GHRP-2 Dosage Guide

GHRP-2 dosing — expressed in micrograms (mcg) per injection — is based on a combination of clinical pharmacology studies, dose-response research in healthy volunteers, and extensive community experience. Unlike most research peptides, GHRP-2 has been studied in humans (primarily for diagnostic purposes in Japan), providing a stronger evidence base than many other GH secretagogues.

Clinical Studies

Human studies using intravenous GHRP-2 at doses of 1 mcg/kg body weight demonstrated significant, reproducible GH release — this is the basis for its use as a diagnostic agent in Japan. Subcutaneous administration at 100–300 mcg has been studied in various clinical settings, showing dose-dependent GH release that plateaus around 200–300 mcg per injection (approximately 2–3 mcg/kg for a 75–100 kg individual).

Dose-Response & Receptor Saturation

Research by Bowers and colleagues established that GHRP-2's GH-releasing effect follows a saturable dose-response curve. Increasing the dose beyond approximately 200–300 mcg per injection does not proportionally increase GH output — the GHS-R1a receptors become saturated. However, higher doses do increase cortisol, prolactin, and appetite stimulation. This is why the community consensus settles on 100–300 mcg as the effective range, with 200 mcg being the most common dose.

Fasting Requirement

Multiple studies have confirmed that elevated blood glucose and insulin levels dramatically suppress GHRP-2's GH-releasing effect. Laferrere et al. demonstrated that the GH response to GHRP-2 is reduced by 50–80% in a fed state compared to a fasted state. This makes fasting the single most important protocol variable — more important than the exact dose chosen.

GHRP-2 is supplied as a lyophilized (freeze-dried) powder, typically in 5 mg or 10 mg vials. You reconstitute it with bacteriostatic water, then draw your dose using an insulin syringe. The concentration depends on how much water you add to the vial.

Quick Reference — 5 mg Vial

GHRP-2's core mechanism — stimulating pulsatile GH release from the pituitary — supports a range of goals. The optimal dosing protocol varies by what you are trying to achieve.

GH Optimization & Anti-Aging

The most common use case for GHRP-2 — restoring youthful GH levels that decline with age. Elevated GH and IGF-1 support skin quality, connective tissue health, body composition, sleep quality, and overall vitality. Lower doses are sufficient for this goal.

• Dose: 100–200 mcg per injection (SubQ)
• Frequency: 2x daily (morning fasted + bedtime)
• Stack with: CJC-1295 (no DAC) at 100–200 mcg for amplified effect
• Duration: 8–16 weeks on, 4–8 weeks off

Muscle Growth & Recovery

Higher GH and IGF-1 levels support muscle protein synthesis, nitrogen retention, and faster recovery from resistance training. GHRP-2 is not anabolic on its own like exogenous GH or testosterone — the muscle-building effect is indirect, through elevated endogenous GH.

• Dose: 200–300 mcg per injection (SubQ)
• Frequency: 2–3x daily (morning, optional post-workout window, bedtime)
• Stack with: CJC-1295 at 200 mcg per injection for maximum GH output
• Duration: 12–16 weeks on, 4–8 weeks off

Fat Loss

GH is a potent lipolytic hormone — it mobilizes fatty acids from adipose tissue for oxidation. GHRP-2's ability to elevate GH supports fat loss, particularly when combined with caloric restriction and exercise. The fasted morning dose is especially effective for this purpose.

• Dose: 200 mcg per injection (SubQ)
• Frequency: 2–3x daily (fasted)
• Stack with: CJC-1295 for enhanced GH pulse; consider AOD-9604 as an add-on for direct lipolysis
• Duration: 8–16 weeks on, 4–8 weeks off

Injury Recovery & Tissue Repair

Elevated GH and IGF-1 support collagen synthesis, tendon repair, and connective tissue healing. While GHRP-2 is not a localized tissue repair peptide like BPC-157, the systemic GH elevation supports recovery from injuries and surgical procedures.

• Dose: 200 mcg per injection (SubQ)
• Frequency: 2–3x daily (fasted)
• Stack with: BPC-157 (250 mcg near injury) + TB-500 for comprehensive recovery
• Duration: 8–12 weeks or as guided by recovery progress

Sleep Quality

The bedtime GHRP-2 dose amplifies the natural nocturnal GH surge, which is the largest GH pulse of the day. Users frequently report improved sleep depth and quality as one of the first noticeable effects, often within the first week of use.

