GHRP-2 (pralmorelin, KP-102) is one of the most clinically studied growth hormone releasing peptides. Originally developed as a diagnostic tool for GH deficiency, it has become a reference compound for understanding how synthetic ghrelin mimetics drive pulsatile GH release. GHRP-2 is not FDA-approved for therapeutic use. This is not medical advice.
Research-context information only. GHRP-2 is a research peptide. Protocols, doses, and reactions reported below come from published research and self-reported community sources. This article reports what has been documented, not what should be done. Consult a licensed physician for personal medical decisions.
Note: GHRP-2 has no standardized clinical dosing protocol for this use. The protocol below is a Community Protocol based on clinical research data and community experience.
Parameter Community Protocol (self-reported, not a prescribing guide — see note below) Dose 100-300 mcg per injection (community-reported) Route Subcutaneous injection (abdomen or thigh) Timing Empty stomach (30-60 min before meals) (community-reported) Frequency 2-3 times daily, 3+ hours apart; 5 days on / 2 days off (community-reported) Cycle 8 weeks on, 8 weeks off (community-reported) Vial size 10 mg Reconstitution 5 mL bacteriostatic water → 2 mg/mL Draw amount (community-reported) 5 units (100 mcg) / 10 units (200 mcg) / 15 units (300 mcg) — see mg-to-units section Storage Refrigerate, use within 28 days
Most common approach: 100-200 mcg per injection (the clinical research range), 2-3 times daily on empty stomach. Common timing: morning fasted, pre-workout, and before bed.
For the full GHRP-2 peptide profile, vendor pricing, and stack protocols, see our GHRP-2 peptide page. For a research-backed breakdown of what GHRP-2 actually does beyond GH release, see our GHRP-2 Benefits Guide.
Cycling Details
GHRP-2 doesn't use loading phases. Documented community protocols describe consistent 100-300 mcg doses, 2-3 times daily, 5 days on / 2 days off. A five-day treatment study showed response attenuation with consecutive daily use (Raun et al., 1998), making the 5-on/2-off pattern important.
8 weeks on, 8 weeks off is the common community pattern for long-term cycling, generally for cost and to let IGF-1 and the HPA axis normalize. The short half-life (~15-30 minutes) means each injection provides an acute GH pulse rather than sustained elevation. For how the ghrelin and GHRH peptide families differ on desensitization, see Do GH Peptides Desensitize the Pituitary?.
Empty stomach timing: Documented protocols describe injecting 30-60 minutes before eating or 2+ hours after meals. Elevated blood glucose and free fatty acids significantly blunt the GH response.
Community-reported timing clusters around morning fasted + before bed (2x/day), or morning fasted + pre-workout + before bed (3x/day).
Routes of Administration
Subcutaneous injection (standard): Belly fat, thigh, or anywhere with SC tissue. Volume: 0.1-0.2 mL with insulin syringe (29-31 gauge). Trial protocols describe rotating injection sites.
Reconstitution Quick Reference
Vial Size BAC Water Concentration 100 mcg 200 mcg 300 mcg 10 mg 5 mL 2 mg/mL 5 units 10 units 15 units
Math: 10,000 mcg / 5 mL = 2,000 mcg/mL. For 200 mcg: 200 / 2,000 = 0.1 mL = 10 units. One vial lasts 50 doses at 200 mcg.
Community reconstitution protocols describe gentle swirling, not shaking, then refrigeration at 2-8°C and use within 28 days. For step-by-step instructions, see the Reconstitution Calculator.
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Where These Numbers Come From
Unlike many research peptides, GHRP-2 community doses closely align with published clinical research.
Diagnostic testing: 100 mcg (1 mcg/kg) is the standard dose for GH deficiency diagnosis, producing robust GH pulses in healthy individuals (PMID: 17609397).
Research studies: 200 mcg (2-3 mcg/kg) used in studies examining GH secretory dynamics (PMID: 18703567).
Plateau effect: Higher doses (300+ mcg) don't increase GH proportionally but do increase cortisol and prolactin side effects.
GH response data (trial-reported): Published studies report peak GH levels of 30-80 ng/mL at 100-200 mcg doses. Time to peak: 30-60 minutes, duration approximately 2-3 hours elevated (PMID 17609397; PMID 18703567). GHRH co-administration produces 3-10x greater response than either alone (Veldhuis et al., 2009).
