APPROVED IN JAPAN · NOT FDA-APPROVED

GHRP-2 (Pralmorelin)

Older GHRP · largely replaced by Ipamorelin in modern stacks

An older growth-hormone-releasing peptide. Approved in Japan as a diagnostic tool. Stronger GH pulse than Ipamorelin, but with collateral cortisol and prolactin elevation. That collateral profile is the reason most modern protocols use Ipamorelin instead.

The 30-second read

GHRP-2 (also called Pralmorelin or KP-102) is a small synthetic peptide that activates the ghrelin receptor to trigger GH release from the pituitary, the same mechanism as Ipamorelin, but older and less selective. Approved in Japan in 2007 as a single-dose diagnostic test for GH deficiency. Never FDA-approved. Produces a larger GH pulse than Ipamorelin from the same dose, but also raises cortisol, prolactin, and ACTH, the side-effect collateral that pushed researchers to develop the cleaner Ipamorelin. Still used in some research-peptide protocols, often paired with a GHRH analog like Sermorelin or CJC-1295. On the FDA's Category 2 list as of September 2023.

Why this peptide is on people's radar

GHRP-2 sits in an interesting historical position. It was developed in the 1990s and was one of the first synthetic ghrelin-receptor agonists to demonstrate reliable GH release in humans. It got far enough through clinical development that Japan's regulatory authority approved it in 2007 as a single-dose diagnostic test for GH deficiency, a real, formal regulatory approval, just for a narrow indication. The U.S. development path didn't reach approval, partly because direct GH replacement (somatropin) was already established for the indications GHRP-2 might have served, and partly because the cleaner Ipamorelin emerged from Novo Nordisk's research around the same time.

Today, GHRP-2 is used primarily in research-peptide and longevity-clinic protocols, often paired with a GHRH analog (Sermorelin or CJC-1295) for synergistic GH release. The pitch versus Ipamorelin: GHRP-2 produces a stronger GH pulse from the same molar dose. The trade-off versus Ipamorelin: GHRP-2 also raises cortisol, prolactin, and ACTH, which is why modern protocols typically prefer Ipamorelin's cleaner profile. Some users specifically want the appetite-stimulating effect of GHRP-2 (it activates ghrelin signaling more strongly than Ipamorelin), particularly in the context of muscle-gain or weight-gain protocols.

It's also worth knowing that GHRP-2 was on the FDA's Category 2 list as of September 2023, alongside GHRP-6, Sermorelin, and several other GH-axis peptides. The April 2026 FDA advisory-panel review of compounded peptides included GHRP-2 in scope.

What people are usually trying to do with it

People exploring GHRP-2 (almost always as part of a stack) are usually focused on:

A stronger GH pulse than Ipamorelin produces
Appetite stimulation (the ghrelin-pathway side effect that's a feature, not a bug, in some protocols)
Diagnostic GH stimulation testing (the Japan-approved use)
Better sleep and recovery from a more pronounced GH pulse
An older, more-studied option than the newer GHRPs
Synergistic combination with a GHRH analog (Sermorelin or CJC-1295)

What the science actually shows

GHRP-2 has more clinical-trial data than most research peptides on this site. Plain-English summary:

GH stimulation diagnostic (Japan-approved use)

The data supporting Japan's 2007 approval established that GHRP-2 reliably stimulates pituitary GH release at standardized doses, making it a valid diagnostic tool for GH deficiency.1

GH and IGF-1 elevation in adults

Studies in healthy adults and in adults with low IGF-1 show reliable GH pulses from GHRP-2 administration, with measurable IGF-1 elevation over weeks of repeated dosing.2

Cortisol, prolactin, and ACTH elevation

Multiple studies confirm that GHRP-2, unlike Ipamorelin, also stimulates cortisol, prolactin, and ACTH release. Effect sizes are typically modest at standard doses but clinically noticeable and the basis for Ipamorelin's preferred status in most modern protocols.3

Synergy with GHRH analogs

GHRP-2 combined with a GHRH analog (Sermorelin, CJC-1295) produces synergistic GH release that exceeds either alone, the same additive principle behind the CJC-1295/Ipamorelin combo.4

What hasn't been demonstrated

FDA approval. Long-term safety with chronic adult anti-aging use. Direct head-to-head clinical-outcome comparisons with Ipamorelin. That GHRP-2's larger GH pulse translates into meaningfully better real-world outcomes (sleep, body composition, recovery) than Ipamorelin produces.