• Dose: 100–200 mcg (SubQ)
• Frequency: Once daily at bedtime (minimum effective protocol)
• Timing: 30–60 minutes before sleep, at least 2 hours after last meal
• Duration: 8–16 weeks on, 4–8 weeks off

GHRP-2 is typically run in cycles of 8–16 weeks followed by an off period. Unlike exogenous GH, GHRP-2 does not suppress natural GH production — it stimulates your own pituitary to release GH. No post-cycle therapy (PCT) is needed. However, cycling is still recommended to prevent potential receptor desensitization with extended use.

No PCT Required

GHRP-2 stimulates your own pituitary to release GH — it does not introduce exogenous hormones or suppress the hypothalamic-pituitary axis the way exogenous GH or anabolic steroids do. When you stop GHRP-2, your natural GH production simply returns to its baseline level. No taper or post-cycle therapy is needed.

Monitoring

• IGF-1 blood test: The best proxy for average GH levels. Test at baseline (before starting), at 4–6 weeks, and at the end of the cycle. Target a healthy, age-appropriate IGF-1 level — not supraphysiological.
• Fasting glucose: GH is a counter-regulatory hormone to insulin. Sustained GH elevation can reduce insulin sensitivity. Monitor fasting glucose, especially if you have pre-diabetes risk factors.
• Prolactin (optional): If using doses above 200 mcg, periodic prolactin testing is reasonable, especially if symptoms appear (nipple sensitivity, libido changes).

Common Side Effects

Dose-dependent and generally transient:

• Increased appetite — moderate; peaks 15–30 minutes after injection and subsides within 30–60 minutes
• Cortisol elevation — transient at standard doses (100–200 mcg); more pronounced above 300 mcg; returns to baseline within 1–2 hours
• Prolactin elevation — mild to moderate at standard doses; more significant above 300 mcg; generally clinically insignificant unless doses are high and sustained
• Water retention — mild, related to GH's effect on sodium reabsorption; usually resolves within the first 2–3 weeks
• Tingling or numbness in extremities — transient, related to GH-induced nerve compression (similar to exogenous GH side effects)
• Injection site redness or irritation — technique-dependent, not specific to GHRP-2

Less common:

• Dizziness or lightheadedness shortly after injection — usually resolves quickly
• Flushing or warmth — related to GH release and vasodilation
• Headache — occasionally reported in the first few days of use

Contraindications

• Active cancer or history of cancer — elevated GH and IGF-1 can promote the growth of existing tumors. GH secretagogues should not be used by anyone with active malignancies or a recent history of cancer.
• Pituitary tumors or disorders — GHRP-2 acts directly on the pituitary. Pituitary adenomas or other pituitary conditions are contraindications.
• Diabetic retinopathy — elevated IGF-1 can worsen proliferative diabetic retinopathy by promoting neovascularization in the retina.
• Pregnancy and breastfeeding — no safety data exists for GHRP-2 during pregnancy or nursing. Avoid use entirely.
• Uncontrolled diabetes — GH is a counter-regulatory hormone to insulin. GHRP-2 may worsen glycemic control in poorly managed diabetes.

Drug Interactions

• Insulin and diabetes medications: GH opposes insulin action. Diabetic patients using GHRP-2 may need insulin dose adjustments. Monitor glucose closely.
• Corticosteroids: Both GHRP-2 and exogenous corticosteroids elevate cortisol. Concurrent use may compound cortisol-related side effects.
• MK-677 (Ibutamoren): Both act on GHS-R1a. Concurrent use is redundant and doubles ghrelin-receptor-mediated side effects (appetite, cortisol, prolactin) without proportionally increasing GH output.

When to Stop

• Persistent numbness or tingling in hands/feet that does not resolve
• Significant joint pain or carpal tunnel-like symptoms
• Signs of elevated prolactin (nipple sensitivity, gynecomastia symptoms, libido changes)
• Worsening blood glucose or signs of insulin resistance
• Any symptom that feels unusual or concerning — err on the side of caution