GHRP-2 dosage and protocol
Last reviewed Oct 7, 2026. Editorial policy
US regulatory status: FDA Category 2: significant safety risk
GHRP-2 (Growth Hormone Releasing Peptide-2) is a synthetic hexapeptide that strongly stimulates GH secretion by activating the ghrelin receptor. It produces significant GH pulses and moderate appetite stimulation. Often stacked with CJC-1295 or MOD-GRF 1-29 for synergistic GH release. One of the most studied GHRPs with decades of research backing.
- Vial size: 5 mg
- Reconstitution: 3 mL bacteriostatic water
- Concentration: 1.67 mg/mL
- Administration: subcutaneous
Research areas
- Growth Hormone
- Appetite Increase
- Muscle Growth
- Recovery
Quick start
- Reconstitute: Add 3.0 mL bacteriostatic water → ~1.67 mg/mL concentration
- Typical daily range: 100–300 mcg once daily subcutaneously
- Easy measuring: At 1.67 mg/mL, 1 unit = 0.01 mL ≈ 16.7 mcg on a U-100 syringe
- Storage: Lyophilized at −20°C; after reconstitution, refrigerate at 2–8°C and use within 2–3 weeks
Dosing protocol
| Phase | Dose | Frequency | Volume |
|---|---|---|---|
| Weeks 1–2 | 100 mcg | Once daily (SC) | 0.06 mL (6 units) |
| Weeks 3–4 | 150 mcg | Once daily (SC) | 0.09 mL (9 units) |
| Weeks 5–16 | 200 mcg | Once daily (SC) | 0.12 mL (12 units) |
How it works
GHRP-2 (pralmorelin) is a synthetic hexapeptide that activates the growth hormone secretagogue receptor (GHS-R1a), the same receptor used by the stomach hormone ghrelin. Binding in the pituitary and hypothalamus triggers a pulse of growth hormone release, and the peptide also appears to blunt somatostatin, the brake on GH secretion. Because it works through a different pathway from GHRH, combining it with a GHRH analog such as CJC-1295 or Mod GRF 1-29 produces a larger GH pulse than either alone, a synergy documented in human pharmacology studies. The GH pulse raises downstream IGF-1 production by the liver, which mediates many of GH's effects on protein synthesis, lipolysis and tissue repair. GHRP-2 is less selective than ipamorelin: human studies show modest rises in cortisol (via ACTH) and prolactin, and it stimulates appetite through ghrelin-receptor signaling, though usually less than GHRP-6. GHRP-2 has been studied in humans for decades, mostly in short-term endocrine studies, and it has been used in Japan as a diagnostic agent for GH deficiency. Long-term outcome data on body composition, performance or aging in healthy people are lacking, and it is not approved for therapeutic use in the US.
Units chart for a 5 mg vial
| Water added | Strength | 1 unit = | 100 mcg | 150 mcg | 200 mcg |
|---|---|---|---|---|---|
| 1 mL | 5 mg/mL | 50 mcg | 2 units | 3 units | 4 units |
| 2 mL | 2.5 mg/mL | 25 mcg | 4 units | 6 units | 8 units |
| 3 mL | 1.67 mg/mL | 16.7 mcg | 6 units | 9 units | 12 units |
Units on a U-100 insulin syringe (100 units = 1 mL).
Pages for each vial size and water volume
Reconstitution steps
- Draw 3.0mL bacteriostatic water with a sterile syringe
- Inject slowly down the vial wall; avoid foaming
- Gently swirl or roll until completely dissolved (do not shake)
- Label and refrigerate at 2–8°C (35.6–46.4°F), protected from light
Storage
Evidence: Common practice. What vendors and users usually do. No published stability testing supports a specific number.
- Powder or unopened: Sealed powder: freezer (about −20 °C) for long-term storage, refrigerator for weeks. Let the vial reach room temperature before opening.
- Mixed or in use: Refrigerator, 2–8 °C. Do not freeze and thaw repeatedly.
- Use within: no tested number
- Light: Keep it in the box or another dark container.
Most reconstituted peptides are kept in the refrigerator (2–8 °C) and used within about 28 days. That is a convention, not tested data: the 28 days comes from the USP <797> limit for opened multiple-dose containers, which is about sterility, not about whether the peptide stays intact.
Sources: Crestigen: Peptide storage and handling guide; USP General Chapter <797> Pharmaceutical Compounding: Sterile Preparations
Store lyophilized at −20°C in dry, dark conditions. After reconstitution, refrigerate at 2–8°C and use within 2–3 weeks. Avoid repeated freeze–thaw cycles.
Important notes
- Research use only
- Increases appetite — ideal for bulking phases
- Often used in conjunction with GHRH analogs like CJC-1295 for synergy
- Possible water retention, increased appetite, cortisol or prolactin elevation with long-term use
- Best combined with CJC-1295 or MOD-GRF 1-29 for synergistic effect
- Take on empty stomach for best GH pulse response
Supplies
- Bacteriostatic water
- Insulin syringes
- Alcohol swabs