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GHRP-2

peptide · headlineResearch use only

Binds to ghrelin receptor (GHS-R1a) on pituitary somatotrophs

Overview

GHRP-2 is a potent growth hormone secretagogue that stimulates the natural release of GH via the ghrelin receptor. It has been evaluated in preclinical and limited human research for its endocrine and appetite-regulating effects. It supports GH-IGF-1 axis activation with minimal prolactin or cortisol impact at moderate doses.

How it works

  • Binds to ghrelin receptor (GHS-R1a) on pituitary somatotrophs
  • Promotes endogenous pulsatile GH secretion
  • Enhances IGF-1 production downstream of GH
  • Activates hunger and energy regulation via hypothalamic stimulation

Dosing

Standard dose: 100–300 mcg SQ 1–2x daily. Best administered 30 min before meals or at bedtime to coincide with natural GH pulse patterns. Use in 6–12 week cycles, followed by 2–4 week break to reset receptor sensitivity. Often stacked with CJC-1295 (no DAC) or GHRP-6.

Subcutaneous (SQ)200 mcg standardrange 100–300 mcg· 1-2 times daily (pre-meal or pre-sleep)

Caution: In animal models, GHRP-2 is often used at 100–200 μg/kg via subcutaneous injection. Limited human studies have used 100–300 μg doses for investigational purposes only. It is not FDA-approved for clinical use.

Cycling

  • Use 1–2x daily for 6–12 weeks, followed by 2–4 week break to reset receptor sensitivity. Combine with GH-releasing peptides like CJC-1295 for best results.

Side effects

Common
  • Transient appetite increase (ghrelin receptor activation)
  • Transient cortisol and prolactin elevation
  • Receptor desensitization (tachyphylaxis) with continuous daily use; cycling recommended

Stacking & combinations

With

CJC-1295

Benefit

Combines well with CJC-1295 to potentiate GH and IGF-1 release

With

IGF-1 DES

Benefit

Enhances muscle recovery and anabolic response with IGF-1 LR3

Lifestyle support

Diet

Protein-forward diet.

Sleep

Prioritize sleep and stress management.

Timing

Inject on empty stomach (2–3 hours post-meal).

Exercise

Resistance and aerobic activity.

Research studies

Studies summarized for educational purposes only. Inclusion does not imply human use; referenced research was conducted in vitro, in animal models, or in regulated clinical trials.

Research study

A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency

Chihara K, et al. Eur J Endocrinol. 2007;157(1):19-27. View source ↗

Scientific findings

In a multicenter study of 77 healthy controls and 58 adult GH-deficiency (GHD) patients, a single subcutaneous injection of GHRP-2 elicited a peak GH response within 60 minutes in all subjects. Peak GH was markedly lower in GHD patients (1.36 +/- 2.60 ug/l) than in healthy controls (84.6 +/- 60.9 ug/l). A peak GH cutoff of 15 ug/l corresponded to the insulin tolerance test threshold and diagnosed severe GHD with high sensitivity and specificity, with favorable reproducibility.

Plain English

Researchers tested whether a single injection of GHRP-2 could reliably identify adults who lack growth hormone, as a simpler and safer alternative to the standard insulin tolerance test. People with growth hormone deficiency produced far less growth hormone after the injection than healthy people, and a clear cutoff accurately separated the two groups.

Research study

Diagnostic usefulness of the growth hormone-releasing peptide-2 test as a substitute for the insulin tolerance test in hypopituitarism

Kageyama K, et al. Endocr J. 2008;55(4):777-783. View source ↗

Scientific findings

This study evaluated whether the GHRP-2 provocative test could substitute for the insulin tolerance test (ITT) in assessing the hypothalamic-pituitary axis in hypopituitarism. Patients showing a significant ACTH response to the ITT also responded to GHRP-2, while ITT non-responders likewise failed to respond, indicating concordance. The authors concluded GHRP-2 testing may be a useful alternative for identifying secondary adrenal insufficiency, avoiding the risks of insulin-induced hypoglycemia.

Plain English

The insulin tolerance test is the traditional way to check pituitary function but can cause dangerously low blood sugar. This study found the GHRP-2 test agreed with the insulin test for detecting pituitary-related hormone problems, suggesting it could be a safer stand-in.

Research study

Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men

Laferrere B, et al. J Clin Endocrinol Metab. 2005;90(2):611-614. View source ↗

Scientific findings

Seven lean healthy men received a subcutaneous infusion of GHRP-2 (1 ug/kg/h) or saline before an ad libitum buffet meal in a crossover design. GHRP-2 increased food intake by approximately 35-36% versus saline, with unchanged macronutrient composition, while GH rose significantly. The findings show GHRP-2, a synthetic ghrelin-receptor agonist, stimulates appetite in humans much like ghrelin.

Plain English

Because GHRP-2 acts on the same receptor as the hunger hormone ghrelin, researchers tested whether it makes people eat more. Healthy men given GHRP-2 ate roughly a third more at a buffet than on placebo, confirming it boosts appetite in people, not just growth hormone.

Verified citations

2 · PubMed-checked

Reconstitution calculator

Subcutaneous (SQ)
Draw to4 units

= 0.04 mL on a U-100 insulin syringe

Concentration5 mg/mL
Doses / vial50

Assumes a U-100 insulin syringe (100 units = 1 mL). This is a preparation aid, not a protocol — dose and route are the prescriber's decision. Refrigerate at 2–8 °C (35.6–46.4 °F); use within 28 days. Avoid freeze–thaw; aliquot if needed

Chemistry & PK

Sequence
D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2
Half Life
Approx. 30 minutes
Degradation
Metabolized hepatically and renally
Molecular Weight
817
Molecular Formula
C45H55N9O6
Tissue Specificity
Targets pituitary gland and hypothalamus

Bioavailability

Oral
Poor due to enzymatic degradation and low systemic absorption
Subq
High for peptide-based GH stimulation; commonly used via this route

Storage & handling

Lyophilized

freeze at −20 °C (−4 °F); after reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F) and use within 28 days

Reconstituted

Refrigerate at 2–8 °C (35.6–46.4 °F); use within 28 days. Avoid freeze–thaw; aliquot if needed

Used for

No condition evidence rows yet.

Legal / compounding

Research use only
EU
Not Approved
FDA
Not Approved
Canada
Not Approved
Australia
Not Approved

Legal status is a hard gate: non-compoundable or delisted agents cannot be filled and are blocked from protocol export. Keep 503A status current.