With another GH/IGF-axis medicine
Safety flag
Duplicate GH/IGF-axis stimulation may amplify IGF-1 elevation, edema, joint symptoms, and glucose intolerance.
Interaction evidence source All research profiles
Investigational GH secretagogue
GHRP-6
Prepared by the ezGLP team. Sources last checked . Profile reviewed .
Routes represented in the knowledgebase: Subcutaneous (SubQ).
Educational overview
Not FDA-approved for human use in the U.S.; long-term efficacy and safety are not established.
GHRP-6 is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) and the prototype of the growth hormone-releasing peptide family developed by Cyril Bowers and colleagues from enkephalin-derived sequences in the early 1980s. It stimulates growth hormone release by acting as an agonist at the growth hormone secretagogue receptor GHS-R1a, a receptor discovered through work on GHRP-6 several years before its natural ligand, ghrelin, was identified in 1999. Like other ghrelin mimetics it acts at both pituitary and hypothalamic sites, and it also raises ACTH, cortisol, and prolactin to a modest degree and stimulates appetite.
Human data are limited to small mechanistic and pharmacology studies from the late 1980s and 1990s. Ilson and colleagues reported in 1989 that the peptide selectively stimulated growth hormone release in healthy adults, and Bowers and colleagues showed in 1990 that it acted synergistically with growth hormone-releasing hormone in normal men. Subsequent European groups characterised its endocrine profile and its interactions with GHRH and somatostatin. There are no randomised controlled trials of GHRP-6 for any clinical indication, no long-term safety data, and no controlled evidence for the body composition, healing, or anti-aging effects for which it is marketed.
GHRP-6 has never been approved as a drug in the United States, the European Union, or comparable jurisdictions, and no pharmaceutical company has taken it beyond early research. In the United States it is sold as a compounded or research-labelled injectable. The FDA lists GHRP-6 among bulk drug substances that may present significant safety risks for compounding, citing immunogenicity risk from aggregation and peptide-related impurities and safety concerns about effects on cortisol and insulin sensitivity. The World Anti-Doping Agency names GHRP-6 explicitly on its Prohibited List under section S2.2.4, growth hormone-releasing factors, banned in and out of competition.
The compound is typically supplied as a lyophilised powder that is reconstituted with bacteriostatic water for subcutaneous injection; oral and nasal forms have also appeared but have no human stability or bioavailability data in the literature. Because no approved label exists, the supplier's or compounding pharmacy's documentation is the only formal reference for storage temperature and beyond-use dating. Dose logs for GHRP-6 usually record the lot number, reconstitution date, concentration produced, and storage conditions, and many people also note the timing relative to meals because the peptide's ghrelin-like effect on hunger is a prominent and immediate feature reported across its human studies.
- Category
- Investigational GH secretagogue
- Routes represented
- Subcutaneous (SubQ)
- Storage context
- Follow the dispensed product or pharmacy label; storage and beyond-use time vary by formulation.
Published literature
No verified PubMed or DOI link is available for this entry.
Safety evidence
Serious or important: peptide immunogenicity, aggregation, or impurity concerns.
Route-specific human safety and long-term adverse effects are not established.
Safety evidence sourceInteraction evidence
These are general, pairwise evidence notes. Green identifies the potential-synergy category, while Lv3/Lv2/Lv1 communicates evidence strength; it does not guarantee benefit or cancel a safety warning.
Common questions
Is GHRP-6 FDA approved?
No. GHRP-6 has no marketing approval from the FDA or from any other national regulator. It has been studied only in small academic physiology studies and is sold in the United States as a compounded or research-use peptide. The FDA has placed GHRP-6 in its category of bulk drug substances that may present significant safety risks in compounding, meaning the agency considers the safety information inadequate to support its routine use by compounders.
Why does GHRP-6 make people hungry?
GHRP-6 is an agonist at the ghrelin receptor GHS-R1a, the same receptor that mediates the appetite-stimulating action of the stomach hormone ghrelin. Work on GHRP-6 in fact led to the receptor's discovery in 1996, before ghrelin itself was identified. Increased hunger shortly after administration is a well-recognised feature in human studies of GHRP-6 and related peptides such as GHRP-2, and it is one of the reasons ipamorelin was developed as a more selective alternative.
What is the difference between GHRP-6 and ipamorelin?
Both are ghrelin-receptor agonists that release growth hormone, but ipamorelin was designed by Raun and colleagues in 1998 to release GH without the increases in ACTH, cortisol, and prolactin seen with GHRP-6, and it produces less hunger. GHRP-6 is the older, less selective compound. Neither has an approved indication, both are on the FDA compounding risk list, and both appear on the WADA Prohibited List.
Is GHRP-6 banned in sport?
Yes. The World Anti-Doping Agency Prohibited List names GHRP-6 as an example of a growth hormone-releasing peptide under section S2.2.4, alongside GHRP-2, hexarelin, and related compounds. Peptide hormones and releasing factors in section S2 are prohibited at all times and treated as non-specified substances, and accredited laboratories have published urine detection methods covering the GHRP family.
Further reading
- Ilson et al., J Clin Endocrinol Metab 1989 (synthetic hexapeptide selectively stimulates GH release in healthy humans)
- Bowers et al., J Clin Endocrinol Metab 1990 (GH-releasing peptide stimulates GH release in normal men, synergy with GHRH)
- Raun et al., Eur J Endocrinol 1998 (ipamorelin compared with GHRP-6 and GHRP-2)
- Sigalos & Pastuszak, Sex Med Rev 2018 (safety and efficacy of growth hormone secretagogues)
- FDA, Certain bulk drug substances for use in compounding that may present significant safety risks
- World Anti-Doping Agency, The Prohibited List (section S2.2)
Summarised from published literature for reference only, with citations to the source. Evidence is graded as reported and is not a recommendation to combine, dose, or use any compound.
For personal tracking and education only. Not medical advice, diagnosis, or treatment, and not a medical device. Peptides may be prescription-only or unapproved where you live. Consult a licensed healthcare professional.