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GHRP-2: dosage in studies

Updated 15 Oct 2026 Author: About 2 min read Drafted with the help of AI; sources and claims checked separately.

Not a recommendation, not treatment guidance. This page shows only what published human studies used, with sources. This site does not say how much anyone should use of any substance. Fimea warns against using injectable peptides bought online: Fimea warning.

GHRP-2 has no marketing authorisation in Finland, it is on Fimea's medicines list, and WADA bans it at all times (S2) [6, 7]regulator. In Japan it is approved for diagnostic use [9]B.

GHRP-2 has been given to humans as a single dose into a vein in hormone studies, under the skin for eight months to six children with growth hormone deficiency, and as a nasal spray to 15 short children for six months, six of them for 18-24 months [1, 2, 5]B. Healthy older adults received it for 30 days as a continuous infusion under the skin [8]B.

In the adult studies, GHRP-2 was a test stimulus used to study growth hormone regulation, not a treatment [3, 4]A.

Doses used in studies

Doses used in published human studies. Not a recommendation.
StudyParticipantsDoseFrequencyDurationSource and level
Pihoker 1998 (phase 1) 10 prepubertal short children, mean age 7.7 years 1 µg/kg into a vein over one minute Single dose 2 hours of follow-up [1]B
Mericq 1998 6 prepubertal children with growth hormone deficiency; no control group 0.3, then 1.0, then 3.0 µg/kg under the skin; in the fourth period 3.0 µg/kg together with GHRH (3.0 µg/kg) Daily 4 x 2 months [2]B
Pihoker 1997 15 short children, half of them with growth hormone deficiency; no control group 5-15 µg/kg as a nasal spray Twice a day for 3 months, then three times a day 6 months; 6 children 18-24 months [5]B
Moreno-Reyes 1998 (randomised order) 7 healthy young men; saline as control 1 µg/kg into a vein late at night Single dose One night [3]A
Veldhuis 2004 (randomised) 13 healthy men aged 43-71 1 µg/kg into a vein Single dose One study morning [4]A
Bowers 2004 17 healthy older women and men; saline as control 1 µg/kg per hour as a continuous infusion under the skin Continuous 30 days [8]B

Evidence levels: regulator = a regulator's assessment or decision, not research evidence · A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed

Units: µg = microgram, written mcg in the calculator. A milligram (mg) is a thousand times larger.

Notes

In the eight-month study the effect of an injection on growth hormone was brief and barely seen later in the night. The authors say treatment use would need a longer-acting formulation or route [2]B.

The half-life of a single dose into a vein was about 0.55 hours in children [1]B.

In the nasal spray study, growth velocity rose from 3.7 cm a year to 6.1 cm a year at six months, and the treatment was well tolerated. Growth was compared with the children's own baseline [5]B.

What points the other way or is uncertain

During eight months of treatment, IGF-1 and IGFBP-3 did not rise although night-time growth hormone secretion increased [2]B. With the nasal spray they did not change significantly either [5]B. In healthy older adults, by contrast, a 30-day continuous infusion under the skin raised IGF-1 and IGFBP-3 [8]B.

A dose of 1 µg/kg given late at night did not increase deep sleep although growth hormone rose; every injection was followed by a brief rise in prolactin [3]A.

More on this

Read the research yourself: sources

  1. Pihoker C, Kearns GL, French D, Bowers CY. Pharmacokinetics and pharmacodynamics of growth hormone-releasing peptide-2: a phase I study in children. J Clin Endocrinol Metab. 1998;83:1168-1172. PMID 9543135
  2. Mericq V, Cassorla F, Salazar T, et al. Effects of eight months treatment with graded doses of a growth hormone (GH)-releasing peptide in GH-deficient children. J Clin Endocrinol Metab. 1998;83:2355-2360. PMID 9661608
  3. Moreno-Reyes R, Kerkhofs M, L'Hermite-Balériaux M, et al. Evidence against a role for the growth hormone-releasing peptide axis in human slow-wave sleep regulation. Am J Physiol. 1998;274:E779-E784. PMID 9612233
  4. Veldhuis JD, Evans WS, Iranmanesh A, et al. Short-term testosterone supplementation relieves growth hormone autonegative feedback in men. J Clin Endocrinol Metab. 2004;89:1285-1290. PMID 15001624
  5. Pihoker C, Badger TM, Reynolds GA, Bowers CY. Treatment effects of intranasal growth hormone releasing peptide-2 in children with short stature. J Endocrinol. 1997;155:79-86. PMID 9390009
  6. Finland. Lääkeluettelo (Fimea medicines list), 230/2025, annex 1 ("Pralmoreliini, (GHRP-2)"). Finlex
  7. World Anti-Doping Agency. 2026 Prohibited List, section S2.2.4: "GHRP-2 (pralmorelin)". WADA
  8. Bowers CY, Granda R, Mohan S, et al. Sustained elevation of pulsatile growth hormone (GH) secretion and insulin-like growth factor I (IGF-I), IGF-binding protein-3 (IGFBP-3), and IGFBP-5 concentrations during 30-day continuous subcutaneous infusion of GH-releasing peptide-2 in older men and women. J Clin Endocrinol Metab. 2004;89:2290-2300. PMID 15126555
  9. Vodnik M, Strukelj B, Lunder M. Ghrelin receptor ligands reaching clinical trials: from peptides to peptidomimetics; from agonists to antagonists. Horm Metab Res. 2016;48:1-15. PMID 26551992

Doses are from the abstracts of the sources, read 14 Oct 2026.

Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.