Growth Hormone Releasing Hexapeptide
Evidence Grade C — Moderate human evidence. 632 published studies, 231 human. 0 registered clinical trials.
GHRP-6 is one of the earliest synthetic growth hormone secretagogues, historically significant because studies of this compound led to the discovery and identification of the ghrelin receptor in 1996. It has no approval from any regulatory agency and no therapeutic clinical trials have been completed. It causes strong appetite stimulation alongside growth hormone release.
632 published studies: 231 human, 349 animal, 136 in-vitro, 26 reviews
GHRP-6 has no marketing authorisation from any regulatory agency. No therapeutic Phase III trials have been conducted. Its primary scientific significance is historical — studies of GHRP-6 and related compounds led to the identification and cloning of the ghrelin receptor (GHS-R1a) in 1996.
The compound's non-selective profile (stimulating cortisol, prolactin, and strong appetite increases alongside growth hormone) made it a less attractive clinical candidate than later, more selective secretagogues. Products available through unregulated channels lack pharmaceutical quality assurance.
Research suggests GHRP-6 activates the ghrelin receptor. It is the least selective of the major growth hormone secretagogues, producing pronounced effects on cortisol, prolactin, and appetite in addition to growth hormone release. The appetite stimulation — stronger than other compounds in this class — reflects its ghrelin-mimicking properties. These observations come from early-phase pharmacological studies.
Research suggests GHRP-6 is the least selective of the major growth hormone secretagogues, producing pronounced effects on cortisol, prolactin, and appetite in addition to growth hormone release. This non-selectivity made it a less attractive clinical candidate than later compounds like ipamorelin. Its primary value is scientific and historical — the research pathway from GHRP-6 to the ghrelin receptor's identification was a landmark in endocrinology. No human efficacy data exist for any therapeutic use. Products from unregulated channels lack pharmaceutical quality assurance.
No trials registered on ClinicalTrials.gov for this compound.
The information on this page is provided for educational and research reference purposes only. This is not medical advice. Always consult a qualified healthcare professional before making any health-related decisions.
Somatropin has been available since the mid-1980s and is one of the most established peptide therapies. It is sold under numerous brand names including Genotropin, Humatrope, Norditropin, and Omnitrope (the first biosimilar approved in the US, 2006). Approved indications include childhood and adult growth hormone deficiency, Turner syndrome, children born small for gestational age, Prader-Willi syndrome, idiopathic short stature, and short stature from chronic kidney disease. Daily injection has been the main burden of somatropin therapy, particularly for paediatric patients who may require years of treatment. This has driven the development of once-weekly alternatives (somatrogon and somapacitan), which are gradually changing the treatment landscape. Annual treatment costs remain substantial, and concerns about misuse in anti-ageing and performance enhancement contexts are ongoing.
Tesamorelin is marketed as Egrifta SV (approved November 2010) for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy. In clinical trials, it reduced visceral fat by approximately 15% compared to a 5% increase with placebo, and this reduction was sustained with continued treatment. Tesamorelin occupies a unique niche — it is the only approved GHRH analogue and the only medication specifically approved for HIV-associated lipodystrophy. Beyond its approved indication, it has attracted research interest for potential effects on liver fat, cognitive function, and peripheral neuropathy. Fat reduction reverses when treatment stops, and it is not approved for general weight loss or body composition purposes.
Somatrogon is marketed as Ngenla (approved June 2023) for paediatric growth hormone deficiency in children aged 3 years and older. In the pivotal trial, once-weekly somatrogon produced growth rates equivalent to daily somatropin injections (10.1 cm/year versus 9.8 cm/year), confirming that reducing injection frequency does not compromise growth outcomes. Ngenla represents a meaningful advance for paediatric patients and their families, reducing injections from 365 to 52 per year. Treatment adherence has been a persistent challenge with daily growth hormone, and weekly dosing is expected to improve long-term outcomes through better compliance. Somatrogon competes directly with somapacitan (Sogroya), the other approved weekly growth hormone, creating a new generation of less burdensome treatment options.
