What is the difference between GHRP-2 and GHRP-6?

Both are potent GH releasers, but GHRP-6 causes more pronounced appetite stimulation, while GHRP-2 causes slightly more cortisol release. GHRP-2 is often considered more potent for GH release overall.

How does GHRP-2 compare to Ipamorelin?

GHRP-2 is more potent for GH release but less selective—it also affects cortisol and prolactin. Ipamorelin is more selective with fewer side effects but may produce slightly less GH release.

Does GHRP-2 increase hunger?

Yes, GHRP-2 stimulates appetite through ghrelin receptor activation, though less dramatically than GHRP-6. This can be beneficial or problematic depending on the user's goals.

Fact-checked by the Peptide Authority Editorial Board · Last reviewed: 1 February 2026

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Hormonal & Endocrine•Updated 2026-02-01•5 min read

What Is GHRP-2? Benefits, Research & Safety

A potent growth hormone-releasing peptide that stimulates GH secretion through the ghrelin receptor, with additional effects on appetite and cortisol.

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Also known as:

Growth Hormone Releasing Peptide-2

Pralmorelin

KP-102

DAnimal/cell evidence onlyUK: Unlicensed (UK)WADA: Prohibited in sport

UK summary: Not a licensed UK medicine. Growth-hormone-releasing peptide. Prohibited at all times under WADA S2. Sometimes used in clinical research diagnostically (GH-stimulation testing), not as a therapy.

Quick Facts

Overview

GHRP-2 (Growth Hormone Releasing Peptide-2) is a synthetic hexapeptide that stimulates growth hormone release from the pituitary gland by activating the ghrelin/growth hormone secretagogue receptor (GHS-R). It is one of the most potent GHRPs in terms of GH release. Developed in the 1990s, GHRP-2 has been extensively studied and is approved in some countries (notably Japan, under the name Pralmorelin) as a diagnostic agent for growth hormone deficiency. It produces robust GH release but also affects other hormonal systems including cortisol, prolactin, and appetite-stimulating pathways. GHRP-2 is often combined with GHRH analogues like CJC-1295 or Sermorelin for synergistic effects. The combination works through different receptor mechanisms that amplify total GH release. While GHRP-2 is approved for diagnostic use in some countries, it is not approved for therapeutic use anywhere. It remains a research compound in most regions and is prohibited in competitive sports.

Evidence standards summary

GHRP-2 — evidence and risk at a glance

Twenty standard modules scored against the Peptide Authority evidence grading methodology. Missing modules indicate the field has not yet been characterised editorially — treat absences as uncertainty rather than reassurance.

01Evidence snapshot

DAnimal/cell evidence onlyOverall grade against our evidence grading methodology.

Not a licensed UK medicine. Growth-hormone-releasing peptide. Prohibited at all times under WADA S2. Sometimes used in clinical research diagnostically (GH-stimulation testing), not as a therapy.

02Human evidence grade

CLimited human evidenceStrength of evidence from published human trials.

03Preclinical evidence grade

BModerate human evidenceAnimal-model and in-vitro evidence quality.

04Regulatory status

UK: Not licensed for human use. Research compound only.
EU: Not approved for therapeutic use.
Notes: GHRP-2 is approved in Japan as a diagnostic agent (Pralmorelin). It is not approved therapeutically anywhere. Prohibited in sports by WADA.

05Approved medical uses

None in the UK or EU as a finished medicine. (Or: not yet documented; treat as absence rather than approval.)

06Unapproved / promotional claims

Restores youthful GH levels safely.
Effective treatment for sarcopenia or adult GH deficiency.
Undetectable by WADA testing.
Safe for daily long-term use.

07Common internet claims

Marketed as a cleaner alternative to HGH for body composition.
Sold by online retailers for stacking with CJC-1295.
Promoted by 'anti-ageing' clinics for off-label use.

08Claim vs evidence

Claim	Evidence	Human evidence?	Regulatory concern	Safer wording
“Used in NHS GH diagnostic testing — therefore safe”	C	Yes	High	GHRP-2 has a research / diagnostic history; that does not equate to a licensed therapy for healthy adults.
“Effective and safe long-term”	E	No	High	Long-term safety data in healthy adults is limited.
“Permitted for non-tested athletes”	E	No	High	Prohibited at all times under WADA S2; strict-liability rules apply regardless of testing schedule.

09Safety uncertainty score

High

Limited human safety data; meaningful uncertainty about rare or long-term effects.

10Known adverse signals

Cortisol and prolactin elevation (unlike Ipamorelin).
Water retention, joint pain, carpal tunnel symptoms (GH-axis effects).
Injection-site reactions.
Theoretical oncologic risk from sustained IGF-1 elevation.