The honest read

What's solid:

GHRP-2 is one of the more rigorously studied research peptides in this space, with Japanese regulatory approval for a defined indication and decades of clinical data. The GH-release mechanism works as advertised. Used as a diagnostic tool in defined clinical contexts, it's a legitimate and well-characterized tool.

What's still being worked out:

Whether the GH pulse produced by GHRP-2 translates into the downstream outcomes people actually want, sleep, body composition, recovery, anti-aging effects. The answer is probably the same as for Ipamorelin and CJC-1295: modestly, in some users, with substantial individual variability. Direct head-to-head comparisons of clinical outcomes (not just GH levels) haven't been done.

What's hyped beyond the evidence:

"Stronger than Ipamorelin therefore better" framings. The larger GH pulse comes with more cortisol, prolactin, and ACTH elevation, that's why Ipamorelin became the preferred option, not because GHRP-2 is somehow inadequate. Pick GHRP-2 over Ipamorelin if you have a specific reason (appetite stimulation, larger pulse acceptable for the goal). Don't pick it just because the GH numbers look bigger on paper.

Things to know if you're looking into it

Almost always stacked: like Ipamorelin, GHRP-2 is most commonly used paired with a GHRH analog (Sermorelin or CJC-1295 No-DAC). The synergy logic is identical.
How it's used: a small subcutaneous injection at night before bed, on an empty stomach. Some research-community protocols use 2–3x daily dosing.
Cortisol and prolactin caveat: the main reason Ipamorelin became preferred. If you're tracking cortisol-related symptoms (anxiety, sleep disruption, weight pattern) or prolactin-related ones (mood, libido), GHRP-2 is a less clean choice than Ipamorelin.
Appetite stimulation: can be intense, especially with the first dose. Sometimes used intentionally for people trying to gain weight or muscle mass; an unwanted side effect for people focused on weight loss or weight maintenance.
Athlete bans: GHRP-2 is on the World Anti-Doping Agency banned list. Competitive athletes will test positive.
Regulatory status: Approved in Japan for diagnostic use only. Not FDA-approved. On the FDA's Category 2 list as of September 2023.
Specific dosing protocols, mechanism, and the full reference list: all in the "Want to go deeper?" section below.

What people often ask

How is GHRP-2 different from Ipamorelin?

Same general mechanism (both activate the ghrelin receptor to trigger GH release). GHRP-2 is older and produces a larger GH pulse from the same dose, but it also raises cortisol, prolactin, and appetite. Ipamorelin is newer and selective enough to produce GH release without those side-channel effects, which is why most modern protocols use Ipamorelin.

Is GHRP-2 stronger than Ipamorelin?

For raw GH release, yes, at the same molar dose, GHRP-2 produces a bigger pulse. Whether that translates into better real-world outcomes is less clear, and the trade-off in cortisol/prolactin elevation is real.

Why does it stimulate appetite?

GHRP-2 is a more potent ghrelin-receptor agonist than Ipamorelin. Ghrelin is the body's "hunger hormone", when GHRP-2 activates the receptor, the appetite signal goes along with the GH-release signal. Ipamorelin is selective enough to mostly trigger GH release without the appetite effect.

Is it FDA-approved?

No. Approved in Japan in 2007 as Pralmorelin / GHRP Kaken for single-dose diagnostic GH stimulation testing. Not FDA-approved in the U.S. On the FDA's Category 2 list as of September 2023, restricting compounding-pharmacy access.

Will it raise my cortisol?

Yes, modestly. The effect is dose-dependent and typically clinically noticeable but not extreme at standard doses. Anyone with cortisol-related health concerns (chronic stress, sleep issues from cortisol patterns, certain mood concerns) should probably start with Ipamorelin instead.

Should I use GHRP-2 or Ipamorelin?

Ipamorelin is the default for most people because of the cleaner side-effect profile. GHRP-2 has a place if you specifically want a stronger GH pulse and aren't bothered by the cortisol/prolactin effects, or if you want the appetite-stimulating effect. Talk to a clinician.

Will I test positive on a drug test?

Yes. GHRP-2 is on the WADA banned list. Competitive athletes will test positive.

FDA and regulatory status

Status as of May 5, 2026: Not FDA-approved in the United States. Approved in Japan in 2007 (as Pralmorelin / GHRP Kaken) for single-dose diagnostic testing of GH deficiency. On the FDA's Category 2 list as of September 2023, restricting compounding-pharmacy access. The April 2026 FDA advisory-committee review of compounded peptides included GHRP-2 in scope. Status updates land here when they happen.

