GHRP-2 Pharmacokinetics
GHRP-2 half-life, absorption, routes of administration, and clearance.
Half-Life & Dosing Cadence
GHRP-2 has a reported elimination half-life of ~30 min. The half-life is the time it takes for blood levels to fall by half, and it's the single biggest driver of how often you dose. That's why the typical schedule lands around 1-3x daily at 100–300 mcg — frequent enough to keep levels in a useful range without stacking up. Shorter half-lives mean more frequent dosing and faster clearance if you stop; longer ones mean steadier levels but a slower washout.
Administration & Absorption
GHRP-2 is administered by subcutaneous injection (into the fat layer just under the skin). The primary route is subcutaneous. Subcutaneous delivery is absorbed steadily from the fat depot, giving smoother peaks than intramuscular dosing. Whichever route you use, rotate sites and follow sterile technique.
Reconstitution & Handling
GHRP-2 ships as a lyophilized (freeze-dried) powder that you reconstitute before use — a common starting point is a 5 mg vial with 2.5 mL of bacteriostatic water. Add the water slowly down the vial wall, swirl (don't shake), and let it fully dissolve. Reconstituted peptide is refrigerated and used within its stability window; unmixed powder keeps far longer when stored cold and dark. Always confirm exact dosing math against your own vial and concentration.
Onset & Clearance
Because of its ~30 min half-life, GHRP-2 reaches steady levels after a few consistent doses and clears the system within roughly four to five half-lives once you stop. Track how you respond over a defined block rather than judging any single dose, and give the compound enough consistent days before deciding whether it's working. This is educational information, not medical advice — review your protocol with a clinician.
Physicochemical and PK profile
- Molecular Formula
- C45H55N9O6
- Molecular Weight
- 817.97 g/mol
- CAS Number
- 158861-67-7
- Half-Life
- 15-60 minutes
- Sequence
- D-Ala-D-βNal-Ala-Trp-D-Phe-Lys-NH2
- Solubility
- Soluble in water
- Storage
- Store lyophilized at -20°C.
References
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- The combined administration of GH-releasing peptide-2 (GHRP-2), TRH and GnRH to men with prolonged critical illness evokes superior endocrine and metabolic effects compared to treatment with GHRP-2 alone. · Van den Berghe G, Baxter RC, Weekers F et al. · 2002
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- Pralmorelin - an overview | ScienceDirect Topics
- Association between overweight and growth hormone secretion in patients with non-functioning pituitary tumors. · Seki Y, Ichihara A · 2022
- Pralmorelin | C45H55N9O6 | CID 6918245 - PubChem - NIH
- Laferrere B, et al. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. Journal of Clinical Endocrinology & Metabolism. 2005;90(2):611-614. · Laferrère B, Abraham C, Russell CD, Bowers CY · 2005