What is GHRP-2 (Pralmorelin)? What it does, benefits and what the evidence shows

GHRP-2, also known by its drug name pralmorelin, is a synthetic peptide that mimics ghrelin and prompts the pituitary to release a large burst of growth hormone. It has one approved use that we could find: in Japan, as an injection given once to help diagnose growth hormone deficiency. It is not approved anywhere we could find as a treatment, and the claims that sell it on the grey market (muscle, fat loss, recovery, anti-aging) have no controlled human trial behind them.

What GHRP-2 is and how it works

GHRP-2 is one of a series of small growth hormone-releasing peptides developed by Polygen in Germany and by Cyril Bowers's group at Tulane University in the US. These compounds mimic ghrelin, the 28-amino-acid hormone that regulates growth hormone release (Adis drug profile, Drugs in R&D, 2004). The Kaken Pharmaceutical company later held the marketing rights to it, and in the same profile it is listed under the name pralmorelin and under the code KP-102.

Like other GHRPs, it doesn't supply growth hormone itself; it prompts the pituitary to release its own. That means it depends on a pituitary that still responds. In eleven adults with isolated growth hormone deficiency caused by a mutated GHRH receptor, GHRP-2 raised growth hormone about 4.5-fold, versus about 79-fold in normal controls; the authors concluded that GHRP-2 works partly on the pituitary directly, without needing the GHRH signal (Gondo et al., Journal of Clinical Endocrinology & Metabolism, 2001).

The approved use is a diagnostic test

Japan's drug regulator, PMDA, lists a single-use injection called GHRP Kaken 100 (in Japanese, 注射用GHRP科研100), containing pralmorelin hydrochloride. Its indication is "the diagnosis of growth hormone secretion deficiency" (成長ホルモン分泌不全症の診断), sales began in February 2005, and the package insert was revised most recently in July 2025 (PMDA package insert). The insert contraindicates use in pregnancy and lists a heat sensation (16.0% of cases), low blood pressure, nausea, dizziness, facial flushing and small lab changes among its adverse reactions.

How the test works: in healthy people GHRP-2 produces a big growth hormone spike, while in people with growth hormone deficiency the spike is much smaller. The 2004 Adis profile said a threshold peak of 15 micrograms per liter separated patients from healthy controls (Adis, 2004). The same 2004 profile said a US phase II program for growth hormone deficiency with Wyeth appeared to have been discontinued, and that a Japanese short-stature program was then in phase II; we found no later approval for either.

That is the whole approved story: a one-off test, in one country, not a treatment. A 2019 forensic-chemistry paper summarizes it the same way, noting that of all the GHRPs developed as drug candidates, only GHRP-2 has received a clinical approval (Popławska and Błażewicz, Drug Testing and Analysis, 2019).

What people use it for

What the research actually shows

Growth hormone release and the diagnostic test

The diagnostic case is the best-tested part. In a validation study of 77 healthy people and 58 patients with severe growth hormone deficiency (defined by the standard insulin tolerance test), the peak growth hormone response to a single intravenous GHRP-2 injection was far lower in patients (about 1 microgram per liter) than in healthy people (about 85). Repeat tests were reproducible, results were only mildly affected by age and adiposity, and a cut-off of 15 micrograms per liter corresponded to the 3 microgram cut-off used for the insulin test (Chihara et al., European Journal of Endocrinology, 2007). A Japanese comparison in 71 patients with pituitary tumors judged the GHRP-2 test an acceptable alternative to the insulin tolerance test, though the authors noted that criteria should be adjusted to each population (Endocrine Journal, 2013). In 56 children, the test correlated with the insulin tolerance test and took an hour or less (Journal of Pediatric Endocrinology & Metabolism, 2010).

There are limits. In a retrospective study of 23 adolescents, two patients passed the GHRP-2 cut-off but failed other tests, and the authors suggested the cut-off may miss some deficient patients (Journal of Pediatric Endocrinology & Metabolism, 2024). A test that produces a big, reliable spike is a good diagnostic; it is not evidence that the spike does anything for you.

The test isn't only about growth hormone. GHRP-2 also stimulates ACTH, the pituitary signal that drives cortisol. In six patients with hypothalamic or pituitary disorders, GHRP-2 produced significant ACTH release, which the authors read as evidence of direct ACTH-releasing activity (Kimura et al., Endocrine Journal, 2010). If you have seen GHRP-2 compared with ipamorelin, this off-target hormone effect is the usual contrast; see our ipamorelin guide and the sibling hexarelin guide, which describes similar cortisol and prolactin effects.

