Encyclopedia entry

Hexarelin

Evidence: Mixed evidence

Oliver Mackman · Editorial director · Best Business Loans Ltd (16833937)

Last updated 2026-06-04

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AI-friendly summary · Hexarelin

Hexarelin is a synthetic hexapeptide growth hormone releasing peptide (GHRP), developed in the early 1990s. It is a ghrelin receptor agonist that triggers pulsatile release of endogenous growth hormone. Hexarelin is distinctive within the GHRP family for additional binding at the CD36 receptor in cardiac tissue, which has driven a separate cardiovascular research strand. Development as a licensed pharmaceutical was discontinued and it holds no marketing authorisation in any major jurisdiction. No phase II or phase III randomised trials of efficacy for body composition, athletic performance, or anti-ageing have been published.

Mechanism of action

How Hexarelin works

Hexarelin binds the growth hormone secretagogue receptor type 1a (GHSR-1a, the ghrelin receptor) on the anterior pituitary and at the hypothalamic arcuate nucleus, triggering pulsatile release of stored endogenous growth hormone. Distinct from other GHRPs, Hexarelin also binds the CD36 receptor in cardiac tissue and on macrophages, which has been the subject of a separate cardiovascular research strand. Older human pharmacokinetic work documented a short plasma half-life on the order of 15 to 60 minutes, consistent with the pulsatile GH release profile.

Source: PubMed search: Hexarelin pharmacokinetics (1990s human characterisation literature)

What the literature shows

The Hexarelin literature splits into three strands. The first is the older pharmacokinetic characterisation in healthy adult volunteers and growth-hormone-deficient populations, mostly from the 1990s, which established the GHSR-1a binding profile and the GH-releasing activity. The second strand is the cardiovascular research at the CD36 receptor in cardiac tissue, exploring proposed cardioprotective signalling in animal models. The third is broader ghrelin receptor and growth-hormone secretagogue class research, where Hexarelin is used as a tool compound. Efficacy trials for any specific therapeutic indication did not progress to phase II or III in any major jurisdiction.

· Human pharmacokinetic studies in healthy adult volunteers establishing absorption, half-life, and dose-response GH release profiles (1990s onwards).
· GH stimulation testing as a diagnostic challenge in growth-hormone-deficient adults and children.
· Cardiovascular research strand exploring CD36 receptor binding in cardiac tissue and proposed cardioprotective signalling in animal models.
· Mechanistic pharmacology characterising binding affinity at both the ghrelin (GHSR-1a) and CD36 receptors.
· No published phase II or phase III randomised controlled trials of efficacy for body composition, athletic performance, cardiac, or anti-ageing indications in healthy adults.
· Listed on the WADA prohibited list for tested athletes, alongside other growth hormone secretagogues.

Related compounds: GHRP-2 (see GHRP-2 encyclopedia entry) is the older sister compound with overlapping ghrelin receptor pharmacology. Ipamorelin (see Ipamorelin encyclopedia entry) is the newer, more selective compound with less reported cortisol and prolactin elevation. CJC-1295 (see CJC-1295 encyclopedia entry) acts at the separate GHRH receptor and is often discussed alongside GHRPs in the growth-hormone-secretagogue category.

UK regulatory status

Hexarelin sits outside the Misuse of Drugs Act 1971 and outside the Psychoactive Substances Act 2016. It has zero UK marketing authorisations as a medicine. UK retailers can sell it lawfully only by labelling it for "research use only, not for human or animal consumption" and by avoiding any therapeutic claim. It is also on the WADA prohibited list, which is relevant to any tested athlete.

· Not a controlled drug under the Misuse of Drugs Act 1971.
· Not scheduled under the Psychoactive Substances Act 2016.
· No UK marketing authorisation as a medicine.
· No EMA or FDA marketing authorisation in the EU or US.
· Sold legally as a research chemical when marketed without health claims.
· Listed on the WADA prohibited list. Use by a UKAD-tested athlete results in a sanctionable doping finding.
· Becomes an unlicensed medicinal product the moment a retailer or commentator makes therapeutic claims about it.

