100–300 mcg per injection, 1–3× daily. GHRP-2 is dosed at 100–300 mcg per injection, 2–3× daily. GHRP-6 is dosed at 100–300 mcg per injection, 2–3× daily. All GHRPs are most effective when injected in a fasted state (2–3 hours post-meal) to avoid insulin-mediated suppression of GH release.
Which GHRP produces the highest GH release?
GHRP-2 consistently produces the highest GH amplitude of the three main GHRPs in head-to-head studies, followed by GHRP-6, then Ipamorelin. However, Ipamorelin is the most selective — it produces minimal cortisol, prolactin, or appetite stimulation compared to GHRP-2 and GHRP-6. For most researchers, Ipamorelin's selectivity makes it the preferred GHRP despite its lower peak GH output.
Should GHRPs be stacked with a GHRH analogue?
Yes — combining a GHRP with a GHRH analogue (Sermorelin, CJC-1295, or Tesamorelin) produces synergistic GH amplification of 3–5× compared to either alone. The two peptide families act on different receptors (GHS-R1a for GHRPs vs. GHRH-R for GHRH analogues), and their intracellular signaling cascades converge additively on GH secretion. The CJC-1295 + Ipamorelin stack is the most widely studied combination.
What is the best time to inject GHRP peptides?
The pre-sleep injection is the most important window for all GHRPs, as it amplifies the natural nocturnal GH pulse. Additional effective windows include fasted morning (maximizes GH pulse amplitude) and 30–45 minutes pre-workout (amplifies exercise-induced GH release). Avoid injecting within 2 hours of a carbohydrate-rich meal, as elevated insulin blunts the GH response.
Does GHRP-6 really cause significant hunger?
Yes — GHRP-6 produces the most significant appetite stimulation of the three GHRPs due to its activity at both GHS-R1a and ghrelin receptors. Many researchers report intense hunger within 20–30 minutes of injection. This can be advantageous for those in a caloric surplus (bulking), but problematic for fat loss protocols. Ipamorelin and GHRP-2 produce substantially less appetite stimulation.
How do you reconstitute GHRP peptides?
All GHRPs follow the same reconstitution process: add 1–2 mL of bacteriostatic water to the lyophilized vial, injecting slowly along the side wall (not directly onto the powder). Gently swirl — do not shake. Store reconstituted peptide at 2–8°C and use within 28–30 days. For a 5 mg vial reconstituted with 2 mL, each 0.1 mL (10 units on a U-100 insulin syringe) equals 250 mcg.
Research-Grade Compounds
Purgo Labs offers Ipamorelin and GHRP blends with third-party COA verification and independent purity testing.
Shop Purgo Labs — Use Code HEALTH (15% Off)Research Purposes Only. All dosage information is for educational purposes. GHRP peptides are not FDA-approved for human use. Nothing on this page constitutes medical advice. Consult a qualified healthcare provider before considering any peptide protocol.
Medical Disclaimer: All content on this site is for educational and research purposes only. Research peptides are not FDA-approved for human use. Always consult a qualified healthcare professional before considering any peptide or supplement protocol. Nothing on this site constitutes medical advice, diagnosis, or treatment.