VialOwlLibrary / Growth hormone
GHRP-6
Also known as Growth hormone releasing hexapeptide
Human trials
Synthetic hexapeptide that stimulates growth hormone release via the ghrelin receptor and also increases appetite. Used in research and diagnostic studies in humans; not approved as a medicine.
Not an approved medicine. GHRP-6 is not an approved medicine for this use in Australia or the United States. This page summarises published research for information only. It is not a recommendation to use GHRP-6, and VialOwl does not sell or supply it.
Background
Synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) described in 1984 by Cyril Bowers and colleagues at Tulane University as the first small peptide that specifically released growth hormone. It predates the discovery of ghrelin, the natural hormone it mimics.
How it is thought to work
Activates the ghrelin receptor in the pituitary and hypothalamus, causing a short pulse of growth hormone release and a marked increase in appetite. It also raises cortisol and prolactin.
What is claimed, and the evidence
| Claim | Evidence | Notes |
|---|---|---|
| Testing pituitary growth hormone reserve | Small human studies | Studied as a diagnostic test in the 1990s; overlap between deficient and normal children limited its use. |
| Increasing appetite and weight gain | Small human studies | Appetite rise is an expected ghrelin effect; animal studies showed weight gain; no approved use. |
| Muscle growth, fat loss, healing and recovery | No published evidence | Marketed in bodybuilding and anti ageing settings; no controlled human trials for these uses. |
Side effects
| Effect | How often | Notes |
|---|---|---|
| Strong hunger | Common | Characteristic effect of GHRP-6. |
| Raised cortisol and prolactin | Common | FDA and published reviews note effects on cortisol. |
| Raised blood glucose from reduced insulin sensitivity Serious | Frequency unknown | Flagged by FDA from limited safety data. |
| Fluid retention, muscle and joint aches, injection site reactions | Frequency unknown | Reported in reviews of GH axis peptide users; frequency not measured. |
Warnings
- FDA lists GHRP-6 as posing possible immunogenicity risk and safety concerns including effects on cortisol and blood glucose.
- No long term human safety data.
- Unapproved products bought online or from compounders may be contaminated, non sterile, underdosed, overdosed or contain a different substance; the TGA warns their labelling may be inaccurate and it has received reports of severe allergic reactions and hospitalisations.
Regulatory status
- Australia
- Not included on the ARTG (unapproved). Schedule 4 in the Poisons Standard (listed by name), with Appendix D clause 5 possession controls.
- United States
- Not FDA approved. In 503A Category 3 (nominated without adequate support) and 503B Category 2 (significant safety risks).
Sources
- PubMed: On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone (1984)
- PubMed: GHRP-6 test in the diagnosis of GH deficiency
- FDA: Certain bulk drug substances for use in compounding that may present significant safety risks
- PubMed: The emerging landscape of performance-enhancing peptides modulating the GH-IGF1 axis (2026 review)
- FDA: 503A bulk drug substance categories (updated 14 May 2026)
- Poisons Standard June 2026 (Federal Register of Legislation)
Also in Growth hormone
From the VialOwl library, reviewed 26 September 2026. For education and general information. It is not medical advice and not a recommendation to use GHRP-6.