Compound profile
GHRP-2
Limited human dataAlso known as: Pralmorelin · KP-102
A synthetic hexapeptide ghrelin receptor agonist that stimulates growth hormone release. Notable for being the one compound in this family with a real regulatory approval, marketed in Japan as a diagnostic agent for GH deficiency under the name pralmorelin.
Overview
GHRP-2 belongs to the same family of synthetic growth hormone-releasing peptides as GHRP-6 and hexarelin, all of which act on the ghrelin receptor rather than the GHRH receptor. It was developed in the 1990s and refined for a stronger, more selective GH-releasing profile than the original GHRP-6 while producing somewhat less appetite stimulation and hormonal side effects.
Its most concrete claim to legitimacy is regulatory: under the name pralmorelin, GHRP-2 received approval from Japan's Pharmaceuticals and Medical Devices Agency in 2004 as a single-dose diagnostic agent, used to test whether a patient's pituitary can still release growth hormone. It is used clinically in Japan as an alternative to the insulin tolerance test, which carries meaningfully more risk because it requires inducing hypoglycemia.
Outside Japan, GHRP-2 is not approved for any use and circulates as a research chemical, discussed in fitness and anti-aging communities as a GH-boosting peptide, a use case that has never been the basis of its actual regulatory approval or its Phase II trials for pediatric short stature, which did not advance to market.
Mechanism (plain language)
Binds the ghrelin receptor (GHS-R1a) on the pituitary, stimulating GH release through calcium-channel and protein kinase C signaling that is separate from and additive to the GHRH pathway.
How it works
GHRP-2 activates the ghrelin receptor on pituitary somatotrophs, triggering calcium influx that drives GH secretion, a mechanism distinct from the cAMP pathway that GHRH and its analogs like sermorelin use. Research on isolated pituitary cells suggests GHRP-2 may also partially engage the GHRH receptor pathway at the cellular level, which is thought to be part of why combining a GHRP with a GHRH analog produces a synergistic GH release greater than either compound alone, a combination frequently discussed in research and clinical contexts alike.
Because GHRP-2 mimics ghrelin, the stomach-derived hormone that also drives hunger, it reliably increases food intake in human studies, an effect shared with ghrelin itself and distinguishing it, along with the rest of the GHRP family, from GHRH-class secretagogues that do not meaningfully affect appetite.
What research suggests
Clinical pharmacology in Japan established GHRP-2 as a reliable, single-dose GH stimulation test with a better safety profile than the insulin tolerance test. Human data outside that diagnostic use case, such as for body composition or recovery from repeated dosing, is much thinner.
Reported benefits
What studies, case reports, and the research literature describe, not guaranteed outcomes. The trials behind these findings are in the studies below.
Established diagnostic reliability
As pralmorelin, GHRP-2 is used clinically in Japan as a single-dose GH stimulation test, offering a safer alternative to the insulin tolerance test for diagnosing GH deficiency.
Reliable GH release with fewer side effects than GHRP-6
Pharmacology studies describe GHRP-2 as producing strong GH release with comparatively milder appetite and hormonal side effects than the older GHRP-6.
Appetite stimulation
A controlled study in healthy men found GHRP-2 increased food intake, similar to ghrelin itself, a documented effect that some research has explored for cachexia and appetite-loss conditions.
Uncertainties & risks
Its regulatory approval is narrowly for single-dose diagnostic use, not for repeated dosing to raise GH or IGF-1 over time, so its long-term safety profile for that off-label use is not established. Appetite stimulation, useful in a wasting-disease context, is an unwanted side effect for people using it for body composition goals.
GHRP-2's Japanese approval as pralmorelin is specifically for a single diagnostic dose under clinical supervision, and that narrow, well-studied use case should not be read as approval for the repeated self-administered dosing protocols common in research-chemical circles. Like other ghrelin receptor agonists, it raises cortisol and prolactin alongside GH, generally to a lesser degree than GHRP-6, and it reliably increases appetite, which is a documented pharmacological effect rather than an incidental side effect. Outside Japan it has no regulatory status, and sourcing as a research chemical means purity and dosing consistency are not independently verified.
Side effects
Commonly reported
- Increased appetite: Documented in a controlled human feeding study
- Mild cortisol and prolactin elevation: Reported at higher doses, less pronounced than GHRP-6
- Flushing or warmth after dosing: Reported in diagnostic-use trials
Reported in the cited literature, not a complete list, and not medical advice. Individual responses vary; consult a qualified professional.
STACKD study summaries
Start with our in-house roundups, plain-language synthesis of the research, with primary sources cited at the bottom of each.
Primary sources
Secondary citations for verification. Prefer the STACKD summary above for context before opening these.