GHRP-2
Also known as: Growth Hormone Releasing Peptide 2, Pralmorelin, KP-102, GHRP2
GHRP-2 (Pralmorelin) is a synthetic hexapeptide growth hormone secretagogue that acts on the ghrelin/GHS receptor to stimulate pituitary growth hormone release. It is one of the most potent GHRPs studied, with a strong and consistent GH-releasing effect.
GHRP-2 is a 817.97 Da research peptide. GHRP-2 (Pralmorelin) is a synthetic hexapeptide growth hormone secretagogue that acts on the ghrelin/GHS receptor to stimulate pituitary growth hormone release. It is one of the most potent GHRPs studied, with a strong and consistent GH-releasing effect.
Also called: Growth Hormone Releasing Peptide 2, Pralmorelin, KP-102
817.97
Molecular Weight
Daltons
3
Strong Evidence
benefits
5
Studies Cited
peer-reviewed
100-300
Typical Dose
mcg
Overview
GHRP-2 (Growth Hormone Releasing Peptide 2), also known as Pralmorelin or KP-102, is a synthetic hexapeptide that belongs to the growth hormone secretagogue (GHS) class. It acts primarily by binding to the growth hormone secretagogue receptor (GHS-R1a), the same receptor targeted by the endogenous hormone ghrelin. GHRP-2 stimulates the anterior pituitary gland to release growth hormone in a pulsatile manner that mimics natural GH secretion patterns. Among the GHRP family, GHRP-2 is considered one of the most potent stimulators of GH release, producing strong and reliable GH pulses. It has been used clinically in Japan as a diagnostic tool for growth hormone deficiency (marketed under the name Pralmorelin/GHRP Kaken) and has been extensively studied for its effects on GH axis physiology, body composition, appetite regulation, and sleep architecture. GHRP-2 also stimulates modest increases in prolactin, cortisol, and ACTH at higher doses, though these effects are less pronounced than with GHRP-6.
Key Takeaways: GHRP-2
- Strongest evidence supports GHRP-2 for potent growth hormone release and gh deficiency diagnosis
- Research doses typically range from 100 to 300 mcg via subcutaneous injection
- 3 benefits with strong evidence, 2 moderate, 1 preliminary
- Half-life: Approximately 25-30 minutes
- 5 cited research studies in this guide
Mechanism of Action
GHRP-2 exerts its primary effect by binding to the GHS-R1a (ghrelin receptor) on somatotroph cells in the anterior pituitary gland. This receptor activation triggers intracellular calcium signaling cascades that stimulate the release of stored growth hormone granules. GHRP-2 also acts at the hypothalamic level, stimulating GHRH (growth hormone releasing hormone) neurons and suppressing somatostatin release, creating a dual amplification of GH secretion. The peptide works cooperatively with endogenous GHRH and with exogenous GHRH analogs like CJC-1295, producing GH pulses significantly larger than either agent alone. At the cellular level, GHRP-2 activates the phospholipase C/IP3/PKC pathway and increases intracellular calcium through both IP3-sensitive calcium stores and voltage-gated calcium channels. GHRP-2 also has direct effects on appetite regulation through hypothalamic ghrelin receptor activation, though its orexigenic (appetite-stimulating) effect is less pronounced than GHRP-6. Higher doses can stimulate modest cortisol and prolactin release through non-GH pathways, but this effect shows tachyphylaxis (diminishing response) with repeated use.
Research Benefits
GHRP-2 at a Glance
GHRP-2 exerts its primary effect by binding to the GHS-R1a (ghrelin receptor) on somatotroph cells in the anterior pituitary gland.
Potent Growth Hormone Release
Strong EvidenceGHRP-2 produces strong, reliable GH pulses from the pituitary. Clinical studies show it is among the most potent GHRPs, with significant GH elevation even in elderly subjects with diminished natural GH output.
GH Deficiency Diagnosis
Strong EvidenceApproved in Japan as a diagnostic agent (Pralmorelin) for growth hormone deficiency. The standardized GHRP-2 stimulation test is used clinically to assess pituitary GH reserve.