11Drug-interaction uncertainty

High

Interaction picture sparse; meaningful uncertainty when combined with other medicines.

12Anti-doping status

WADA: Prohibited in sportWADA strict-liability framing applies.

13UK legal position

UK: Unlicensed (UK)

Not licensed for human use. Research compound only.

Read the full UK legal guide → Peptides and athletes (UK)

14EU legal position

Not approved for therapeutic use.

15What this page cannot tell you

Whether a UK-purchased vial contains GHRP-2 at the labelled concentration.
How sustained cortisol elevation affects metabolic and immune outcomes.
What the cancer risk profile is over years of off-label use.
Whether it triggers WADA detection — assume yes, prohibition is strict-liability.

16Last reviewed

Last reviewed: 1 February 2026

Next review due: 1 February 2027

Spotted an error or something out of date? Send a correction.

17Citation quality score

CLimited human evidenceQuality of the sources we cite, graded against the evidence grading methodology.

18Research gaps

Diagnostic-test use does not translate to licensed therapeutic indication.
Long-term outcome data in healthy adults absent.
Combination-stack safety with CJC-1295, Ipamorelin uncharacterised.
Cancer surveillance data unavailable.

19Safer alternatives / established care pathways

Endocrinologist review with ITT or GHRH-arginine testing if adult GH deficiency is clinically suspected.
Licensed recombinant HGH (Genotropin, Norditropin) under specialist supervision where genuine deficiency is confirmed.
Resistance training and protein-adequate nutrition for body-composition goals.

20Doctor discussion prompts

Questions to ask a qualified clinician

These are starter questions you can adapt for a GP, specialist, pharmacist, or anti-doping advisor. The aim is to help you have a better-informed conversation — not to replace one.

Is GHRP-2 a licensed UK medicine?
What's the WADA / UKAD position?
What licensed treatments exist for the underlying issue?

Discovery & History

GHRP-2 emerged from a research programme investigating growth hormone secretagogues in the 1980s and 1990s. The original growth hormone-releasing peptides were developed by Cyril Bowers and colleagues, who discovered that certain synthetic peptides could stimulate GH release independently of the natural GHRH pathway. GHRP-2 was identified as one of the most potent members of this peptide family. Structure-activity relationship studies helped optimise the sequence for maximal GH release. The discovery of the ghrelin receptor (GHS-R) in 1996 provided the molecular target for GHRPs. This receptor was later found to be the natural receptor for ghrelin, a gut hormone that stimulates hunger and GH release. GHRPs like GHRP-2 act as synthetic ghrelin mimetics. GHRP-2 was developed for clinical use in Japan under the name Pralmorelin, where it was approved as a diagnostic agent for GH deficiency. The peptide's potent and reliable GH-releasing effect made it useful for testing pituitary function. Research continues into GHRPs and their potential therapeutic applications beyond diagnostic use.

Mechanism of Action

GHRP-2 primarily works through the ghrelin receptor: **GHS-R Activation** GHRP-2 binds to and activates the growth hormone secretagogue receptor (GHS-R, ghrelin receptor) on pituitary somatotroph cells. This triggers intracellular calcium release and subsequent GH secretion. **Hypothalamic Effects** GHRP-2 also acts at the hypothalamic level, stimulating GHRH release and potentially inhibiting somatostatin. These central effects contribute to its GH-releasing action. **Cortisol and Prolactin Effects** Unlike the more selective Ipamorelin, GHRP-2 also stimulates cortisol and prolactin release. These effects are generally modest but distinguish GHRP-2 from more selective alternatives. **Appetite Stimulation** Through ghrelin receptor activation, GHRP-2 can stimulate appetite. This effect is less pronounced than with GHRP-6 but still notable. **Synergy with GHRH** GHRP-2 works synergistically with GHRH or GHRH analogues. The combination produces greater GH release than additive effects would predict, as the peptides work through complementary receptor systems.

Researched Benefits

Based on preclinical and clinical research findings:

1
Potent growth hormone release from the pituitary
2
Elevated IGF-1 levels
3
Potential improvements in body composition
4
Possible enhancement of recovery and tissue repair
5
Appetite stimulation (may benefit those needing to gain weight)
6
Synergistic effects with GHRH analogues

Claim vs Evidence

How popular claims about GHRP-2 stack up against the current research, graded using our public evidence grading methodology.

Claim	Evidence	Human evidence?	Regulatory concern	Safer wording
“Used in NHS GH diagnostic testing — therefore safe”	C	Yes	High	GHRP-2 has a research / diagnostic history; that does not equate to a licensed therapy for healthy adults.
“Effective and safe long-term”	E	No	High	Long-term safety data in healthy adults is limited.
“Permitted for non-tested athletes”	E	No	High	Prohibited at all times under WADA S2; strict-liability rules apply regardless of testing schedule.

