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

Almost every growth hormone secretagogue on the market is unapproved everywhere. GHRP-2 is the exception: Kaken Pharmaceutical sells it in Japan as GHRP KAKEN 100 Injection, with a package insert and a national reimbursement price. The approval covers one diagnostic injection, 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.

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 ¥6,684 per 100 µg vial. The label covers a single slow intravenous injection given fasting: 100 µg in adults, and 2 µg/kg to a 100 µg maximum in children aged 4 to 17. It is not approved to treat anything.

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.

We could not confirm the exact approval year from a primary document — trade literature places it in the mid-2000s, and we are not publishing a date we could not verify. Compound identity details are on the GHRP-2 compound page.

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

GHRP-2's Japanese package insert, 2nd edition revised July 2022, 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 or vomiting and somnolence each between 0.1% and 5%. It is contraindicated in pregnancy, with pituitary apoplexy flagged as a risk in 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 warning is the one item on the list that is dose-independent and worth carrying forward: it is a structural risk in people with an undiagnosed pituitary adenoma, and a diagnostic setting screens for that where a self-administered protocol does not.

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

Somebody tried and stopped. GHRP-2's development history, documented in Drugs in R&D in 2004, records that Kaken held worldwide rights and sublicensed the United States and Canada to Wyeth, and that US development for treating growth hormone deficiency was discontinued. A separate formulation remained in Phase 2 for short stature. Only the diagnostic indication survived, which is why a compound that reliably raises growth hormone is licensed to measure the pituitary rather than to drive it.

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 did not complete it.

The public record documents the discontinuation, not the reasoning behind it. What can be said is that the therapeutic programme ended and the diagnostic one did not.

How well does GHRP-2 diagnose growth hormone deficiency?

Well enough to license. Chihara et al. 2007, in European Journal of Endocrinology, tested 77 healthy subjects and 58 patients with confirmed growth hormone deficiency. A 100 µg intravenous dose produced peak GH within 60 minutes in every subject, with good reproducibility and minimal influence from sex, age or adiposity. At a 15 µg/L cutoff, sensitivity and specificity were comparable to the insulin tolerance test, the historical gold standard.

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.

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?

Two small uncontrolled paediatric studies exist and they point in different directions. Pihoker et al. 1997 gave intranasal GHRP-2 at 5 to 20 µg/kg 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. Mericq et al. 2003 dosed 10 prepubertal GH-deficient children orally for 12 months, with 7 of 10 reporting increased appetite and no significant BMI change.

The Pihoker growth effect held: height velocity was still 6.0 ± 0.4 cm/year at 18 to 24 months, and GH-binding protein rose. The pattern is unusual — a real growth effect with no IGF-1 rise behind it, which is not how growth hormone is normally understood to work. The study was open-label and uncontrolled in 15 children, so the pattern is a finding to explain rather than a result to rely on.

The Mericq study is, as far as we could establish, the only human appetite trial for any GHRP. 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. That is the entire evidential basis for GHRP-2's reputation as an appetite compound.

Does GHRP-2 raise cortisol and prolactin?

Yes, and it was measured in people rather than inferred from animals. Arvat et al. 1997, in Peptides, measured GH, prolactin, ACTH and cortisol after both GHRP-2 and hexarelin in humans, and the paper remains the human reference point for the class. 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.

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, 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 that FDA cites explicitly as a reason the compound is harder to characterise analytically. 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.

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

For the three-way in-class comparison, see GHRP-2 vs GHRP-6 vs ipamorelin. For the GHRH-analogue side of the same axis, see sermorelin and CJC-1295 without DAC.

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

Because nobody withdrew its nomination. GHRP-2 was added to FDA's Category 2 list of bulk substances that may present significant safety risks on 29 September 2023, under the 503B outsourcing-facility list, and that page remains current as of 22 April 2026. In April 2026 sixteen substances left the list, including BPC-157, TB-500, KPV, MOTS-c, epitalon and semax, when their original nominators withdrew the nominations. GHRP-2 and GHRP-6 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.

FDA's stated rationale for the listing 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 PCAC agenda; our FDA peptide regulation timeline sets out what moved and when.

In sport, WADA's 2026 Prohibited List names it at S2.2.4 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 the diagnostic dose. That is 100 µg intravenously as a single injection in adults, and 2 µg/kg to a 100 µg 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 convention with no 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 15 children and 12 months in 10 children, both uncontrolled and both in paediatric populations. Nothing in that record transfers to an adult dosing for body composition.

Treat the reconstitution arithmetic as arithmetic only: the peptide dosing calculator and the reconstitution calculator convert 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 in humans is established across 135 subjects in 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 weak and transient, muscle building in adults has no data at all, and safety for ongoing use is unknown.

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

GHRP-2's mass separates it cleanly from its neighbours: nominal masses 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. Four checks cover the rest — mass spectrometry for identity at about 818 Da, the CAS number on the label, net peptide content for quantity, and an LAL endotoxin result, since FDA flagged aggregation and peptide-related impurities specifically.

The Purity Index records GHRP-2 at 99.21 across 35 recency-weighted tests from 10 laboratories (verified August 2026), against a composite of 99.50 across 10,110 tests. Thirty-five 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.

GHRP-2 price data shows 9 shops in stock, a median of $4.60/mg and a low of $2.80/mg (verified August 2026). Those figures exclude shipping, taxes and customs, coupon codes, bulk tiers, multi-vial kits and account-gated pricing.

Method reading: how to verify peptide quality before you buy and mass spectrometry for peptides.

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 was discontinued. A separate formulation remained in Phase 2 for short stature, and only the diagnostic use survived to market.

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?

The only human trial found 7 of 10 GH-deficient children reporting increased appetite during the first six months of oral dosing, with no significant change in BMI standard deviation score over 12 months. The effect was transient and self-reported, in ten children.

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

Because the sixteen substances removed in April 2026 came off when their nominators withdrew the nominations. Nobody withdrew GHRP-2's, and nobody withdrew GHRP-6's. 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.

The trial that would settle this

The trial that would settle GHRP-2 recruits adults rather than children, since all therapeutic human data 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 µg/L across 135 subjects, and a documented commercial decision to stop developing it as a treatment. Every one of those is a real document, which is more than any sibling compound in the ghrelin-mimetic group 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 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.

Browse the growth hormone peptides category, or our complete peptide guide with 118 compounds (verified August 2026). For per-injection volume, use the peptide dosing calculator alongside the reconstitution calculator. Compare shops through independent lab tests and community-verified shop reviews.

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. 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.