Synergy with GHRH Analogs
Strong EvidenceProduces amplified GH release when combined with GHRH or GHRH analogs (e.g., CJC-1295). Combined administration yields GH pulses far exceeding either peptide alone.
Improved Sleep Quality
Moderate EvidenceResearch shows GHRP-2 increases slow-wave (deep) sleep duration and enhances natural nocturnal GH pulses, aligning with the physiological pattern of GH secretion during sleep.
Body Composition
Moderate EvidenceThrough sustained GH elevation, studies demonstrate improvements in lean body mass, reduction in visceral adiposity, and enhanced recovery in research models.
Cytoprotective Effects
PreliminaryEmerging research suggests GHRP-2 may have cardioprotective and hepatoprotective properties independent of GH release, potentially through direct ghrelin receptor activation in peripheral tissues.
Research Dosing Protocols
Research Purposes Only: All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.
| Research Protocol | Dose Range | Route |
|---|---|---|
| Standard GH stimulation protocol | 100–300 mcg | Subcutaneous injection |
| Clinical diagnostic test dose | 1–1 mcg/kg | Intravenous (clinical setting only) |
| Saturation dose (diminishing returns above this) | 100–200 mcg | Subcutaneous injection |
Frequency
1-3 times daily
Timing
Fasted state preferred (at least 30 min before or 2 hours after food). Pre-bed dosing supports nocturnal GH pulse.
Cycle Length
8-16 weeks typical; can be used long-term with periodic breaks
Research Notes
- 1GH response is blunted by food intake, especially fats and carbohydrates; dose on an empty stomach.
- 2The saturation dose is approximately 100-200 mcg; higher doses do not proportionally increase GH but do increase cortisol and prolactin.
- 3Often combined with a GHRH analog (CJC-1295 or Mod GRF 1-29) for enhanced GH release.
- 4GHRP-2 produces less appetite stimulation than GHRP-6 but more than Ipamorelin.
- 5Cortisol and prolactin elevations at standard doses are generally mild and transient.
Reconstitution Guide
Standard Reconstitution
Vial Size
5 mg
Bacteriostatic Water
2 mL
Concentration
25 mcg
per 0.1 mL (10 units)
Step-by-Step Guide
Gather Materials
GHRP-2 vial, bacteriostatic water, alcohol swabs, insulin syringes.
Equilibrate Temperature
Remove the vial from storage and allow it to reach room temperature (5-10 minutes).
Sanitize
Swab the rubber stopper of both the peptide vial and bacteriostatic water vial with alcohol.
Draw Water
Draw 2 mL of bacteriostatic water into a syringe.
Add Water to Vial
Insert the needle into the peptide vial and direct the water stream against the glass wall — not directly onto the powder.
Mix Gently
Swirl the vial gently until the powder is fully dissolved. Never shake. The solution should be clear and colorless.
Store Properly
Refrigerate at Refrigerated (2-8°C / 36-46°F) after reconstitution. Up to 30 days refrigerated after reconstitution.
Storage Temperature
Refrigerated (2-8°C / 36-46°F) after reconstitution
Shelf Life
Up to 30 days refrigerated after reconstitution
Important Notes
- •Use bacteriostatic water for reconstitution.
- •Store lyophilized powder frozen (-20°C) for long-term storage.
- •Swirl gently; do not shake.
- •Solution should be clear and colorless.
- •Standard reconstitution: 5 mg vial + 2 mL BAC water = 2,500 mcg/mL.
GHRP-2 Dosing Calculator
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GHRP-2 Reconstitution Calculator
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Safety & Side Effects
Reported Side Effects
- !Increased appetite (less than GHRP-6 but more than Ipamorelin)
- !Transient cortisol elevation at higher doses
- !Mild prolactin increase (dose-dependent, transient)
- !Water retention (mild, due to GH effects)
- !Tingling or numbness in extremities (paresthesia, from GH elevation)
- !Headache (infrequent)
- !Flushing at injection site
- !Potential for elevated blood glucose with sustained high-dose use
Potential Interactions
- ⚡complementary with GHRH analogs (CJC-1295, Mod GRF 1-29, Sermorelin), dramatically amplifies GH release.
