GHRP-2

What it is

GHRP-2 (Growth Hormone Releasing Peptide-2) is a synthetic ghrelin-receptor agonist, meaning it activates the same receptor as ghrelin, the hunger-related hormone that also prompts growth hormone (GH) release. It is studied for stimulating GH release, and it also stimulates appetite.

It is often discussed alongside growth hormone-releasing hormone (GHRH) analogs such as CJC-1295, because GHRPs and GHRH act through different routes and their effects on GH release are synergistic. In the PeptidesAI encyclopedia it is categorized under growth hormone.

How it's thought to work

GHRP-2 activates the ghrelin receptor, also called the growth hormone secretagogue (GHS) receptor, to trigger GH release. Its GH-releasing activity is synergistic with that of GHRH, which is the basis for pairing it with GHRH analogs. It also mildly stimulates appetite and can raise cortisol and prolactin somewhat.

What the research says

A review of the growth hormone-releasing peptides lists GHRP-2 among the hexapeptides available for human studies and describes their GH-releasing activity as marked and dose-related. In seven lean, healthy men, an infusion of GHRP-2 increased food eaten at a buffet meal by about 36% compared with saline while GH levels rose. In Japan, a GHRP-2 stimulation test is among the tests recommended as alternatives to the insulin tolerance test for diagnosing adult growth hormone deficiency, and in a study of 71 patients with pituitary tumors it was reported to be an acceptable alternative.

GHRP-2 is not FDA-approved.

Reported side effects

The PeptidesAI encyclopedia lists increased appetite, water retention, tingling, and mild cortisol and prolactin elevation. The appetite effect has been shown in people: in the infusion study above, every participant ate more with GHRP-2 than with saline.

Reconstitution

GHRP-2 is supplied as a lyophilized (freeze-dried) powder and is typically reconstituted with bacteriostatic (BAC) water before use. It commonly comes in 5 mg and 10 mg vials. The amount of peptide in the vial is fixed; the water added only changes how concentrated the solution is.

Worked example. A 5 mg vial is 5,000 mcg. Reconstituted with 2 mL of BAC water, that works out to 5,000 mcg ÷ 2 mL = 2,500 mcg/mL. On a U-100 insulin syringe, where each unit is 0.01 mL, each unit holds 2,500 × 0.01 = 25 mcg. Use the peptide reconstitution calculator to work out the concentration and units for any vial size and water volume.

Important notes

GHRP-2 is not FDA-approved.

Sources

1. Growth hormone-releasing peptides. Ghigo E et al. Eur J Endocrinol, 1997. Review
2. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. Laferrère B et al. J Clin Endocrinol Metab, 2005. Human trial
3. The arginine and GHRP-2 tests as alternatives to the insulin tolerance test for the diagnosis of adult GH deficiency in Japanese patients: a comparison. Kinoshita Y et al. Endocr J, 2013. Human trial

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Frequently asked questions

These questions cover the same ground as the sections above, in a shorter format.

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