GHRP-2 Is an Approved Drug in Japan, and the Approval Covers One Injection

01What it is

GHRP-2 is a lab built chain of six amino acids, an analogue of GHRP-6 rather than a form of ghrelin, and it circulates under at least six names: GHRP-2, pralmorelin, which is the international nonproprietary name, KP-102 with its formulation codes KP-102D and KP-102LN, GPA-748, and the Japanese trade name GHRP Kaken 100 (PMID 15230633). A secretagogue, the word this class gets filed under, makes a gland let go of a hormone rather than being that hormone itself.

02What the trials found

Arvat and colleagues, 1997, gave 1 and 2 mcg/kg intravenously to six normal young adults and 2 mcg/kg to six elderly subjects, and prolactin, ACTH and cortisol rose along with growth hormone, the authors saying plainly that the compound is not fully specific (PMID 9285939).

The best replicated effect in healthy adults is appetite: seven lean healthy men on a 270 minute subcutaneous infusion at 1 mcg/kg/h ate 35.9 percent more at a buffet meal than on saline (PMID 15699539), and 19 subjects, ten lean and nine obese, on double blind subcutaneous infusions ate 33.5 percent more at 1 mcg/kg/h and 10.2 percent more at 0.1 mcg/kg/h than on placebo (PMID 16861611).

03The growth signal that only moved under a pump

Growth hormone itself arrives in pulses and clears quickly. The number that would show something lasting is IGF-1, insulin like growth factor 1, the slower growth signal that follows along behind it.

Nijland used the community's dose, route, frequency and demographic, which makes it the most relevant human study there is. Nine healthy young men, 100 mcg subcutaneously once daily for five days. Peak growth hormone fell from a mean of 83 mcg/L on day 1 to 59 on day 3 and 51 on day 5, and mean serum IGF-I did not move at all, sitting at 22, 25, 23, 25, 23 and 24 nmol/L on days 1 to 6 (PMID 9820615). That flat IGF-1 held over far longer runs in children, across eight months of escalating subcutaneous doses from 0.3 to 3.0 mcg/kg/day in six growth hormone deficient children who grew faster all the same (PMID 9661608), and over 18 to 24 months of intranasal dosing in children with short stature (PMID 9390009).

Now the exception, and the study most often reached for when somebody quotes a rise in IGF-1. Five men and five women, older, with decreased growth hormone secretion and low IGF-1, received 1 mcg/kg/h by continuous subcutaneous infusion for 30 days, and pulsatile growth hormone and serum IGF-1 were both up after 24 hours and both stayed up for the full 30 days (PMID 11322505) That same paper also reports acute bolus doses of 0.1, 1 and 10 mcg/kg, described in its abstract as intravenous except for the 10 mcg/kg dose, which is the only one it calls subcutaneous..

A pump is not an injection. Picture a bath with the plug out: a trickle left running all month holds the level, and a few hard bursts a day drain away in between. That picture is mine, not a published mechanism, and I found no paper stating the pattern explicitly. The intensive care work sits on the infusion side of it: twenty-six critically ill adults averaging 63 years in a randomised crossover, twenty-two given GHRP-2 as a 1 mcg/kg intravenous bolus then 1 mcg/kg/h intravenously for 21 hours, with serum IGF-I up 61 percent within 24 hours (PMID 9024260).

04The citation that sent me back to the ipamorelin entry

One community dosing guide credits the desensitisation finding to "Raun et al., Growth Horm IGF Res (1998)" while linking PMID 9820615, which is Nijland in the European Journal of Endocrinology. Raun 1998 is a different paper, and it is the ipamorelin swine study, so a GHRP-2 cycling protocol is being justified by a citation that, read literally, points at a pig experiment on a different molecule. The ipamorelin entry said that pig study recorded nothing for GHRP-2. The abstract says otherwise: both GHRP-6 and GHRP-2 raised ACTH and cortisol in those pigs, ipamorelin did not, and that is precisely the axis on which ipamorelin was found to differ (PMID 9849822).

05How it compares

GHRP-2, GHRP-6, ipamorelin and hexarelin get sold as versions of one another. Their records are not.

Hexarelin is the only row where anyone measured a body over months, and nothing in it changed. Everywhere else the outcome is a hormone level, or a hospital endpoint nobody buys the compound for.

06Where the dose came from

GHRP-2 is the only growth hormone secretagogue in this reference with an approved medicinal product anywhere that I could find. In Japan it is sold as GHRP Kaken 100 for injection, generic name pralmorelin hydrochloride, by Kaken Pharmaceutical, indicated for the diagnosis of growth hormone secretion deficiency, marketed since February 2005 with the label last revised in July 2022. The approved dose is one slow intravenous injection given fasting, 100 mcg from age 18, and 2 mcg/kg capped at 100 mcg from age 4 to under 18.

