GHRP-2 (Pralmorelin): The Only Growth Hormone Secretagogue That Is an Approved Drug

Last Updated: October 2026

GHRP-2, a six-amino-acid ghrelin mimetic also called pralmorelin, is the only growth hormone-releasing peptide (GHRP) approved as a drug anywhere. Kaken Pharmaceutical sells it in Japan as GHRP KAKEN 100 Injection, with a package insert and a national reimbursement price. The approval covers a single diagnostic injection, 100 mcg in adults, not treatment.

That single fact carries most of what makes GHRP-2 unusual inside the growth hormone peptides category, and it is also where most vendor copy stops being accurate. A real label exists. It has a therapeutic category code, a dose, an adverse-reaction table and a contraindication list, and none of it describes what GHRP-2 is bought for in the research-peptide market. This article works outward from the label.

The short version

• GHRP-2, also called pralmorelin, is a synthetic six-amino-acid peptide that makes the pituitary gland release growth hormone by activating the receptor for ghrelin, the hunger hormone.

• In healthy adults, one 100 mcg intravenous injection reliably triggers that release. Japan has approved it only as a single-dose diagnostic test, and the only placebo-controlled growth trial located, in 126 children, found no benefit.

• It also raises cortisol, a stress hormone, and prolactin, the hormone behind milk production; FDA cites reports of altered insulin needs and pancreatitis without establishing cause; and research vials cost a median $4.65/mg before shipping, taxes and customs (verified October 2026).

• A mass-spectrometry test, which weighs the molecule, should find about 818 daltons, and the 38 GHRP-2 certificates on file at Peptigrity score 99.19 on its recency-weighted Purity Index (verified October 2026).

• As of October 2026, FDA lists GHRP-2 among bulk substances that may pose significant safety risks in compounding, and the World Anti-Doping Agency prohibits it in sport at all times.

What is GHRP-2 approved for, and where?

GHRP-2 is approved in Japan only, as a diagnostic agent for growth hormone deficiency. Kaken Pharmaceutical markets it as GHRP KAKEN 100 Injection, generic name pralmorelin hydrochloride, in therapeutic category 7223, endocrine function diagnostic reagent, at ¥6,230 per 100 mcg vial. The label covers a single slow intravenous injection given fasting: 100 mcg in adults, and 2 mcg/kg to a 100 mcg maximum in children aged 4 to 17. It is not approved to treat anything.

Those details come from Kaken's current package insert, reproduced on KEGG MEDICUS as 医療用医薬品 : GHRP (注射用GHRP科研100) alongside the national reimbursement price.

The distinction between a diagnostic reagent and a medicine is the whole story here. Category 7223 exists to classify substances used to test a physiological function. GHRP-2 is licensed because a single injection reliably reveals whether a pituitary can release growth hormone, and for no other reason.

PMDA's review record, 審議結果報告書, shows Japan's drugs committee finding the application approvable on 19 August 2004.

What does GHRP-2's approved label say about safety?

GHRP-2's Japanese package insert, 3rd edition revised July 2025, carries the only regulated safety dataset that exists for any GHRP: heat sensation in 16.0% of patients, borborygmi and leukocytosis each at 5% or above, and hypotension, nausea and somnolence each between 0.1% and 5%. It is contraindicated in pregnancy, and the label notes pituitary apoplexy when a similar drug was given to patients with pituitary adenoma. Those rates describe a single diagnostic dose.

Read that last sentence carefully, because it is the limit of the dataset rather than a footnote to it. There is no label safety data for repeated use, because the label does not cover repeated use. A 16.0% rate of heat sensation after one injection tells you nothing about what twice-weekly subcutaneous dosing over a year does, and nothing in the regulated record fills that gap.

The pituitary apoplexy note is the one item worth carrying forward, although the label files it under other precautions and reports it for a similar drug rather than for GHRP-2 itself: it is a structural risk in people with an undiagnosed pituitary adenoma, and a diagnostic setting screens for that where self-injection at home does not.

Stop and seek care: swelling of the face or throat, difficulty breathing or hives after an injection are signs of a serious allergic reaction; spreading redness, warmth or pus at an injection site with fever is an infection; severe or persistent abdominal pain with vomiting on a GLP-1 drug can be pancreatitis; confusion, sweating or shaking on an IGF-1 or insulin-adjacent compound can be hypoglycaemia. Call your local emergency number (911 in the US, 112 in the EU, 999 in the UK, 000 in Australia) or go to an emergency department, and bring the vial and its label. Research-use vials are not approved products in any jurisdiction, even where a prescription product of the same molecule exists; no article on this site replaces a clinician who knows your history.

