Overview
GHRP-2 is a growth hormone-related peptide. Growth hormone releasing hexapeptide.
With a half-life of ~15 minutes, GHRP-2 requires daily administration in most observed protocols. Administered via SubQ injection, it has a bioavailability of approximately 95% via its primary route.
Half-life approximately 15 minutes. Very rapid plasma clearance. Less selective GH release profile than ipamorelin. Subcutaneous administration. One-compartment model.
Mechanism of Action
GHRP-2's pharmacological activity involves the following key pathways:
Ghrelin Receptor Agonism
GHRP-2 acts as a growth hormone secretagogue by binding to the ghrelin (GHS-R1a) receptor, triggering GH release from the pituitary.
Synergy with GHRH
GH secretagogues like GHRP-2 work synergistically with GHRH analogs — co-administration amplifies GH release beyond what either produces alone.
Dosing Protocols
The following protocols represent commonly observed dosing patterns. These are observational summaries, not recommendations.
Dose
100 mcg/day
Route
Subcutaneous
Frequency
2-3 times daily
Duration
4-12 weeks
Dose
300 mcg/day
Route
Subcutaneous
Frequency
2-3 times daily
Duration
4-12 weeks
Reconstitution Steps
GHRP-2 is supplied as a lyophilized (freeze-dried) powder and requires reconstitution before use. Common vial sizes: 2 mg, 5 mg, 10 mg.
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1
Gather supplies
You will need the GHRP-2 vial, bacteriostatic water (BW), a sterile syringe for reconstitution, insulin syringes for dosing, and alcohol swabs.
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2
Clean both vial tops
Wipe the rubber stopper of both the GHRP-2 vial and the bacteriostatic water vial with separate alcohol swabs. Allow to air dry for 10 seconds.
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3
Draw bacteriostatic water
For a 5 mg vial, draw 2.0 mL of bacteriostatic water. This yields a concentration of 2,500 mcg/mL, so each 0.1 mL (10 units on an insulin syringe) contains 250 mcg.
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4
Inject slowly down the vial wall
Angle the needle so the water runs down the inside wall of the GHRP-2 vial rather than directly onto the powder. This prevents foaming and protects the peptide structure.
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5
Gently swirl to dissolve
Gently roll the vial between your palms until the powder is fully dissolved. Do not shake — GHRP-2 is a fragile peptide and agitation can degrade it.
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6
Store correctly
Refrigerate the reconstituted vial at 2–8°C. GHRP-2 is stable for up to 28 days post-reconstitution when kept refrigerated and protected from light. Do not freeze the reconstituted solution.
Quick Reconstitution Math
5 mg vial + 2.0 mL BW = 2,500 mcg/mL. A 100 mcg dose = 0.04 mL (4 units on an insulin syringe). A 200 mcg dose = 0.08 mL (8 units). Use the Milligram reconstitution calculator for custom vial sizes.
Store lyophilized powder at 2–8°C (refrigerator). After reconstitution with bacteriostatic water, refrigerate at 2–8°C and use within 28 days. Do not freeze reconstituted solution.
Frequently Asked Questions
What is GHRP-2 and how does it work?
GHRP-2 (pralmorelin) is a synthetic hexapeptide that binds to the ghrelin receptor (GHS-R1a) on pituitary somatotroph cells and in the hypothalamus, triggering a rapid, potent pulse of growth hormone release. It is considered a second-generation GHRP and produces among the highest peak GH release of any peptide in its class. Unlike GHRH-based peptides, GHRP-2 works through a complementary pathway – making it a synergistic partner when stacked with CJC-1295 or sermorelin.
What is the half-life of GHRP-2 and how often should it be dosed?
GHRP-2 has a plasma half-life of approximately 15–30 minutes, with peak GH concentrations typically observed within 15–25 minutes of injection. Because GH levels return to baseline within 60–90 minutes, two to three injections per day are commonly used to create multiple GH pulses. Each injection is typically administered on an empty stomach for maximal GH output.
Does GHRP-2 increase cortisol and prolactin?
Clinical research has observed that GHRP-2 produces dose-dependent increases in prolactin, ACTH, and cortisol alongside GH release – an effect shared with GHRP-6 but not seen with the more selective ipamorelin. These hormonal co-activations are most pronounced at doses above 300–600 mcg and represent the primary trade-off compared to cleaner GHRP compounds. The cortisol increase is transient and corresponds to the GH pulse window.
How does GHRP-2 compare to GHRP-6 and ipamorelin?
GHRP-2 produces higher peak GH release than ipamorelin and comparable or slightly higher output than GHRP-6, while its appetite-stimulating effects are notably milder than GHRP-6. The trade-off for greater GH output is the moderate cortisol and prolactin co-elevation that both GHRP-2 and GHRP-6 share. Ipamorelin is the most selective option with minimal hormonal side effects, while GHRP-2 sits in the middle – stronger GH output with manageable appetite stimulation.
What are the common effects of GHRP-2?
Commonly reported effects include increased hunger within 15–30 minutes of injection (milder than GHRP-6), mild water retention in the first few weeks, improved sleep quality, and enhanced recovery. IGF-1 elevation is observed with consistent multi-dose daily protocols. Tingling or numbness in the extremities is occasionally reported, consistent with elevated GH levels.
Can GHRP-2 be stacked with other peptides?
GHRP-2 is frequently stacked with GHRH-class peptides such as CJC-1295 (no DAC) or sermorelin, as the two pathways are complementary – combined administration produces GH peaks 2–3 times higher than either agent alone. MK-677 is sometimes combined to provide sustained baseline GH elevation between pulse doses. Stacking GHRP-2 with other GHRPs such as GHRP-6 or hexarelin is not commonly observed, as they compete for the same GHS-R1a receptor.