GHRP-2

Think of it like a key fob that reliably makes the pituitary honk out a burst of growth hormone on demand. That single honk is useful and well-proven as a diagnostic test, like a mechanic pressing the fob once to check the alarm works. But pressing it over and over for years to tune up your body is something almost nobody has studied. It also comes with a built-in side effect: every press rings the dinner bell.

GHRP-2 is an agonist at the ghrelin receptor (GHS-R1a) on pituitary somatotrophs and in the hypothalamus. Activation couples through Gq/11 to phospholipase C, raising intracellular calcium and triggering growth hormone release while reducing inhibitory somatostatin tone. Because it acts on the ghrelin receptor it shares ghrelin's appetite-stimulating effect and can modestly raise cortisol and prolactin. It is administered by injection.

Research contexts. Not proven uses, and not recommendations.

GHRP-2 reproducibly evokes a sharp GH pulse in humans, the basis of its only regulatory approval: Japan licensed pralmorelin in 2004 as a single-dose provocation test for GH deficiency. Controlled studies confirm its ghrelin-like effect. A subcutaneous infusion study in lean healthy men found it increased ad libitum food intake by roughly a third versus saline, a finding later extended to obese subjects. For the chronic uses it is actually sold for online (muscle gain, fat loss, recovery, anti-ageing), human evidence is essentially absent.

• !Not a licensed medicine in the UK. Grey-market product is sold as an unlicensed research chemical labelled 'not for human consumption', with no guarantee of identity, purity, sterility or correct content
• !Stimulates appetite via the ghrelin receptor, which works against the fat-loss goals it is often marketed for
• !Can raise cortisol and prolactin. Chronic GH-axis stimulation carries theoretical risks of insulin resistance, fluid retention, joint pain and IGF-1-driven growth signalling
• !The approved human use is a single diagnostic dose only. Repeated or long-term self-administration is unstudied and unlicensed
• !Banned by WADA at all times in sport as a growth hormone secretagogue
• !No long-term human safety data for the chronic anabolic or anti-ageing use that drives most grey-market demand

Not a licensed medicine in the UK and not approved by the MHRA for any indication. Its only known marketing authorisation is in Japan (2004, PMDA), as a single-dose diagnostic agent for growth hormone deficiency. It is not licensed in the UK even for diagnostic use. Any clinical use would be unlicensed. Material sold online to UK buyers is an unlicensed research chemical, typically labelled 'not for human consumption' to sidestep medicines law. Supplying it for human use would fall foul of the Human Medicines Regulations 2012. It is also prohibited in sport by WADA at all times.

1. 01
   Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men — Laferrère B, Abraham C, Russell CD, Bowers CY, Journal of Clinical Endocrinology & Metabolism (2005)

   Controlled human infusion study confirming the orexigenic, ghrelin-like effect of GHRP-2.

2. 02
   Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP-102 D, KP-102 LN, KP-102D, KP-102LN — Adis profile (Drugs in R&D), Drugs in R&D (2004)

   Drug development profile covering pralmorelin's pharmacology and its diagnostic development/Japanese approval as a GH secretagogue.

3. 03
   Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects — Berlanga-Acosta J, et al., Clinical Medicine Insights: Cardiology (2017)

   Review tracing the GHRP family from Bowers' enkephalin-derived work; useful for class context and mechanism.

4. 04
   Obese subjects respond to the stimulatory effect of the ghrelin agonist growth hormone-releasing peptide-2 on food intake — Laferrère B, et al., Obesity (Silver Spring) (2006)

   Human study extending the appetite-stimulating finding to obese subjects.