Appetite

GHRP-2 does what ghrelin does to hunger. In seven lean, healthy men given a GHRP-2 infusion versus saline, then offered a buffet meal, every man ate more on GHRP-2; average intake rose about 36% (Laferrère et al., Journal of Clinical Endocrinology & Metabolism, 2005). That is a tiny, short study, but a consistent one, and it is probably the most reliable non-diagnostic effect on record. It also helps explain why GHRP-2 shows up in conversations about weight gain, and why it is a poor fit for anyone who wants the opposite.

Prolonged critical illness

A small randomized study in 33 men with prolonged critical illness tested a short course of placebo, GHRP-2 alone, GHRP-2 with TRH, or GHRP-2 with TRH and pulsed GnRH. GHRP-2 alone reactivated growth hormone secretion and normalized IGF-I and related proteins. But the metabolic benefits the authors were after (reduced ureagenesis, higher osteocalcin) appeared only with the combined regimens, and by the end of the course GHRP-2 alone raised lactate and white blood cell counts (Van den Berghe et al., 2002). This is intensive-care research at a small scale, and it says nothing about healthy people.

Repeated use

Whether the response fades with repeated dosing is less clear for GHRP-2 than for its sibling hexarelin. In a 1996 report, Bowers and Granda-Ayala found that whether the growth hormone response becomes desensitized during chronic GHRP-2 administration depends partly on the dosage and frequency (Journal of Pediatric Endocrinology & Metabolism, 1996). That study didn't report muscle or fat outcomes in its abstract.

Muscle, fat loss, recovery and anti-aging

We found no controlled human trial of GHRP-2 for muscle growth, fat loss, recovery or aging. The muscle-protection findings are from cultured muscle cells (Yamamoto et al., Life Sciences, 2008) and the anti-inflammatory findings from arthritic rats (Granado et al., AJP Endocrinology & Metabolism, 2005). Those are hypotheses, not results in people.

Side effects and risks

The approved diagnostic is a single injection given under medical supervision, so its safety data doesn't translate to repeated self-administered use. What we can say:

• The label. The Japanese insert lists a heat sensation (16.0% of cases), low blood pressure, nausea, dizziness, facial flushing, raised ALT and higher white blood cell counts, and contraindicates use in pregnancy (PMDA).
• FDA's view. GHRP-2 is on FDA's list of bulk drug substances with significant safety risks for compounding (503B), added September 29, 2023. FDA cites potential immunogenicity from aggregation and peptide-related impurities, notes GHRP-2 contains an unnatural amino acid that complicates characterization, and says it is aware of reports of serious adverse events in patients who received it, including increased insulin requirement, death of critically ill study subjects, infection and pancreatitis, though causality has not been established (FDA, Category 2 bulk drug substances, page current as of April 22, 2026). Those are FDA's words, not confirmed harms.
• Off-target hormones and appetite. ACTH release (Kimura et al., 2010) and a marked rise in food intake (Laferrère et al., 2005).
• No long-term data. We found no long-term safety study in healthy adults.
• Sport. GHRP-2 (pralmorelin) is named on the 2026 WADA Prohibited List, in the growth hormone-releasing peptide class, prohibited at all times (WADA Prohibited List 2026).

There is also a documented quality problem in this corner of the market. GHRP-2 has been identified and quantified in tablets sold as an over-the-counter nutritional supplement (Thomas et al., Drug Testing and Analysis, 2010), and a modified glycine analogue of GHRP-2 was identified in a seized injection vial (Popławska and Błażewicz, 2019). Neither tells you how common such products are, but both say a vial's label is not proof of what is inside.

What the lab tests show

As of September 29, 2026, VendorVerify's database has no lab results for GHRP-2. That doesn't mean the vials are good or bad; it means no report has been submitted that we can count. If you have had a GHRP-2 vial tested, submitting the report is the fastest way to change that.

Because we don't have enough lab data on this compound to rank vendors for it, here are the highest-ranked vendors across all compounds right now. A vendor's overall record is a signal, not a guarantee for a compound they have never had tested.

Buying smarter

With no compound-specific data, lean on the general checks. Look at each vendor's full record and how many reports sit behind the score. Treat a vendor-posted COA as a starting point (how to read a peptide COA, fake peptide COAs). Paying for identity, purity and quantity testing on your own vial is worth it for a compound with no track record in our data; how to get a peptide tested walks through it, and endotoxin in research peptides covers when to add that test.

If a report comes back with a fail, stop using that batch, tell anyone who bought from the same run, bring the report to the vendor, and submit it to VendorVerify. Buyers who research GHRP-2 often also look at hexarelin, ipamorelin, sermorelin and CJC-1295; the peptide hub lists every compound we track.

Database figures are from VendorVerify as of September 29, 2026. This isn't medical advice; GHRP-2 sold outside a licensed setting is unregulated and sold for research use only, and its only approval we could find is a Japanese one-time diagnostic.