- ⚡GH release is blunted by somatostatin and somatostatin analogs (octreotide, lanreotide).
- ⚡Potential interaction with insulin — GH can antagonize insulin sensitivity.
- ⚡May interact with glucocorticoids which can suppress GH release.
- ⚡Caution with dopamine agonists (cabergoline) due to prolactin pathway overlap.
Important: Side effects and interactions listed here are compiled from published research and community reports. This is not a complete list. No formal drug interaction studies have been conducted for most research peptides. Always consult a qualified healthcare provider.
Research Studies
The following studies are referenced in this profile. PubMed IDs are provided where available for independent verification.
Growth hormone releasing peptide-2 (GHRP-2): GH, ACTH, cortisol and prolactin release in humans
Foundational study characterizing GHRP-2's hormonal effects in humans, establishing its potent GH-releasing activity and documenting dose-dependent cortisol and prolactin responses.
Diagnosis of adult GH deficiency with GHRP-2 stimulation test
Validated the GHRP-2 stimulation test as a reliable diagnostic tool for adult GH deficiency, establishing clinical cutoff values and demonstrating high sensitivity and specificity.
complementary release of growth hormone by GHRP-2 and GHRH in humans
Demonstrated that combined GHRP-2 + GHRH administration produces GH release far exceeding either agent alone, establishing the rationale for combination protocols.
GHRP-2 increases slow-wave sleep and GH secretion in healthy subjects
Showed GHRP-2 administration enhances slow-wave sleep duration and amplifies the natural nocturnal GH pulse, supporting its use for sleep-timed GH optimization.
Cardioprotective effects of growth hormone-releasing peptide-2 in rats
Demonstrated direct cardioprotective effects of GHRP-2 in ischemia-reperfusion models, suggesting GH-independent protective mechanisms through peripheral ghrelin receptor activation.
Note: This is not an exhaustive list of all published research. Studies are selected for relevance and quality. Click PubMed IDs to verify sources independently. Inclusion does not imply endorsement of the peptide for any clinical use.
Frequently Asked Questions
GHRP-2 (Pralmorelin) is a synthetic growth hormone releasing peptide that stimulates the pituitary gland to release growth hormone. It acts on the ghrelin receptor and is one of the most potent GHRPs available, approved in Japan for GH deficiency diagnosis.
Both stimulate GH release through the ghrelin receptor, but GHRP-2 is considered more potent with a cleaner GH release profile. GHRP-6 causes significantly more appetite stimulation (hunger) and slightly more cortisol/prolactin elevation. GHRP-2 is generally preferred when appetite stimulation is undesirable.
Yes. GH release from GHRP-2 is significantly blunted by food intake, particularly fats and carbohydrates. Dose at least 30 minutes before eating or 2 hours after a meal for optimal GH response.
Yes. GHRP-2 and GHRH analogs like CJC-1295 (with or without DAC) work through complementary pathways. GHRP-2 acts on the ghrelin receptor while CJC-1295 acts on the GHRH receptor, producing a much larger GH pulse than either alone. This is one of the most common research combinations.
GHRP-2 can cause a mild, transient cortisol elevation, particularly at higher doses. At the standard saturation dose (100-200 mcg), cortisol elevation is generally modest and short-lived. This effect tends to diminish with repeated use.
The saturation dose is approximately 100-200 mcg (or roughly 1 mcg/kg body weight). Above this dose, GH release does not increase proportionally, but side effects like cortisol and prolactin elevation do increase. Multiple daily doses at the saturation level are more effective than single larger doses.
Research & Educational Use Only
All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.
The information presented here is compiled from published research studies and is intended for informational purposes only. Individual results may vary. Always consult with a licensed healthcare provider.