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GH-axis

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GH-releasing hexapeptide (GHRP)

GHRP-2

Also known as: Pralmorelin, KP-102, D-Ala-D-2-Naphthylalanine-Ala-Trp-D-Phe-Lys-NH2

GHRP with reliable acute GH release (Tier 2) and a profile between ipamorelin (cleaner) and GHRP-6 (more appetite). Approved in Japan as a diagnostic stim test for GH deficiency under the name pralmorelin.

Reviewed 2026-05-05

What it does

GHRP-2 (pralmorelin) is a synthetic 6-amino-acid ghrelin receptor agonist that has the most concrete regulatory footprint of the GHRP family — Japan approved it as a diagnostic stimulation test for adult GH deficiency, providing a body of human pharmacology data that the rest of the GHRP class lacks. Clinically it slots between ipamorelin (cleaner, more selective) and GHRP-6 (older, more appetite-stimulating): meaningful but smaller appetite stimulation than GHRP-6, with cortisol and prolactin spikes intermediate between the two. As with the rest of the GHRP class, the gap between acute biochemical GH release and sustained body-composition outcomes in healthy adults is wide and not bridged by RCT-quality evidence.

Used for

Dose

Starting
100 mcg · 1–3× daily
Common
200 mcg · 1–3× daily
Upper
300 mcg · 1–3× daily
When
BedtimeGH secretagogue — same window as CJC + Ipa. Empty stomach. Bedtime aligns with the natural GH pulse. Diagnostic-pharmacology dosing differs (clinic-controlled per protocol).
Site
subcutaneous

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⚠ Caution

  • Active malignancy (theoretical concern from GH/IGF-1 elevation)
  • Uncontrolled diabetes (GH spikes worsen insulin resistance)
  • Pregnancy and breastfeeding
  • Adolescents with open growth plates (use only under endocrinology supervision)
  • Significant baseline cortisol elevation (Cushing's, chronic prednisone)
  • Known hypersensitivity to peptide formulations

Your stack

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Use this peptide

Reconstitution & storage

Lyophilized powder reconstituted with bacteriostatic water. A 5 mg vial in 2.5 mL BAC water = 2 mg/mL, making a 100 mcg dose = 5 units on a U-100 syringe. Use the Juno calculator for vial-specific math.

Storage. Lyophilized: refrigerate 2–8 °C. Reconstituted: refrigerate 2–8 °C, use within 30 days.

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Monitoring & questions

Reported side effects
  • Mild-to-moderate appetite stimulation (less than GHRP-6, more than ipamorelin)
  • Cortisol and prolactin elevation (intermediate between ipamorelin and GHRP-6)
  • Water retention, mild puffiness
  • Lethargy or transient flushing post-injection
  • Reduced glucose tolerance with sustained use
  • Numbness or tingling (rare; consistent with GH-excess effects with chronic use)
Biomarkers Juno tracks

Reference

How it works

Agonist at the growth hormone secretagogue receptor (GHSR-1a) at the pituitary and hypothalamus. Stimulates pulsatile GH release, synergistic with GHRH analogs (CJC-1295, sermorelin). Some ghrelin-pathway hypothalamic activity drives modest appetite increase. Like the rest of the class, prone to receptor desensitization with sustained continuous dosing.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Stimulation of endogenous GH release

Tier 2high confidence

Multiple human pharmacology studies (Bowers 1990s, Aimaretti 1998) and the Japanese diagnostic-test literature consistently characterize acute GH release at 100-mcg doses in adults. Tier 2 because the evidence base is biochemical and short-duration.

Aimaretti G et al. 1998Chapman IM et al. 1996

Diagnosis of adult growth hormone deficiency

Tier 1high confidence

Approved in Japan as a single-dose IV stimulation test (pralmorelin/GHRP-2) for adult GH deficiency, validated against insulin-tolerance test and arginine-GHRH against pituitary-disease populations. Indication is diagnostic, not therapeutic.

Chihara K et al. 2007

Body composition / fat loss / muscle gain

Tier 3high confidence

Recreational use is widespread but not directly studied at clinical-outcome level in healthy adults. Generalizing from acute GH release to sustained body-composition change is mechanism-as-evidence reasoning.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Appetite stimulation / mild cachexia adjunct

Tier 3medium confidence

Ghrelin-pathway activity reliably increases appetite acutely in human studies, but smaller effect size than GHRP-6. No completed cachexia outcome trial.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (3)
  1. [1]
    Comparison between insulin-induced hypoglycemia and growth hormone (GH)-releasing hormone + arginine as provocative tests for the diagnosis of GH deficiency in adults
    Aimaretti G, Corneli G, Razzore P, et al. · Journal of Clinical Endocrinology and Metabolism · 1998 · PMID 9701679
    Validation of GHRP-2 / GHRP-2+GHRH as a stimulation test for GH deficiency; anchor for Tier 1 diagnostic indication.
    View source
  2. [2]
    Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects
    Chapman IM, Bach MA, Van Cauter E, et al. · Journal of Clinical Endocrinology and Metabolism · 1996 · PMID 8675588
    Cross-class context for sustained GHSR-1a agonist effects on GH/IGF-1 axis in elderly adults — informs the body-composition tier framing.
    View source
  3. [3]
    A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency
    Chihara K, Shimatsu A, Hizuka N, et al. · European Journal of Endocrinology · 2007 · PMID 17284627
    Multi-center Japanese study establishing the GHRP-2 stim test cutoffs used clinically. Anchor for the diagnostic indication.
    View source