What GHRP-2 is and how it works
GHRP-2 is a six-residue synthetic peptide, D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH₂, also known as pralmorelin and as KP-102. It came out of the same line of work that produced GHRP-6, refined for a stronger growth hormone response from a smaller amount of material. Half its residues are in the D configuration or are not proteinogenic at all, and the C-terminus is amidated, which is what keeps a peptide this short intact in plasma.
It acts on GHS-R1a, the ghrelin receptor, on somatotroph cells in the pituitary and on neurons in the hypothalamus. Two things happen at once: the pituitary cells release stored growth hormone, and hypothalamic somatostatin tone falls, lifting the brake that normally keeps secretion down between pulses. This is a different pathway from the one GHRH analogues use, and the difference is measurable. Give a GHRP and a GHRH analogue together and the growth hormone response is larger than either produces alone, a result reported repeatedly in human studies since the 1990s.
The receptor was never a growth hormone receptor in any exclusive sense, which is the complication with this family. It is the receptor for ghrelin, the stomach hormone that signals hunger, and it sits on cells that also govern corticotroph output. So GHRP-2 does more than release growth hormone: it produces small rises in ACTH, cortisol and prolactin, and it increases appetite. Ipamorelin was designed specifically to lose those extra effects.
What the research on GHRP-2 shows
The most solid use is diagnostic. Japan licenses GHRP-2 as an agent for testing growth hormone deficiency: a single intravenous dose is given, blood is sampled over the following hour, and the peak growth hormone concentration is compared against a threshold. Provocation testing of this kind has a long history, and a peptide that reliably produces a large pulse is useful precisely because the read-out is the pulse itself, not a clinical outcome. No regulator has approved GHRP-2 as a treatment for anything.
The appetite effect has been measured directly. Laferrère et al. (2005) infused GHRP-2 in healthy lean men and food intake rose by about a third against placebo. That is a small acute study, but a clear one, and it matters for anyone running metabolic research in which food intake is a variable rather than an endpoint.
What is missing
There are no controlled trials of GHRP-2 for body composition, muscle mass, recovery or physical performance. The growth hormone response is not in doubt; everything downstream of it in people is. Attenuation of the response with prolonged administration has been described for this family, most clearly for hexarelin, which is a reason to treat short-term pulse data as short-term pulse data.
Doses of GHRP-2 used in published research
| Setting | Participants | Design | Read-out |
|---|---|---|---|
| Diagnostic test, Japan | Adults assessed for GH deficiency | Single intravenous dose, GH sampled across the following hour | Peak GH against a diagnostic threshold |
| Laferrère et al. (2005) | Healthy lean men | Intravenous infusion against placebo | Food intake about 36% higher |
| Pharmacology studies | Healthy volunteers | Single intravenous or subcutaneous doses | Dose-related GH rise, with smaller rises in cortisol and prolactin |
| Combination studies | Healthy volunteers | A GHRP given together with GHRH | More GH than either peptide alone |
Outside the Japanese diagnostic product, whose dosing is set by its own licence, no validated human dose exists for GHRP-2. Published amounts belong to single-dose testing protocols and short infusions, and none of them establishes a schedule for repeated administration. These are study designs, not instructions, and the peptide is sold for laboratory research only.
Safety and side effects of GHRP-2
Most of what is known comes from short human studies, which is enough to describe acute effects and not enough to describe anything else.
- Cortisol and prolactin. Modest, dose-related rises are reported in human work. They are the reason the more selective peptides in this family were developed, and the reason GHRP-2 is a poor choice when adrenal or pituitary read-outs are part of an experiment.
- Appetite. Food intake rose by roughly a third in the study above. In any metabolic model this is a confounder before it is a side effect.
- Glucose and insulin. Growth hormone opposes insulin, and ghrelin-receptor agonists acutely reduce insulin secretion in human studies. Both effects push blood glucose in the same direction.
- Loss of response. Continued administration of peptides in this class can blunt the growth hormone response, a reversible effect documented most clearly for hexarelin.
- Fluid retention and joint symptoms. These follow sustained growth hormone excess and are class concerns rather than findings from GHRP-2 trials, which have never run long enough to see them.
Regulatory status of GHRP-2 in Europe
GHRP-2 has no marketing authorisation in the European Union. The Japanese licence is a national approval outside the EU, and it covers a diagnostic procedure rather than treatment, so it does not make the peptide a medicine anywhere in Europe. In the EU a medicinal product needs an authorisation from the EMA or a national agency; material sold as a research peptide has none and is not sold for human use. Rules on possession and personal import are set member state by member state.
In sport, growth hormone secretagogues including GHRP-2 are named in section S2 of the WADA Prohibited List and are banned at all times, in and out of competition. The comparison with the rest of the family is set out in our guide to growth hormone secretagogues.
Sourcing and quality: GHRP-2 for research
King Peptides does not stock GHRP-2. The closest product in its catalogue is the CJC-1295 + Ipamorelin Blend 5/5 mg, and the word closest is doing real work in that sentence: the blend contains a different ghrelin-receptor agonist, one selected to avoid the cortisol and prolactin effects described above, together with a GHRH analogue. It is the nearest thing in the same research class, not the same compound. A study that needs GHRP-2 specifically needs GHRP-2, and the honest answer is to look elsewhere for it.
The quality questions are the same wherever the material comes from. Ask for a lot-specific certificate of analysis with HPLC purity of at least 99% and a mass spectrometry result matching the 818.0 Da in the panel on this page, and check that the lot number on the document is the one printed on the vial. King Peptides dispatches from the Netherlands, inside the EU, with delivery usually 1–2 business days within the Netherlands and 3–5 business days elsewhere in the EU on the shop's own estimate, and no customs inside the union; non-EU destinations such as the UK, Switzerland and Norway can attract import rules and duties. Packaging is neutral and tracked, and buyers confirm at checkout that they order for research and are 18 or older. Our guides to reading a certificate of analysis and to storage and reconstitution cover the details.
GHRP-2 frequently asked questions
Is GHRP-2 an approved medicine? It is licensed in Japan as a diagnostic agent for growth hormone deficiency. That is an approval for a test, not a treatment, and it does not extend to the European Union.
Is GHRP-2 stronger than ipamorelin? As a growth hormone releaser it is generally described as the more potent of the two on a milligram basis. Ipamorelin was not built to win that comparison; it was built to leave cortisol and prolactin alone.
Does GHRP-2 raise cortisol? Yes, modestly and in proportion to dose, along with ACTH and prolactin. The rises are smaller than the growth hormone response but they are real and they are measurable.
Can I order GHRP-2 from King Peptides? No. It is not in the catalogue. The blend described above is the closest product in the same class, which is not the same thing as a substitute for the compound on this page.
Research use only. GHRP-2 is described here for laboratory and scientific research. Research material carries no marketing authorisation, whatever the status of the molecule as a medicine elsewhere, and it is not intended for human or veterinary use. Nothing on this page is medical advice, and the dosing information above summarises published study designs. Always comply with the laws that apply in your country.