GHRP-2 Dosing & Protocols — Research Reference

GHRP-2 (pralmorelin) is a high-potency hexapeptide ghrelin-receptor agonist studied as a reference compound in growth hormone-axis research. Compared to ipamorelin, it produces a larger acute GH pulse at the cost of measurable cortisol and prolactin elevation.

Reconstitution for Research

GHRP-2 is typically supplied lyophilized in 2 mg or 5 mg vials. A 2 mL bacteriostatic-water reconstitution yields 1 mg/mL or 2.5 mg/mL. At 1 mg/mL, 10 IU on a U-100 syringe delivers 100 mcg. Refrigerate at 2–8 °C.

Reference Dose Ranges in Published Research

| Research model tier | Typical range | Notes | |---|---|---| | Entry / characterization | 100 mcg per dose | Threshold for observable GH pulse | | Standard GH-pulse studies | 100–300 mcg per dose, 2–3× daily | Most cited tier; saturation near 1 mcg/kg | | GH-stimulation test (diagnostic) | 100 mcg single dose | Published diagnostic protocol for GH-axis assessment |

Scheduling

Subcutaneous injection is the most-cited route. Three timing windows dominate the literature:

• Pre-sleep (captures nocturnal GH pulse).
• Fasted morning (avoids postprandial somatostatin/insulin blunting).
• Post-exercise (captures exercise-induced GH pulse).

Two- and three-times-daily schedules are both common; cycling typically runs 8–12 weeks on with 4-week washout to manage receptor desensitization.

Co-Administration with GHRH Analogues

GHRP-2 + a GHRH analogue (sermorelin, CJC-1295 no-DAC) produces synergistic — not additive — GH release. Typical pairing: 100–200 mcg GHRP-2 with 100–200 mcg CJC-1295 no-DAC per pulse.

Cortisol and Prolactin Considerations

Acute ACTH and prolactin elevation 30–60 minutes after dosing is well-documented and dose-dependent. Researchers studying HPA-axis-naive GH release should choose ipamorelin instead.

Quality and Identity Verification

LC-MS confirmation of molecular weight (817.99 Da) and HPLC purity ≥98% are the standard acceptance criteria.

Research Use Only. All content is for laboratory research and educational reference. Compounds discussed are not intended for human or veterinary consumption.

References

1. Bowers CY. GH releasing peptides — structure and kinetics. J Pediatr Endocrinol. 1993;6(1):21–31.
2. Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev. 2018;6(1):45–53.
3. Pihoker C, Kearns GL, French D, Bowers CY. Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2. J Clin Endocrinol Metab. 1998;83(2):402–406.