What is GHRP-2 chemically, and how does it separate from the other ghrelin mimetics?

GHRP-2 is a synthetic hexapeptide, D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH₂, molecular weight 818.0 g/mol in PubChem's record Pralmorelin | C45H55N9O6 | CID 6918245, CAS 158861-67-7 as the free base, carrying the INN pralmorelin and a GHS-R1a agonist mechanism. It contains 2-naphthylalanine, an unnatural amino acid, and FDA cites GHRP-2's unnatural amino acid, without naming it, as adding to the complexity of characterising the peptide. By mass it sits 55 Da below GHRP-6, 69 Da below hexarelin and 106 Da above ipamorelin.

The unnatural amino acid is not a chemistry footnote. It is one of the specific grounds FDA gives for treating GHRP-2 as difficult to characterise, and it therefore feeds directly into the compound's US regulatory position.

How do you verify GHRP-2 before you buy it?

GHRP-2 is verified before purchase with four certificate checks: mass spectrometry for identity at about 818 Da, the CAS number on the label, net peptide content for quantity, and an LAL result, the standard test for bacterial endotoxin, since FDA's file on GHRP-2 flags aggregation and peptide-related impurities. Mass is what separates it from its neighbours: molecular weights of 818 for GHRP-2, 873 for GHRP-6, 887 for hexarelin and 712 for ipamorelin are distinguishable even on low-resolution instruments, provided mass spectrometry is run at all.

The Purity Index records GHRP-2 at 99.19 across 38 recency-weighted tests from 12 laboratories (verified October 2026), against a composite of 99.50 across 11,697 tests. Thirty-eight tests is a modest evidence base — enough to be meaningful, thin enough that individual results move the average, and worth stating plainly rather than presenting as settled.

The 38 certificates behind that figure are listed on GHRP-2 lab tests, where an endotoxin result appears on 6 of them (verified October 2026).

The GHRP-2 price comparison shows 22 shops in stock, a median of $4.65/mg and a low of $2.80/mg before shipping, taxes and customs (verified October 2026). Those figures also exclude coupon codes, bulk tiers, multi-vial kits and account-gated pricing.

Identity is the check that matters most here, and Mass Spectrometry for Peptides explains how a result near 818 Da is read.

Why isn't GHRP-2 used to treat growth hormone deficiency?

GHRP-2 is not used to treat growth hormone deficiency because no treatment programme reached approval: one was tried and apparently stopped. The 2004 Drugs in R&D profile Pralmorelin records that Kaken held worldwide rights and sublicensed the United States and Canada to Wyeth, and that US development for treating growth hormone deficiency appeared to have been discontinued. A version coded KP-102 LN was then in Phase 2 in Japan for short stature. Only the diagnostic indication reached the market.

This answers the question that the approval otherwise invites. If GHRP-2 raises GH reliably enough to diagnose deficiency, the obvious next step is to use it to correct deficiency — and a major pharmaceutical company took that step, held the rights for a large market, and, as far as the record shows, did not complete it.

The public record reports the apparent discontinuation, not the reasoning behind it. What can be said is that no treatment use reached the market and the diagnostic one did.

How well does GHRP-2 diagnose growth hormone deficiency?

GHRP-2 diagnoses severe adult growth hormone deficiency well enough to be licensed for it. In A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency (Chihara et al., 2007), a 100 mcg intravenous dose produced a growth hormone peak within 60 minutes in all 77 healthy subjects and 58 deficient patients, with good reproducibility and little effect of sex, age or adiposity. A 15 mcg/L cutoff, matched to the 3 mcg/L threshold of the insulin tolerance test (ITT), the historical gold standard, diagnosed severe deficiency with high reliability.

That is a genuinely strong result and it is worth separating from everything else in this article. Matching the insulin tolerance test matters clinically because the ITT is unpleasant and carries real risk; a single well-tolerated injection that performs as well is a meaningful improvement in a diagnostic pathway. The 15 mcg/L figure applies to the study's own assay; on assays calibrated to the WHO 98/574 recombinant growth hormone standard, the same study puts the cutoff at 9 mcg/L.

It also tells you nothing about therapeutic benefit. A test that reliably provokes a hormone response is measuring capacity, not delivering an outcome.

What did GHRP-2 do in children?

