GHRP-6

GHRP-6 is the oldest compound of the three secretagogues here and its human work is correspondingly dated. A 1990 study gave the synthetic hexapeptide to 18 normal men by intravenous bolus at 0.1, 0.3 and 1.0 microgram per kilogram and measured serum growth hormone against growth hormone releasing hormone, with prolactin, luteinising hormone, thyroid-stimulating hormone and cortisol measured for specificity; mean peak growth hormone rose from 1.2 to 68.7 micrograms per litre across placebo to the highest dose. A 2013 pharmacokinetic study in nine healthy male volunteers at 100, 200 and 400 micrograms per kilogram intravenously reported a distribution half-life of 7.6 minutes and an elimination half-life of 2.5 hours. Between those two it was studied mainly as a component of a combined provocative test for adult growth hormone deficiency. Recent literature has moved to animal models of cardiac, pulmonary and renal injury.

What is not established

There is no approved indication in any jurisdiction and no established clinical outcome. The FDA states it has identified only limited safety-related information. The human record is confined to growth hormone response, pharmacokinetics and diagnostic testing, and the tissue-protection work that dominates the recent literature is entirely preclinical.

What distinguishes GHRP-6

GHRP-6 is the parent compound of the entire class: the hexapeptide first shown to release growth hormone in normal men in 1990, five years before the first somatropin approval and eight years before ipamorelin was described. Ipamorelin was derived from this scaffold by deleting the central Ala-Trp dipeptide of GHRP-1. Unlike GHRP-2 its compounding listing is not route-restricted, and unlike ipamorelin it raised plasma ACTH and cortisol in the comparative swine work, and prolactin and cortisol at the top dose in the 1990 human study.

Sources

1. Bowers CY et al. Growth hormone releasing peptide stimulates GH release in normal men and acts synergistically with GHRH. J Clin Endocrinol Metab. 1990;70(4):975-82
2. Cabrales A et al. Pharmacokinetic study of GHRP-6 in nine male healthy volunteers. Eur J Pharm Sci. 2013;48(1-2):40-6
3. Growth hormone releasing activity of GHRP-6 after short-term oral pretreatment in normal aging. Eur J Endocrinol. 1994
4. US FDA. Certain bulk drug substances for use in compounding that may present significant safety risks
5. Determination of growth hormone releasing peptide metabolites in human urine after nasal administration. Drug Test Anal. 2015

This page describes a compound as a material and summarises published research about it. It is for general and procurement information only. It is not medical advice, not a treatment recommendation, and not guidance on use. Supplied for laboratory and research use, not for human consumption.