The convention that circulates differs in route and frequency: 100 to 300 mcg per injection, subcutaneously, one to three times daily, most commonly 200 mcg, taken fasted and cycled. Subcutaneously means under the skin rather than into a vein, which is the difference between the approved product and the habit. I could not establish any derivation for it, beyond noting that it lands on the same 100 mcg as the Japanese diagnostic dose and the Nijland protocol, with nobody appearing to have reasoned from either.

07What could go wrong

The label lists real adverse reactions with frequencies attached. I opened the current package insert and read the table myself, because two automated readings of it had disagreed about which reaction sits in which band.

Three things sit at 5 percent or more: borborygmus, a raised white cell count, and a sensation of heat at 16.0 percent. Borborygmus is the noise a stomach makes when it rumbles. At 0.1 to under 5 percent, hypotension, nausea, gastric discomfort, abdominal distension, somnolence, rhinorrhoea, sweating, thirst, cold sweat, malaise, unsteadiness, and a sensation of hunger.

Note which one hunger is. It is a sensation of hunger rather than a decrease in appetite, and it is a quantified reaction rather than an unquantified one. All of it is one intravenous dose under supervision, not a record of a repeated subcutaneous habit.

The other things that could go wrong are not medical. WADA names it explicitly and by both names under S2.2.4 of the 2026 Prohibited List effective 1 January 2026, prohibited at all times and non-Specified, the tier carrying a four year default sanction. In the United States it is not approved and it is not on the 503A bulks list, sitting in Category 3, nominated without adequate support, which means FDA never evaluated it at all. As for what is in the vial, the Cologne analysts who found an extra glycine on black market ipamorelin found it on GHRP-2 too (PMID 29864719).

08What nobody knows

Body composition. Across roughly 250 PubMed records I found no human trial with body composition, lean mass, fat mass, muscle size, strength, athletic performance, recovery or injury healing as a measured outcome. The one study aimed at the people who actually buy this is a retrospective chart review of men on testosterone therapy given GHRP-2 alongside GHRP-6 and sermorelin, which reported IGF-1 rising and measured only serum hormones (PMID 28830317). A chart review looks backwards at notes already written, and three compounds went in at once.

I found no registered study of GHRP-2 anywhere on ClinicalTrials.gov either, and no published carcinogenicity, genotoxicity or repeat dose toxicology study. The longest nonclinical dosing I found is six weeks, 10 mcg subcutaneously twice a day in GHRH knockout mice, where the peptide failed to restore growth and worsened the body composition abnormalities of growth hormone deficiency (PMID 15985453). Those were mice bred without growth hormone releasing hormone, and the result still ran the wrong way.

09My take

The label is what makes this compound different, and it argues against the sales pitch rather than for it.

The IGF-1 split is the finding I would want a buyer to sit with. Dosed intermittently, it did not move over five days of injections in healthy men, over eight months of injections in deficient children, or over 18 to 24 months through the nose. It moved under a 30 day pump and under an intravenous drip in intensive care. Nobody runs a pump.

If you have run GHRP-2, I want to know whether your appetite changed on it and how quickly, because that is the effect the trials found twice and the label prints, and it is the one nobody sells it on.

Frequently asked

Is GHRP-2 approved anywhere?+

Yes, in Japan. The approved use is a single slow injection into a vein, given fasting and under supervision, as a test of whether the pituitary can release growth hormone.

Does GHRP-2 raise IGF-1?+

Given as an injection, serum IGF-1 did not move over five days in nine healthy young men, over eight months in six growth hormone deficient children, or over 18 to 24 months of dosing through the nose in children with short stature. It did rise and stay risen under a continuous infusion under the skin for 30 days in ten older adults with reduced output, and it rose 61 percent within 24 hours under a drip into a vein in critically ill adults.

What does GHRP-2 do to appetite?+

Seven lean healthy men on an infusion under the skin ate 35.9 percent more at a buffet meal than on salt water, and in a second study of 19 subjects, ten lean and nine obese, food intake rose 33.5 percent at the higher infusion rate and 10.2 percent at the lower one.

Is GHRP-2 the same as GHRP-6, ipamorelin or hexarelin?+

No. GHRP-2 is an analogue of GHRP-6 rather than a form of ghrelin, and it is the only one of the four with an approved product anywhere that I could find.

Where does the dose people actually use come from?+

I could not establish any derivation for it. What circulates is a habit rather than a protocol.

Is GHRP-2 safe?+

The honest position is that the only safety data with numbers attached describes a single injection into a vein, given under supervision as a test. None of that describes repeated injections under the skin over weeks, which is what circulates.

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This content is for educational and informational purposes only and is not medical advice. Peptides discussed are research compounds and may not be approved for human use. Nothing here should be used to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before starting any peptide, supplement, or protocol. Individual responses vary. Do not self-administer compounds without proper medical supervision.