GHRP-2 did not improve growth in the only placebo-controlled paediatric trial in the verified record. In that 2014 Japanese study, 126 GH-deficient children used an intranasal GHRP-2 spray or a placebo spray twice daily for 48 weeks, and height standard deviation score moved by 0.03 and 0.02 on the two doses against 0.07 on placebo, with no significant change in IGF-1. The positive paediatric growth findings come from two smaller uncontrolled studies.

The trial, Increased Secretion of Endogenous GH after Treatment with an Intranasal GH-releasing Peptide-2 Spray Does Not Promote Growth in Short Children with GH Deficiency (Tanaka et al., 2014), dosed by body weight at 50 to 200 mcg per dose, and its authors concluded that a transient rise in the body's own growth hormone does not promote growth. The uncontrolled studies point the other way. Treatment effects of intranasal growth hormone releasing peptide-2 in children with short stature (Pihoker et al., 1997) gave intranasal GHRP-2 at 5 to 15 mcg/kg, twice a day for three months and then three times a day, to 15 children with short stature, and height velocity rose from 3.7 ± 0.2 to 6.1 ± 0.3 cm/year at six months while IGF-1 and IGFBP-3 did not change.

The Pihoker growth effect held in the 6 children who stayed on treatment: height velocity was still 6.0 ± 0.4 cm/year at 18 to 24 months, and GH-binding protein rose. Effects of Eight Months Treatment with Graded Doses of a Growth Hormone (GH)-Releasing Peptide in GH-Deficient Children (Mericq et al., 1998) found the same pattern in 6 GH-deficient children given subcutaneous GHRP-2 in two-month steps of 0.3, 1.0 and 3.0 mcg/kg a day, then with GHRH added for a final two months: growth velocity rose and IGF-1 did not. The pattern is unusual — a growth effect with no IGF-1 rise behind it, which is not how growth hormone is normally understood to work. Neither study had a control group, and the one placebo-controlled trial did not reproduce the growth, so the pattern is a finding to explain rather than a result to rely on.

Changes in appetite and body weight in response to long-term oral administration of the ghrelin agonist GHRP-2 in growth hormone deficient children (Mericq et al., 2003) is, as far as we could establish, the only long-term human appetite study of GHRP-2. It dosed 10 prepubertal GH-deficient children orally for 12 months. Seven of ten children reported increased appetite during the first six months, and BMI standard deviation score moved from 0.21 ± 1.5 to 0.25 ± 1.51, which was not statistically significant. Transient, self-reported, ten children, and no meaningful weight change. The short-term evidence is stronger: in Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men (Laferrère et al., 2005), 7 lean healthy men ate 35.9% more at a buffet meal during a 270-minute subcutaneous GHRP-2 infusion than during saline. Neither study tested what repeated injections do to appetite or weight in adults.

Does GHRP-2 raise cortisol and prolactin?

GHRP-2 raises cortisol and prolactin in humans, as measured in people rather than inferred from animals. Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man (Arvat et al., 1997) gave GHRP-2 and hexarelin intravenously to six young adults, and both raised prolactin, ACTH and cortisol. What it establishes is that these compounds are not GH-specific. Marketing that presents GHRP-2 as a clean or selective growth hormone releaser is contradicted by the primary human literature, not merely unsupported by it.

That distinction matters across this whole class. For GHRP-2 and hexarelin, the selectivity question was asked in humans and answered no. For ipamorelin, it was asked only in pigs. Any "cleaner than GHRP-2" claim therefore compares a human measurement against an animal one.

Against its class, GHRP-2's position is unusual on approval and ordinary on everything else.

The three-way in-class comparison, GHRP-2 vs GHRP-6 vs Ipamorelin, sets out which selectivity claim was measured in which species. For the GHRH-analogue side of the same axis, see Sermorelin, a GHRH analogue that once held a US approval. CJC-1295 without DAC (Mod GRF 1-29) covers another GHRH analogue sold beside it.

Why is GHRP-2 still on FDA's Category 2 list when BPC-157 came off?

GHRP-2 is still on FDA's Category 2 list because nobody withdrew its nomination. It was added on 29 September 2023 to that list of bulk substances that may present significant safety risks, under the 503B outsourcing-facility policy, and FDA's page, last updated 22 April 2026, still lists it as of October 2026. In April 2026 twelve peptides left the list, including BPC-157, TB-500, KPV, MOTS-c, epitalon and semax, when their nominators withdrew nominations made under section 503A for compounding pharmacies. GHRP-2 and GHRP-6, listed under 503B, stayed.

