GHRP-2 (Pralmorelin / KP-102)

GHRP-2 (Growth Hormone Releasing Peptide-2) is a synthetic hexapeptide with the sequence D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2. Its CAS number is 158861-67-7, and its molecular weight is 817.97 Da. It's the most potent GHRP for acute GH stimulation, but that potency comes with baggage. Unlike ipamorelin (which cleanly releases GH with almost no cortisol or prolactin effects), GHRP-2 raises cortisol by 25-35% and prolactin by 15-25% within 30 minutes of injection. Both return to baseline in 2-3 hours, but the elevation matters for people on long-term protocols. The appetite effect is real and measurable. Reiter et al. published a controlled study in the Journal of Clinical Endocrinology and Metabolism (2005, PMID: 15699539) showing that GHRP-2 infusion increased food intake by 35.9% in healthy men. This is less than GHRP-6 (which causes intense hunger) but more than ipamorelin (which barely affects appetite). For people trying to gain weight during recovery from illness or cachexia, the appetite boost is a feature. For people cutting, it's a problem. The synergy with GHRH analogs is where GHRP-2 gets interesting. GHRPs and GHRH work through completely different signaling pathways (Gq/11 versus cAMP). When you combine them, the GH output isn't additive, it's multiplicative. One study measured a 54-fold increase in pulsatile GH secretion with GHRP + GHRH versus baseline. This is why the classic peptide stack pairs a GHRP (like GHRP-2) with a GHRH analog (like CJC-1295 or sermorelin). In Japan, GHRP-2 is approved as a diagnostic agent for growth hormone deficiency under the brand name marketed by Kaken Pharmaceutical. A GH response below 9 ng/mL indicates adult GHD, and below 16 ng/mL indicates pediatric GHD. The regulatory situation in the US is not favorable. GHRP-2 was placed on the FDA Category 2 restricted list, and it was specifically excluded from the 14 peptides returning to Category 1 under the February 2026 HHS announcement. The cortisol and prolactin elevation were cited as safety concerns. Ipamorelin, which has none of these issues, was included in the Category 1 return. This regulatory gap has made ipamorelin the preferred clinical GHRP for most practitioners. The standard subcutaneous dose is 100-300 mcg per injection, 1-3 times daily on an empty stomach. Above about 200 mcg per injection, you hit diminishing returns on GH release while side effects continue to increase. Most protocols dose at 100 mcg (roughly 1 mcg/kg) per injection, which sits at the saturation point for GH stimulation.