GHRP-2 Dosing Guide: Protocols & GH Response (2026)

GHRP-2 (pralmorelin, KP-102) is one of the most studied growth hormone releasing peptides in the clinical literature. 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 from the anterior pituitary.

GHRP-2 is not FDA-approved for therapeutic use. Everything below reflects published research and community protocols. This is not medical advice.

Quick Reference: Community Dosing

If you're here for the practical protocol, here it is:

Most people use: 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.

Loading vs Maintenance

GHRP-2 protocols don't typically use loading phases, but do consider cycling patterns:

Standard Approach: Consistent 100-300 mcg doses throughout the protocol. GHRP-2's short half-life (~15-30 minutes) means each injection provides an acute GH pulse rather than sustained elevation.

Cycling: 5 days on, 2 days off to prevent GHSR-1a desensitization. A five-day treatment study showed response attenuation with consecutive daily use (Raun et al., 1998).

Protocol Length: 8 weeks on, 8 weeks off is common for long-term use.

Routes of Administration

Subcutaneous Injection (Most Common)

The standard route for community protocols. Inject into belly fat, thigh, or anywhere with subcutaneous tissue.

• Volume: Typically 0.1–0.2 mL with insulin syringe (29–31 gauge)
• Absorption: Provides rapid systemic distribution for GH pulse
• Sites: Rotate injection sites to prevent lipodystrophy

Timing Considerations

Empty stomach essential: GHRP-2 should be administered 30-60 minutes before eating or 2+ hours after meals. Elevated blood glucose and free fatty acids significantly blunt the GH response.

Frequency: 2-3 times daily with at least 3 hours between doses allows GHSR-1a resensitization.

Common timing patterns:

• Morning fasted + before bed
• Morning fasted + pre-workout + before bed
• Spacing around meal windows

Where These Numbers Come From: Clinical Context

Unlike many research peptides, GHRP-2 community doses closely align with published clinical research — this is one of the few peptides where the research directly supports community protocols.

Clinical Research Doses

The vast majority of clinical research uses 1-2 mcg/kg, which translates to 100-200 mcg for most adults:

Diagnostic testing: 100 mcg (1 mcg/kg) is the standard dose for GH deficiency diagnosis, producing robust GH pulses in healthy individuals (Simple diagnostic test using GHRP-2, 2007).

Research studies: 200 mcg (2-3 mcg/kg) used in studies examining GH secretory dynamics (Secretagogues govern GH secretory-burst waveform, 2008).

Upper range: 300 mcg represents the high end where dose-response plateaus due to receptor saturation.

Why Community and Clinical Doses Align

This is unusual in the peptide world — most peptides require significant extrapolation from animal studies. With GHRP-2:

• Direct human data: Extensive clinical research in humans, not just animals
• Diagnostic use: Approved in Japan as pralmorelin for GH testing, establishing effective dose ranges
• Well-characterized pharmacology: Dose-response relationship clearly defined in clinical studies
• Plateau effect: Higher doses don't increase GH proportionally but do increase side effects (cortisol, prolactin)

GH Response Data

Clinical studies show predictable GH responses:

• Peak GH levels: 30-80 ng/mL at 100-200 mcg doses
• Time to peak: 30-60 minutes post-injection
• Duration: 2-3 hours elevated before return to baseline
• Synergy with GHRH: 3-10× greater response when combined with CJC-1295 or sermorelin

Mechanism of Action

GHRP-2 is a synthetic ghrelin mimetic that binds the GHSR-1a receptor, triggering pulsatile GH release from the anterior pituitary through a calcium/PKC signaling pathway distinct from GHRH's cAMP/PKA pathway — which is why the two classes synergize so powerfully. For the full mechanistic breakdown of GHRPs vs GHRHs, see our GHRH vs GHRP guide.

Side Effects & Safety

GHRP-2 occupies the middle ground in the GHRP family for side effects — more than ipamorelin but less than hexarelin:

Common Side Effects

Cortisol elevation — GHRP-2 stimulates the HPA axis through CRF release, causing transient ACTH and cortisol increases. The effect is dose-dependent and typically mild to moderate at 100-200 mcg doses.