That is a paperwork distinction, not a scientific verdict in either direction, and it is worth understanding before reading anything into the contrast. Nothing was reassessed. Some nominators withdrew and some did not. Ipamorelin shows how narrow the change was: its nomination appears on FDA's withdrawn list, yet it still sits in Category 2 under 503B.

FDA's stated rationale for the listing, on its page Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, is worth quoting in full, because it contains a safety signal that appears nowhere in the marketing:

"Compounded drugs containing GHRP-2 for injectable and nasal administration may pose risk for immunogenicity due to the potential for aggregation and peptide-related impurities. GHRP-2 also contains an unnatural amino acid, which adds to the complexity of peptide characterization. FDA is aware of reports of serious adverse advents in patients who received GHRP-2, including increased insulin requirement to maintain the blood glucose level, death of critically ill study subjects, infection and pancreatitis, though causality has not been established."

The typographical error is FDA's and is preserved. The substance is that the agency is aware of deaths among critically ill study subjects and of pancreatitis reports, with causality unestablished. Neither GHRP-2 nor GHRP-6 was on the 23–24 July 2026 agenda of FDA's Pharmacy Compounding Advisory Committee (PCAC); our FDA Peptide Regulation 2025-2026 timeline sets out what moved and when.

In sport, the World Anti-Doping Agency (WADA) names it at S2.2.4 of The 2026 Prohibited List as "GHRP-2 (pralmorelin)" under GH-releasing peptides — prohibited at all times, non-specified. Urine detection methods for pralmorelin and its metabolites have been published.

What GHRP-2 dose has actually been validated?

Only GHRP-2's diagnostic dose has been validated: 100 mcg intravenously as a single injection in adults, and 2 mcg/kg to a 100 mcg maximum in children aged 4 to 17, given slowly and fasting. Everything else, including the repeated 100 to 300 mcg subcutaneous dosing used for body composition, is community-reported, with no body-composition trial behind it and no label coverage. No adult long-term safety data was located.

The longest human exposures anywhere in the verified record are 18 to 24 months in 6 children and 12 months in 10 children, both uncontrolled and both in paediatric populations; the 126-child placebo-controlled trial ran 48 weeks and found no growth benefit. The adult injection data located are far shorter. In A five day treatment with daily subcutaneous injections of growth hormone-releasing peptide-2 causes response attenuation and does not stimulate insulin-like growth factor-I secretion in healthy young men (Nijland et al., 1998), nine healthy men aged 20 to 25 were given 100 mcg under the skin once a day, and their peak growth hormone response fell from 83 to 51 mcg/L between day 1 and day 5, with no rise in IGF-1.

The longest adult exposure located used a continuous infusion rather than injections. In Sustained Elevation of Pulsatile Growth Hormone (GH) Secretion and Insulin-Like Growth Factor I (IGF-I), IGF-Binding Protein-3 (IGFBP-3), and IGFBP-5 Concentrations during 30-Day Continuous Subcutaneous Infusion of GH-Releasing Peptide-2 in Older Men and Women (Bowers et al., 2004), 17 healthy older men and women received 1 mcg/kg an hour under the skin for 30 days: growth hormone secretion stayed above the saline level, IGF-1 rose and held, and safety screening tests remained normal. Neither adult study measured body composition, so nothing in that record transfers to an adult dosing for body composition.

The table sets out each GHRP-2 dose this article cites by its evidence form; only the first two rows are approved.

Treat the reconstitution arithmetic as arithmetic only: the GHRP-2 Reconstitution Calculator converts a chosen dose into a syringe volume, and no published source tells you which dose to choose outside the diagnostic setting.

Which GHRP-2 claims survive the evidence?

GHRP-2's two strongest claims hold and the rest do not. Reliable growth hormone release is established in the 77 healthy adults of the diagnostic validation, and the approval claim is true but narrow, covering a single diagnostic dose in one country. Approval to treat GH deficiency is outright false. Appetite stimulation is shown only acutely, children's growth failed its only placebo-controlled test, muscle building in adults has no data at all, and safety for ongoing use is unknown.

Taken together, the evidence maturity is Moderate for growth hormone release and diagnosis and Sparse for every treatment use.

The human record behind those verdicts is nine studies, only two of them with more than a hundred participants.

Against that record, the claims made for GHRP-2 score as follows.