Want to go deeper? Mechanism, half-life, dosing, side-effect profile, and references.

Background

GHRP-2 (Pralmorelin) is a synthetic hexapeptide growth-hormone secretagogue developed in the 1990s. Chemical name D-Ala-D-βNal-Ala-Trp-D-Phe-Lys-NH₂. Approved in Japan in 2007 for diagnostic use in suspected GH deficiency. Never approved by the FDA. Sold internationally as a research peptide and used in compounded preparations through licensed pharmacies until the September 2023 FDA Category 2 listing restricted that pathway.

Mechanism of action

GHS-R / ghrelin receptor agonism

GHRP-2 binds the GHS-R1a receptor on pituitary somatotrophs, mimicking the natural hormone ghrelin and triggering pulsatile GH release. The mechanism is identical to Ipamorelin's mechanism at this receptor.

Less selective than Ipamorelin

Where the two peptides differ is at adjacent pathways. GHRP-2 also activates pathways that elevate cortisol (via ACTH) and prolactin in addition to GH. At standard doses these elevations are modest but measurable. Ipamorelin was specifically designed to preserve GH-release activity while minimizing the cortisol/prolactin effects, which is why it became the dominant GHRP in modern protocols.

Synergy with GHRH analogs

Combining GHRP-2 with a GHRH analog (Sermorelin, CJC-1295) produces a synergistic GH pulse 2–3 times larger than either alone, the same principle behind CJC-1295 / Ipamorelin combinations.

Half-life

Plasma half-life is approximately 15–60 minutes depending on the study and route of administration. The GH-pulse window after dosing is roughly 1 to 2 hours.

Commonly studied dosing protocols

These are not recommendations. Always consult a licensed healthcare provider before any clinical decision.

Diagnostic testing (Japan-approved): single subcutaneous or IV dose at standardized weight-based mcg/kg, with serial GH measurements over 60–120 minutes.

Subcutaneous (research-community range): 100 to 300 mcg per dose, once nightly before bed on an empty stomach. Some protocols use 2–3x daily dosing.

Stacked with a GHRH analog: commonly paired with Sermorelin 100–300 mcg or CJC-1295 (No DAC) 100 mcg.

Treatment duration: typical research-community cycles are 8 to 12 weeks. Long-term continuous use in healthy adults has not been formally characterized.

Side effects and safety profile

Reported in clinical trials and research-community use:

Mild flushing or warmth shortly after injection (common, transient)
Injection-site redness or tenderness (common, mild)
Increased appetite, pronounced (common; often the most-noticed side effect)
Brief lightheadedness (uncommon)
Mild fluid retention (uncommon)
Modest cortisol and prolactin elevation (dose-dependent)
Mood or sleep effects related to cortisol/prolactin shifts (variable)

Theoretical concerns: GH/IGF-1 elevation interacts theoretically with cancer biology, avoid in active malignancy. Cautious use in diabetes, sleep apnea, carpal-tunnel-prone individuals, and people with cortisol-axis sensitivity.

References

Bowers CY, Reynolds GA, Durham D, et al. (1990). "Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone." J Clin Endocrinol Metab, 70(4), 975–982. PubMed
Pihoker C, Badger TM, Reynolds GA, Bowers CY. (1997). "Treatment effects of intranasal growth hormone releasing peptide-2 in children with short stature." J Endocrinol, 155(1), 79–86. PubMed
Sigalos JT, Pastuszak AW. (2018). "The safety and efficacy of growth hormone secretagogues." Sex Med Rev, 6(1), 45–53. PubMed
Alba M, Fintini D, Bowers CY, et al. (2005). "Effects of long-term treatment with GHRP-2 in different forms of GH deficiency." J Endocrinol Invest, 28(5 Suppl), 178–183. PubMed
U.S. Food and Drug Administration. (2023). "Pharmacy Compounding Guidance. FDA Category 2 List." FDA.gov

For educational and research purposes only. This is not medical advice. GHRP-2 is approved in Japan for diagnostic use only and is not FDA-approved. On the FDA's Category 2 list as of September 2023. Consult a licensed healthcare provider before considering any peptide. PeptideLibraryHub is independent and does not sell peptides or accept money from anyone who does.