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Terminus Peptides
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Research profile · Peptide

Hexarelin

Also known as Hexarelin acetate, Examorelin

Early human — evidence level 3 of 4: Early human evidenceExperimental — UK regulatory status: Experimental — not authorised for human use in the UK

Overview

A synthetic hexapeptide growth hormone secretagogue with a documented decline in response over repeated administration.

Category
Peptide
Highest evidence level identified
Early human evidence
Last scientifically reviewed
20 August 2026
Last regulatory review
20 August 2026

Mechanism under investigation

Hexarelin is a synthetic hexapeptide growth hormone secretagogue, structurally a modified analogue of GHRP-6, acting as an agonist at the growth hormone secretagogue receptor. It is also reported to bind CD36, a scavenger receptor expressed in the myocardium, and this second target is proposed to mediate cardiac effects that appear independent of growth hormone. The relative contribution of the two receptors is not fully resolved.

Research areas

  • Pituitary endocrinology
  • Cardiac models

These are fields in which the compound has been investigated. Listing a field is not a statement that anything was demonstrated within it.

Current evidence

In-vitro evidence

Cells, tissues or biochemical systems outside a living organism.

Present. Work includes receptor-level characterisation and studies of growth hormone release from cultured pituitary cells and tumour tissue. Rapid receptor desensitisation has also been described in vitro.

Animal evidence

Studies in living non-human animals.

Extensive, particularly cardiac. Rodent models report reduced infarct size, inhibition of cardiomyocyte apoptosis, attenuation of fibrosis and ventricular remodelling, and protection in ischaemic kidney injury. Cardioprotection independent of growth hormone has been demonstrated in rats.

Human observational evidence

Studies observing people without assigning an intervention.

Effectively absent. No cohort or registry data were located. Human-facing literature is analytical, covering detection of metabolites in urine.

Clinical-trial evidence

Studies assigning an intervention to human participants.

Present and, for cardiac endpoints, better than for the other peptides in this class — but very small. Acute administration increased left ventricular ejection fraction in growth-hormone-deficient patients and controls without altering blood pressure or cardiac output, and a comparison against recombinant growth hormone in seven male volunteers found only hexarelin raised ejection fraction. In patients with severe left ventricular dysfunction the effect appeared in the ischaemic but not the dilated cardiomyopathy group. No registered trials exist.

Study limitations

  • Human cardiac studies are extremely small — seven to sixteen participants — and measured acute, short-lasting changes in ejection fraction rather than clinical outcomes such as symptoms, hospitalisation or survival.
  • Response declines with repeated administration. This is documented in humans: over sixteen weeks the reduction in growth hormone response against baseline was significant, and a separate study found lower peak secretion on a second administration two hours after the first.
  • In that sixteen-week study the attenuated response was accompanied by no meaningful change in IGF-I, body composition or bone mineral density — a measurable hormone spike did not translate into a measurable downstream effect.
  • The large cardioprotection literature is overwhelmingly animal and in vitro; the review consolidating it states clinical trials are still warranted.

UK regulatory context

Experimental — not authorised for human use in the UK

A compound appearing in research literature that holds no UK authorisation for human use in any indication.

Source: The Human Medicines Regulations 2012, regulation 46 — prohibition on sale or supply of an unauthorised medicinal product (opens legislation.gov.uk in a new tab) (legislation.gov.uk)

Regulatory classification is jurisdiction-specific. A compound authorised elsewhere is not thereby authorised in the UK, and a supplier’s description of a substance does not determine how it is classified in law. See safety and regulation for the framework and the authoritative sources.

Safety and interpretation

Acute administration in small supervised studies was reported without adverse haemodynamic effects, but these were single-occasion exposures in monitored settings. A 2026 review attributes altered sleep architecture with reduced slow-wave sleep, and stimulation of multiple endocrine axes, to this compound. The documented decline in response over repeated administration, combined with the absence of long-term controlled safety data, means the risk profile of sustained use is not established.

References