GHRP-2 Evidence Guide
Evidence for GHRP-2 is too preliminary to support a research protocol with confidence. Like GHRP-6, it raises cortisol and prolactin alongside GH, limiting its practical utility. It is more potent than GHRP-6 but that potency comes with the same hormonal side effects. Of the Growth Hormone secretagogues in this library, ipamorelin or MK-677 are better-evidenced starting points.
Our Take
Evidence for GHRP-2 is too preliminary to support a research protocol with confidence. Like GHRP-6, it raises cortisol and prolactin alongside GH, limiting its practical utility. It is more potent than GHRP-6 but that potency comes with the same hormonal side effects. Of the Growth Hormone secretagogues in this library, ipamorelin or MK-677 are better-evidenced starting points.
- Evidence context
- GHRP receptor pharmacology, second-generation GHRP mechanistic research
- Evidence grade
- Level C
- Confidence
- Low
- Reference context
- Reported research reference: 100-200mcg subcutaneous, up to three times daily - but ipamorelin is preferred for cleaner GH stimulation
Benefits and Evidence
- Growth Hormone Release: Level B, includes human evidence - Considered the most potent GHRP for GH stimulation. Approved as a diagnostic agent for GH deficiency in Japan based on its reliable, dose-dependent GH release.
- Appetite Stimulation: Level C, includes human evidence - Less appetite stimulation compared to GHRP-6, though still present due to ghrelin receptor agonism. Generally considered better tolerated.
- Cortisol and Prolactin Effects: Level C, includes human evidence - Modest transient increases in cortisol and prolactin, less pronounced than GHRP-6 but greater than ipamorelin.
Side Effects and Warnings
- Mild appetite increase
- Transient cortisol elevation
- Mild prolactin increase
- Water retention
- Flushing
- Dizziness
- Not FDA approved (approved in Japan for diagnostic use only)
- Should not be used in patients with active malignancy
Research Dosage References
- <strong>Subcutaneous injection</strong> - 100-300 mcg - 2-3 times daily - Research dosage. Often combined with a GHRH analog like CJC-1295 for synergistic GH release.
- <strong>Intravenous</strong> - 1-2 mcg/kg - Single dose (diagnostic) - Approved diagnostic dose in Japan for GH deficiency assessment.
Mechanism of Action
GHRP-2 binds to the growth hormone secretagogue receptor 1a (GHSR1a) with high affinity, stimulating GH release from anterior pituitary somatotrophs. Its binding affinity and selectivity profile result in the strongest GH-releasing effect among the classical GHRP hexapeptides. Like other GHRPs, GHRP-2 acts at both the pituitary and hypothalamic levels. At the hypothalamus, it stimulates GHRH release from arcuate nucleus neurons while simultaneously reducing somatostatin inhibitory tone. This dual action amplifies the GH-releasing signal reaching the pituitary. Compared to GHRP-6, GHRP-2 produces less appetite stimulation due to somewhat different receptor binding kinetics at hypothalamic orexigenic centers. It also causes smaller elevations in cortisol and prolactin, making it a cleaner GH secretagogue with a more favorable side effect profile.
Legal Status
Approved in Japan as a diagnostic agent (GHRP Kaken). Not approved by FDA. Available as research chemical elsewhere. Banned by WADA.
Primary Sources
- GH-releasing activity of GHRP-2, a synthetic GH secretagogue, in normal and GH-deficient subjects. Journal of Clinical Endocrinology & Metabolism, 1990.
- Pralmorelin (GHRP-2) as a diagnostic test for growth hormone deficiency in adults. Endocrine Journal, 2006.
Quick Answers
Where is the strongest evidence for GHRP-2?
Evidence for GHRP-2 is too preliminary to support a research protocol with confidence. Like GHRP-6, it raises cortisol and prolactin alongside GH, limiting its practical utility. It is more potent than GHRP-6 but that potency comes with the same hormonal side effects. Of the Growth Hormone secretagogues in this library, ipamorelin or MK-677 are better-evidenced starting points. Evidence context: GHRP receptor pharmacology, second-generation GHRP mechanistic research.
What are the main side effects of GHRP-2?
GHRP-2 side effects and warning signals include Mild appetite increase, Transient cortisol elevation, Mild prolactin increase, Water retention, and Flushing.
What evidence level is GHRP-2?
GHRP-2 is rated Level C; the listed research status is Preclinical.