Theoretical Dosing & Protocols

⚠️ Educational Only: The following information is derived from research literature and is not a prescription or recommendation. No standardised human dosing exists. Always consult a qualified healthcare professional.

Theoretical Dosage	100-300 mcg per dose
Frequency	2-3 times daily, typically before meals and at bedtime
Duration	Variable; often cycled
Notes	GHRP-2 is not approved for therapeutic use outside diagnostic applications. It causes more cortisol/prolactin release than Ipamorelin and more appetite stimulation. Any use should be under medical supervision.

Administration Routes

Routes studied in research settings (educational only):

Subcutaneous injection (most common)
Intravenous (diagnostic use)

Half-Life	Stability
Approximately 25-30 minutes	Lyophilised powder stable when properly stored; reconstituted solution should be refrigerated

Safety Profile & Known Risks

Commonly Reported Side Effects

Increased appetite
Water retention
Injection site reactions
Flushing
Tingling or numbness
Transient cortisol elevation

Rare Risks & Concerns

Prolonged effects on cortisol with chronic use
Potential effects on glucose metabolism
Unknown long-term effects
Theoretical concerns with tumour growth

Contraindications

Active malignancy
Pregnancy and breastfeeding
Diabetes (monitor closely)
Conditions exacerbated by cortisol elevation

UK & EU Regulatory Context

🇬🇧 United Kingdom

Not licensed for human use. Research compound only.

🇪🇺 European Union

Not approved for therapeutic use.

GHRP-2 is approved in Japan as a diagnostic agent (Pralmorelin). It is not approved therapeutically anywhere. Prohibited in sports by WADA.

Clinical Studies Summary

Effects of GHRP-2 and Cysteamine Administration on Growth Performance, Somatotropic Axis Hormone and Muscle Protein Deposition in Yaks (Bos grunniens) with Growth Retardation.

Growth retardation in yaks was primarily due to somatotropic axis hormones secretion deficiency. Both GHRP-2 and CS administration can accelerate growth performance and GH, IGF-1 secretion in yaks with growth retardation. GHRP-2 enhanced muscle protein deposition mainly by up-regulated the protein synthesis pathways, whereas CS worked mainly by down-regulated the ubiquitin-proteasome pathway.

PLoS One. 2016View on PubMed

Determinants of GH-releasing hormone and GH-releasing peptide synergy in men.

002). In conclusion, a paradigm examining GHRH-GHRP synergy under a sex steroid clamp reveals highly selective control of basal, pulsatile, and synergistic peptide-driven GH secretion by AVF, E(2), and IGF-I in healthy men.

Am J Physiol Endocrinol Metab. 2009View on PubMed

The combined administration of GH-releasing peptide-2 (GHRP-2), TRH and GnRH to men with prolonged critical illness evokes superior endocrine and metabolic effects compared to treatment with GHRP-2 alone.

Coadministration of GHRP-2, TRH and GnRH reactivated the GH, TSH and LH axes in prolonged critically ill men and evoked beneficial metabolic effects which were absent with GHRP-2 infusion alone and only partially present with GHRP-2 + TRH. These data underline the importance of correcting the multiple hormonal deficits in patients with prolonged critical illness to counteract the hypercatabolic state.

Clin Endocrinol (Oxf). 2002View on PubMed

Tyr-Ala-Hexarelin, a synthetic octapeptide, possesses the same endocrine activities of Hexarelin and GHRP-2 in humans.

In conclusion, the present results demonstrate that in humans Tyr-Ala-HEX is a GH secretagogue as potent as HEX and GHRP-2, two GHRP-6 superanalogs. Tyr-Ala-HEX also shares with HEX and GHRP-2 the same PRL- ACTH- and cortisol-releasing activity.

J Endocrinol Invest. 1999View on PubMed

Synergy of L-arginine and GHRP-2 stimulation of growth hormone in men and women: modulation by exercise.

Exercise potentiated the individual stimulatory actions of A and G, while blunting the relative magnitude of the synergistic (supra-additive) interaction observed at rest.

Am J Physiol Regul Integr Comp Physiol. 2000View on PubMed

Treatment effects of intranasal growth hormone releasing peptide-2 in children with short stature.

GHBP concentrations rose significantly, from 439 +/- 63 pmol/l to 688 +/- 48 pmol/l. In this study, intranasal GHRP-2 administration was well tolerated, and produced a modest but significant increase in growth velocity.

J Endocrinol. 1997View on PubMed

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Frequently Asked Questions

Questions to ask a qualified clinician about GHRP-2