What it is
Hexarelin is a synthetic hexapeptide — six amino acids — and a growth hormone secretagogue. It binds GHS-R1a, the receptor the body's own hormone ghrelin acts at, and the pituitary responds by releasing growth hormone.
It belongs to the growth hormone releasing peptide family, alongside GHRP-2 and the six-residue member of the same family — the oldest member of the group, and the one whose human pharmacology was published before trial registries existed — and it was developed in the 1990s.
An evidence base in the wrong place
This entry exists mostly to explain a contradiction anyone checking hexarelin will hit.
PubMed indexes 313 records, 192 tagged human, 27 tagged as randomized controlled trials (E-utilities, 2026-09-08). A ClinicalTrials.gov query for interventional studies naming hexarelin on the same day returned nothing at all.
The explanation is chronological. Most of hexarelin's human research was done in the 1990s, and trial registration only became a condition of publication in the major journals from around 2005. The studies are real and published; they simply predate the system people now search.
That matters because "no registered trials" reads as "untested", and here it is not. Compare two other patterns this library documents. Semax has hundreds of papers and no registry entries because the work happened in a different regulatory tradition. Follistatin has a huge human literature that measures the protein rather than administering it. Hexarelin's gap is a third thing again: real administration trials, too old to be registered.
Anyone assessing this compound has to read the 1990s literature, and most sales copy has not.
What the evidence supports
That it raises growth hormone. This is well documented in humans and not in dispute.
That raising growth hormone is a benefit. This is a separate claim and it does not come with the first. A hormone level is a measurement; muscle, recovery and body composition are outcomes. The step between them is exactly what the trials would need to establish in healthy adults, and that is not what the 1990s studies were designed to do — they were pharmacology, establishing that the compound works on the receptor as intended.
That it acts on the heart independently of growth hormone. There is a genuine research line here and it is scientifically the most interesting thing about hexarelin. It is also predominantly laboratory and animal work, and it is regularly presented in marketing as an established clinical benefit. It is not one yet.
Sport, and what testing knows
Growth hormone releasing peptides are on the WADA Prohibited List, and hexarelin is thoroughly covered.
The detection work is worth noting because of what it involved: anti-doping researchers administered these compounds to human subjects in order to identify what to screen for. A 2015 study in Drug Testing and Analysis reported urinary metabolites after nasal administration of GHRP-1, GHRP-2, GHRP-6, hexarelin and ipamorelin. So some of the more recent human administration data on this compound exists because laboratories needed to catch people using it.
How it is sold now
A 2026 review in Frontiers in Endocrinology describes this class directly: performance-enhancing drugs "marketed as 'research compounds'", with uncertainty about product composition, dose and stacking practices identified as a problem clinicians face when trying to interpret symptoms and laboratory abnormalities in people using them.
That is the current situation in one sentence. The compound is unapproved, the pharmacology is genuine, the products are unverified, and the people taking them are doing so outside any of the settings the original research was conducted in.
Where it stands
Real human pharmacology, published before trial registries existed and therefore invisible to the ordinary check. Strong evidence for the immediate effect, weak evidence for anything a person would feel, an interesting unfinished cardiac question, and no approval or label anywhere.
Related entries in this library: ipamorelin and CJC-1295 reach growth hormone by related routes and have the registry presence hexarelin lacks. The one secretagogue in this family that a regulator has approved got that approval as a diagnostic test rather than as a treatment, which is the distinction this whole group turns on. Sermorelin shows what the same goal looks like with an approval history behind it.
Last checked
2026-09-08. The PubMed counts and the ClinicalTrials.gov query were run on that date; the anti-doping and review findings are quoted from the published abstracts named above.