Prolactin elevation — Less pronounced than hexarelin but more than ipamorelin. Generally returns to baseline within 2-3 hours.

Appetite stimulation — As a ghrelin mimetic, GHRP-2 increases hunger 20-30 minutes post-injection. Generally milder than GHRP-6 but more than ipamorelin.

Water retention — Some users report mild fluid retention, likely related to GH-mediated sodium retention.

GHRP Family Comparison

Desensitization

Five-day consecutive use leads to response attenuation, making cycling protocols (5 on / 2 off) important for maintaining efficacy.

Stacking GHRP-2

GHRP-2's strongest evidence base involves combination with GHRH analogs for synergistic GH release.

GHRP-2 + CJC-1295 (Most Evidence-Supported Stack)

This combination leverages two different receptor pathways:

• GHRP-2: GHSR-1a → Gq → PLC → PKC → calcium release
• CJC-1295: GHRHR → Gs → cAMP → PKA → calcium channel modulation

Result: Synergistic GH release 3-10× greater than either peptide alone (Veldhuis et al., 2009).

Other Stacking Options

GHRP-2 + Sermorelin: Shorter-acting GHRH analog with similar synergy mechanism but requiring more frequent dosing.

GHRP-2 + Ipamorelin: Some users combine GHRPs, but evidence is limited compared to GHRP + GHRH combinations.

For comprehensive stacking strategies, see our Peptide Stacking Guide.

Frequently Asked Questions

What is the standard GHRP-2 dose?

The most common community protocol is 100-300 mcg per injection, 2-3 times daily on empty stomach. This matches clinical research doses of 1-2 mcg/kg (100-200mcg for most adults).

Should I take GHRP-2 on an empty stomach?

Yes — GHRP-2 should be taken 30-60 minutes before eating or 2+ hours after meals. Elevated blood glucose and free fatty acids blunt the GH response to GHRP-2.

Does GHRP-2 cause hunger like GHRP-6?

GHRP-2 causes mild appetite stimulation as a ghrelin mimetic, but generally less than GHRP-6. The effect peaks 20-30 minutes after injection and is dose-dependent.

Can GHRP-2 be stacked with CJC-1295?

Yes — this is the most evidence-supported stack. GHRP-2 (GHSR-1a pathway) and CJC-1295 (GHRHR pathway) produce synergistic GH release 3-10× greater than either alone.

How often should I inject GHRP-2?

2-3 times daily with 3+ hours between doses. GHRP-2 has a short half-life (~15-30 minutes), so frequent dosing maintains tissue exposure. Most protocols use 5 days on / 2 days off to prevent desensitization.

Does GHRP-2 increase cortisol?

Yes — GHRP-2 stimulates ACTH and cortisol release through hypothalamic CRF pathways. The effect is dose-dependent and typically mild to moderate at standard doses (100-200mcg).

What's the difference between GHRP-2 and ipamorelin?

GHRP-2 produces stronger GH release but with more cortisol/prolactin elevation. Ipamorelin is more selective with minimal side effects but less potent. For a detailed comparison, see our GHRP comparison guide.

Does GHRP-2 suppress natural GH production?

No — unlike exogenous GH, GHRP-2 stimulates endogenous production through the pituitary's own machinery. However, chronic use may lead to GHSR-1a desensitization, making cycling protocols important.

Related Guides

• GHRP-2 Peptide Page — Vendor pricing, stack protocols, and full peptide profile
• GHRH vs GHRP — Mechanistic breakdown of the two peptide classes
• CJC-1295 vs Sermorelin — Comparing GHRH analogs for stacking
• Ipamorelin vs GHRP-2 vs GHRP-6 — Three-way GHRP comparison
• Hexarelin: Strongest GHRP — The most potent growth hormone peptide
• Peptide Stacking Guide — How to combine peptides effectively

References

This article is for educational and informational purposes only. It is not medical advice. GHRP-2 is a research compound — consult a qualified healthcare provider before considering any peptide protocol.