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GHRP-6: dosage in studies

Updated 12 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-6 has been given to humans mainly in short hormone studies and growth hormone deficiency tests from 1989 to 2013. Doses were micrograms per kilogram of body weight, and most often the substance was given once into a vein [1, 6, 7]B.

In Cuban stroke trials, GHRP-6 was given in milligrams into a vein together with epidermal growth factor (EGF) twice a day for a week [8, 9]A.

Doses used in studies

Doses used in published human studies. Not a recommendation.
StudyParticipantsDoseFrequencyDurationSource and level
Ilson 1989 17 healthy men; as a control, 8 men received saline 0.05-2.5 µg/kg as a 30-minute infusion into a vein Single dose One administration [1]B
Bowers 1992, adults 5 healthy men 100 and 300 µg/kg by mouth; for comparison 0.1, 0.3 and 1.0 µg/kg into a vein Single doses Not reported [2]B
Bowers 1992, children 9 short children with growth hormone deficiency 300 µg/kg by mouth Single dose One administration, growth hormone treatment paused for 2-3 weeks [2]B
Jaffe 1993 9 healthy young men; saline as control 1 µg/kg loading dose into a vein, then 1 µg/kg per hour as an infusion into a vein Continuous infusion 34 hours [3]B
Frieboes 1995 Healthy men; the abstract does not give the number; placebo as control 50 µg into a vein Four times during the night One night [4]B
Frieboes 1999 Healthy young men; the abstract does not give the number; placebo as control 300 µg/kg by mouth as a capsule, or 30 µg/kg into the nose, or 30 µg/kg under the tongue Single dose in the evening One night [5]B
Popovic 2000 125 adults with pituitary disease and 125 healthy controls 1 µg/kg into a vein together with growth hormone releasing hormone (GHRH, 1 µg/kg) Single dose (diagnostic test) 120 minutes of sampling [6]B
Cabrales 2013 9 healthy men 100, 200 and 400 µg/kg as single doses into a vein Single doses Not reported [7]B
Hernández-Bernal 2024 (phase 1-2, randomised, open-label) 36 stroke patients: 10 + 10 received GHRP-6, 16 standard care 3.5 mg or 5 mg into a vein together with EGF (75 µg) Twice a day 7 days [8]A
COURAGE-2, Hernández-Bernal 2026 (phase 3, randomised, open-label) 188 stroke patients: 95 received the combination, 93 standard care 5 mg into a vein together with EGF (75 µg) Twice a day 7 days [9]A

Evidence levels: 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

A much larger dose was needed by mouth than into a vein: by the authors' calculation, 300 µg/kg by mouth released about the same amount of growth hormone as 1 µg/kg into a vein [2]B.

In the stroke trials GHRP-6 was always given together with EGF, so the contribution of GHRP-6 alone cannot be separated [8, 9]A.

The evidence is largely old: the hormone studies date from 1989-2000 [1, 2, 3, 4, 5, 6]B, and three of them had only 5-17 healthy volunteers [1, 2, 3]B.

What points the other way or is uncertain

The phase 3 stroke trial COURAGE-2 missed its primary endpoint: in the whole study population there was no difference from standard care in disability, daily activities or survival. Serious adverse events occurred in 30 of 95 patients in the treated group, none judged to be caused by the treatment. Possible benefit was seen mainly in the subgroup with severe strokes [9]A.

Results for doses by mouth conflict: 300 µg/kg by mouth raised growth hormone in healthy men in one study, but in another study the same dose as an evening capsule did not change growth hormone, ACTH or cortisol secretion [2, 5]B.

During the long infusion the growth hormone response to an extra GHRP-6 dose was smaller, although the authors conclude that the pituitary remained sensitive to the substance [3]B.

More on this

Read the research yourself: sources

  1. Ilson BE, Jorkasky DK, Curnow RT, Stote RM. Effect of a new synthetic hexapeptide to selectively stimulate growth hormone release in healthy human subjects. J Clin Endocrinol Metab. 1989;69:212-214. PMID 2543692
  2. Bowers CY, Alster DK, Frentz JM. The growth hormone-releasing activity of a synthetic hexapeptide in normal men and short statured children after oral administration. J Clin Endocrinol Metab. 1992;74:292-298. PMID 1730807
  3. Jaffe CA, Ho PJ, Demott-Friberg R, Bowers CY, Barkan AL. Effects of a prolonged growth hormone (GH)-releasing peptide infusion on pulsatile GH secretion in normal men. J Clin Endocrinol Metab. 1993;77:1641-1647. PMID 7903313
  4. Frieboes RM, Murck H, Maier P, et al. Growth hormone-releasing peptide-6 stimulates sleep, growth hormone, ACTH and cortisol release in normal man. Neuroendocrinology. 1995;61:584-589. PMID 7617137
  5. Frieboes RM, Murck H, Antonijevic IA, et al. Effects of growth hormone-releasing peptide-6 on the nocturnal secretion of GH, ACTH and cortisol and on the sleep EEG in man: role of routes of administration. J Neuroendocrinol. 1999;11:473-478. PMID 10336729
  6. Popovic V, Leal A, Micic D, et al. GH-releasing hormone and GH-releasing peptide-6 for diagnostic testing in GH-deficient adults. Lancet. 2000;356:1137-1142. PMID 11030292
  7. Cabrales A, Gil J, Fernández E, et al. Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers. Eur J Pharm Sci. 2013;48:40-46. PMID 23099431
  8. Hernández-Bernal F, Estenoz-García D, Gutiérrez-Ronquillo JH, et al. Combination therapy of Epidermal Growth Factor and Growth Hormone-Releasing Hexapeptide in acute ischemic stroke: a phase I/II non-blinded, randomized clinical trial. Front Neurol. 2024;15:1303402. PMID 38638315
  9. Hernández-Bernal F, Subirós-Martínez N, Gutiérrez-Ronquillo JH, et al. Phase III Open-Label, Randomized Clinical Trial of Epidermal Growth Factor and Growth Hormone Releasing Hexapeptide in Acute Ischemic Stroke. J Clin Neurosci. 2026;152:112195. PMID 42462342
  10. Dominikowski A, Rękoś Z, Olejarz M, et al. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026;17:1822475. PMID 42395176

Doses for sources 1-9 are from the abstracts. The "GHRP" in the Ilson and Bowers studies is GHRP-6 by the amino acid sequence in the abstract. Review [10] was read in full.

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