GHRP-2

In simple words

GHRP-2 is a man-made peptide of six amino acids that boosts growth hormone release through the "hunger hormone" receptor. In Japan it is used as a diagnostic test for growth hormone deficiency.

What this molecule is

6 aa: D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH₂. Second-generation synthetic GHRP. ~817 Da.

Why it is studied

One of the most studied GHRPs. 5 human RCTs. More GH-selective than GHRP-6. Japan: approved as a diagnostic test for GH deficiency (pralmorelin). Diagnosis of adrenal insufficiency (sensitivity 83%, specificity 88%). Moderate orexigenic effect (↑appetite +35.9%, weaker than GHRP-6).

How it works

GHS-R1a + GHS-R1b → ↑IP₃ → ↑Ca²⁺ → GH exocytosis. GHRH-independent mechanism: works in the absence of hypothalamic GHRH. Moderate ↑cortisol and ↑prolactin (lower than GHRP-6). Desensitization is slower than with GHRP-6. No ↑ACTH, unlike GHRP-6.

Doses used in studies

Studies used 100–300 mcg SC 2–3 times/day; typically 1–2 mcg/kg IV or SC, for a course of 4–8 weeks. The combination with GHRH analogs (Mod-GRF, CJC-1295) was studied: synergy through different receptors. Research only.

Combined with in studies

• Mod-GRF(1-29) / CJC-1295 / Sermorelin — GHRH + GHRP: the gold standard of synergy
• GHRP-6 — NOT at the same time: competition for GHS-R1a

Level of evidence

Level A Human clinical trials. There are randomized controlled trials (RCTs), or the compound has been approved by a regulatory agency. The most reliable level. 5 human RCTs. Approved in Japan as a diagnostic agent.

Important to know

Legal status: Russian Federation: not registered as a medicinal product or dietary supplement. Not included in the lists of Government Decree No. 681 (narcotic drugs) or Government Decree No. 964 (potent substances). Research Use Only. Japan: approved as a diagnostic agent (pralmorelin). US/EU: unapproved research chemical. Australia: Schedule 4 (prescription-only, no approved products). WADA: prohibited under S2.2.4, both in and out of competition. ⚠️ Moderate ↑cortisol and ↑prolactin (unlike ipamorelin). Not approved. Research Use Only. Not a medicinal product or dietary supplement. 🔴 CONTRAINDICATIONS: active cancer (GH/IGF-1 stimulation) • pregnancy • hyperprolactinemia • diabetes mellitus (impaired glucose tolerance). 🔴 FOR ATHLETES: prohibited by WADA S2.2.4. Use = disqualification. Criminal liability under Articles 230.1–230.2 of the Criminal Code of the Russian Federation.

Studies in PubMed

1. Ipamorelin, the first selective growth hormone secretagogue. (Eur J Endocrinol, 1998)
2. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. (J Clin Endocrinol Metab, 2005)
3. Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2: a phase I study in children. (J Clin Endocrinol Metab, 1998)
4. Clinical Usefulness of the Growth Hormone-Releasing Peptide-2 Test for Hypothalamic-Pituitary Disorder. (J Endocr Soc, 2022)
5. Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects. (Clin Med Insights Cardiol, 2017)
6. Growth hormone-releasing peptide-2 stimulates GH secretion in GH-deficient patients with mutated GH-releasing hormone receptor. (J Clin Endocrinol Metab, 2001)