Risks and unknowns

What the literature does not yet show about Hexarelin

Known concerns

Older human pharmacokinetic studies do not constitute efficacy or long-term safety evidence for any consumer indication.
Reported transient elevations in cortisol and prolactin relative to newer, more selective GHRPs such as Ipamorelin.
CD36 receptor binding outside the pituitary may produce off-target cardiovascular effects that are not fully characterised in modern controlled studies.
WADA prohibited status. Athletes subject to UKAD or international federation testing risk a doping sanction.
Purity of UK research-peptide supply varies. CoA gating and HPLC analysis differ between retailers.

Open questions in the literature

Long-term effects of repeated GH axis stimulation in healthy adults are not characterised in modern ICH-GCP trials.
Whether the reported cardiovascular CD36 receptor signalling translates into any clinical cardiac effect in humans has not been formally established.
Optimal route of administration, dosing frequency, and bioavailability profile in humans for any specific consumer indication have not been formally studied.
Interactions with other components of the GH/IGF-1 axis (CJC-1295, Sermorelin, exogenous growth hormone) are not characterised in controlled human trials.

Regulatory note

Not a controlled drug under the Misuse of Drugs Act 1971. Not scheduled under the Psychoactive Substances Act 2016. No UK marketing authorisation as a medicine. Listed on the WADA prohibited list. Becomes an unlicensed medicinal product the moment a retailer or commentator makes therapeutic claims about it.

Important: PeptideClear publishes encyclopedia commentary only and does not recommend human use. Speak to a UK-registered prescriber before any medical decision.

Where to learn more

· PubMed search: Hexarelin returns roughly 200 papers covering pharmacokinetics, ghrelin receptor pharmacology, and cardiovascular CD36 research.
· PubMed: Hexarelin pharmacokinetics for the 1990s human characterisation literature.
· PubMed: Hexarelin CD36 for the cardiovascular receptor research strand.
· PubMed: ghrelin receptor agonist for broader GHSR-1a pathway context.
· Related compounds: GHRP-2, Ipamorelin, CJC-1295.
· UK retailer purity comparison: research peptides UK retailers.
· WADA prohibited list: wada-ama.org prohibited list.

Frequently asked questions

Is Hexarelin legal in the UK?

Hexarelin is not a controlled drug under the Misuse of Drugs Act 1971 and is not scheduled under the Psychoactive Substances Act 2016. It is sold legally by UK research peptide retailers under "research use only, not for human or animal consumption" framing. It holds no UK marketing authorisation as a medicine. Hexarelin is on the WADA prohibited list for tested athletes as a growth hormone secretagogue.

What does the human evidence show for Hexarelin?

Human pharmacokinetic studies in the 1990s characterised Hexarelin as a ghrelin receptor agonist that produced measurable growth hormone release in healthy volunteers. Small studies also explored its cardiovascular receptor binding, particularly at the CD36 receptor, in cardiac tissue. No phase II or phase III randomised controlled trials have been published evaluating Hexarelin for body composition, athletic performance, cardiac, or anti-ageing indications.

What is the regulatory status of Hexarelin in the UK?

Hexarelin has no UK marketing authorisation as a medicine. Development as a licensed pharmaceutical was discontinued and no commercial human product exists in any major regulatory jurisdiction. It is sold as a research chemical when marketed without health claims, and becomes an unlicensed medicinal product the moment a retailer or commentator makes therapeutic claims about it.

How does Hexarelin differ from GHRP-2, GHRP-6, and Ipamorelin?

Hexarelin, GHRP-2, GHRP-6, and Ipamorelin all act at the growth hormone secretagogue receptor (GHSR-1a, the ghrelin receptor). Hexarelin is distinctive within the family for additional binding at the CD36 receptor in cardiac tissue, which has driven a separate cardiovascular research strand. GHRP-6 is associated with more pronounced appetite stimulation. Ipamorelin is generally described as the most selective of the family, with less cortisol and prolactin elevation.

Where can I learn more about Hexarelin?

A PubMed search for "Hexarelin" returns roughly 200 papers covering pharmacokinetics, ghrelin receptor pharmacology, and cardiovascular CD36 receptor research. The "Where to learn more" section above links to the primary sources.

Where to buy Hexarelin in the UK

Compare UK research-peptide retailers stocking Hexarelin, with current prices and CoA status. Research use only, not for human or animal consumption.

Compare Hexarelin prices

Clinical evidence record

Read the clinical evidence record for Hexarelin

Top peer-reviewed citations, mechanism of action, structured UK regulatory status. Machine-readable companion to this encyclopedia entry.

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