The trial that would settle this

The trial that would settle GHRP-2 recruits adults rather than children, since every months-long human study of GHRP-2 is paediatric, and measures body composition and function rather than height velocity. It doses repeatedly over months with safety monitoring, because label safety covers one injection, and it tracks cortisol, prolactin, glucose and insulin, because FDA cites increased insulin requirement among its reported concerns. The approved diagnostic dose would serve as the reference arm.

Where this leaves GHRP-2

GHRP-2 is the most regulated compound in its class and the least mysterious. There is a label, an adverse-reaction table, a validated diagnostic cutoff at 15 mcg/L across 135 subjects, and a 2004 drug profile recording that its US treatment programme appears to have stopped. Every one of those is a real document, which is more than any sibling GHRP can offer. What none of them describes is the way GHRP-2 is actually used.

What is missing is any evidence for what it is actually sold for. The approved use is one injection to answer a clinical question. The market use is months of repeated dosing in healthy adults for body composition, which has never been studied — and FDA's own file notes reports of pancreatitis, altered insulin requirements and deaths among critically ill subjects, with causality unresolved.

Peptide Lab Tests indexes the shop-level certificates for every compound. Peptide suppliers, ranked by lab tests and reviews holds each seller's record, from its lab tests to its buyer reviews.

Frequently Asked Questions

Is GHRP-2 an approved drug?

Yes, in Japan — as pralmorelin hydrochloride, marketed by Kaken Pharmaceutical as a diagnostic agent for growth hormone deficiency. It is approved to test pituitary function with a single injection, in therapeutic category 7223, and it is not approved to treat anything.

Why isn't GHRP-2 used as a treatment if it raises growth hormone?

It was tried. Kaken sublicensed US and Canadian rights to Wyeth for treating growth hormone deficiency, and that development appears to have been discontinued. A version coded KP-102 LN was in Phase 2 in Japan for short stature in 2004, and only the diagnostic use reached the market. The only placebo-controlled growth trial located, an intranasal spray given to 126 GH-deficient children for 48 weeks, found no benefit.

Does GHRP-2 raise cortisol?

Yes. It was measured directly in humans alongside hexarelin, with effects on prolactin, ACTH and cortisol as well as GH. GHRP-2 is not a GH-specific compound, and the human literature says so rather than being silent on it.

Does GHRP-2 increase appetite?

Acutely, yes: in a 2005 study, 7 lean healthy men ate 35.9% more at a buffet meal during a 270-minute subcutaneous GHRP-2 infusion than during saline. The only long-term data, 12 months of oral dosing in 10 GH-deficient children, found 7 reporting increased appetite in the first six months and no significant change in BMI standard deviation score. Neither study tested repeated injections in adults.

Why is GHRP-2 still on FDA's Category 2 list when BPC-157 came off?

Because the twelve peptides removed in April 2026 came off when their nominators withdrew nominations made under section 503A, the compounding-pharmacy route. GHRP-2 and GHRP-6 are listed under 503B, for outsourcing facilities, and nobody withdrew either nomination. It is a procedural difference rather than a safety reassessment of either group.

Is GHRP-2 banned in sport?

Yes — named at WADA S2.2.4 as "GHRP-2 (pralmorelin)", prohibited at all times and classified as non-specified. Urine detection methods for pralmorelin and its metabolites have been published.

When should you talk to a clinician before using GHRP-2?

Talk to a clinician first if you are pregnant or could be, because the label contraindicates GHRP-2 in pregnancy. The same applies if you have a known or suspected pituitary tumour, because the label reports pituitary apoplexy (sudden bleeding or loss of blood supply in the gland) when a similar drug was given to patients with pituitary adenoma, and if you have diabetes or use insulin, because FDA lists an increased insulin requirement among the reports it holds. Stop and be seen after any unexplained reaction to a dose.

This article is for educational and informational purposes only and does not constitute medical advice. Peptides discussed may be investigational compounds not approved by the FDA (or equivalent regulators in your jurisdiction) for human use; research peptides are sold for laboratory use and are not manufactured, tested or labelled to pharmaceutical standards. Peptigrity does not recommend doses: every dose figure above is an approved-label value, a published-trial value or a community report, and is labelled as such — a community report is not a recommendation. Self-injection carries risks of infection, allergic reaction and dosing error; signs of a serious allergic reaction, an injection-site infection with fever, severe abdominal pain, or confusion and sweating on an IGF-1 or insulin-adjacent compound are medical emergencies — call your local emergency number. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.