Why doses align with research: GHRP-2 is approved in Japan as pralmorelin for GH testing. This established effective dose ranges directly, unlike most peptides that require extrapolation from animal studies.
Stacking Protocols
Stack Components Purpose Most Evidence-Supported GHRP-2 100-200 mcg + CJC-1295 200 mcg (simultaneous, PM) GHSR-1a + GHRHR synergy = 3-10x GH release + Sermorelin GHRP-2 100-200 mcg + Sermorelin Shorter-acting GHRH alternative
GHRP-2 + GHRH synergy leverages two different receptor pathways: GHRP-2 via GHSR-1a (calcium/PKC) and CJC-1295 via GHRHR (cAMP/PKA) (Veldhuis et al., 2009).
For comprehensive stacking strategies, see our Peptide Stacking Guide.
Side Effects & Safety
Cortisol elevation -- transient ACTH/cortisol increase via HPA axis; dose-dependent, mild at 100-200 mcg Prolactin elevation -- less than hexarelin, more than ipamorelin; returns to baseline within 2-3 hours Appetite stimulation -- ghrelin mimetic effect, peaks 20-30 min post-injection; milder than GHRP-6 Water retention -- mild, GH-mediated sodium retention Response attenuation -- a five-day study reported declining GH response with consecutive daily use (Raun et al., 1998); community sources use 5-on/2-off to manage this Injection site reactions -- standard for SC peptides
GHRP family comparison:
GHRP GH Release Cortisol/Prolactin Appetite Ipamorelin Moderate Minimal Minimal GHRP-2 Strong Moderate Mild GHRP-6 Strong Moderate Strong Hexarelin Strongest Highest Moderate
mg to Units Conversion
On a standard 100-unit insulin syringe, each "unit" equals 0.01 mL (so 100 units = 1 mL). Once GHRP-2 is reconstituted, the conversion from a target dose to syringe units depends on the chosen dilution.
The two reconstitution ratios most often described in community protocols are below.
Reconstitution A: 10 mg vial + 5 mL BAC water (2 mg/mL) — the standard dilution from the Quick Reference above.
Dose (mcg) Volume (mL) Units (insulin syringe) 100 mcg 0.05 mL 5 units 200 mcg 0.1 mL 10 units 300 mcg 0.15 mL 15 units 400 mcg 0.2 mL 20 units
Reconstitution B: 10 mg vial + 10 mL BAC water (1 mg/mL) — more BAC water for larger, easier-to-measure draws.
Dose (mcg) Volume (mL) Units (insulin syringe) 100 mcg 0.1 mL 10 units 200 mcg 0.2 mL 20 units 300 mcg 0.3 mL 30 units 400 mcg 0.4 mL 40 units
These conversions reflect the dilutions documented in community reconstitution protocols. They report how the math is described, not a recommended dosing schedule.
Core Supplies for This Protocol
The three essentials for running any reconstituted injectable: cold storage, accurate syringes, and metabolic tracking.
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GHRP-2 Benefits Guide -- Research-backed effects beyond GH release GHRP-2 Peptide Page -- Full profile, vendor pricing, and comparisons GHRH vs GHRP -- Mechanistic breakdown of the two peptide classes Ipamorelin vs GHRP-2 vs GHRP-6 -- Three-way GHRP comparison CJC-1295 No DAC Dosing Guide -- GHRH analog for stacking Hexarelin Dosing Guide -- Strongest GHRP comparison Peptide Stacking Guide -- How to combine peptides Calculate Your GHRP-2 Cycle Cost -- estimate vials needed and total cost Best Peptides for Muscle Growth (2026) -- all 10 muscle-building peptides ranked GHRP-2 Buying Guide — GH-secretagogue sourcing + COA standards
References
Citation Topic PMID Bowers CY, Cell Mol Life Sci (1998) GHRP overview 9893708 Howard et al., Science (1996) GHSR-1a receptor discovery 8688086 Kojima et al., Nature (1999) Ghrelin identification 10604470 Simple diagnostic test using GHRP-2, Endocr J (2007) Clinical diagnostic applications 17609397 Secretagogues govern GH waveform, Am J Physiol (2008) GH response dynamics 18703567 Raun et al., Growth Horm IGF Res (1998) Desensitization with consecutive use 9820615 Veldhuis et al., J Clin Endocrinol Metab (2009) GHRP + GHRH synergy 19240251
For educational and research purposes only. This is not medical advice. GHRP-2 is a research compound not approved for therapeutic use.