Hexarelin

What it is

Hexarelin is a synthetic hexapeptide developed from the same line of work that produced GHRP-6, modified to release more growth hormone per dose. On that measure it succeeded: it is the most potent of the injectable peptide secretagogues.

It also binds the CD36 receptor in cardiac tissue, which most of the others do not, and that second target is where its more interesting research has gone.

Desensitisation is the defining constraint

Every ghrelin receptor agonist blunts with continuous use. Hexarelin does it fastest.

Studies giving it repeatedly show the growth hormone response falling substantially within weeks. This is not a tolerance that a higher dose fixes, because the ceiling is receptor availability rather than agonist concentration. It is the practical reason hexarelin never became the default choice despite being the strongest option on paper, and why every reported protocol cycles it.

If the goal is sustained elevation, this is the wrong compound and MK-677 or a GHRH analogue is a better fit. If the goal is a strong pulse in a short block, this is what hexarelin is for.

The cardiac work is the more interesting literature

Hexarelin's CD36 binding gives it cardiovascular activity that appears to be independent of growth hormone entirely. Animal and cell studies report preserved cardiac function after ischaemia-reperfusion injury, reduced hypertrophy in response to angiotensin II, and effects mediated through autophagy and inflammatory pathways.

That is a genuinely promising preclinical body of work, and it is preclinical. There is no completed randomised human trial of hexarelin for a cardiac indication, and the compound has been sitting in that state for a long time, which is usually informative about how development went.

Practical notes

• Cortisol and prolactin rise meaningfully. Combined with fast desensitisation, that makes hexarelin the least appealing option for continuous use among the peptide secretagogues.
• Potency is not the useful axis. People select it for being strongest, then run into the reason nobody runs it continuously. Ipamorelin releases less growth hormone and keeps releasing it.
• The interesting research and the marketed use point in different directions. The cardiac literature is about protecting injured heart tissue in animals. It is not a reason for a healthy person to inject it for body composition.

Side effects and warning signs

Commonly reported

• Raised cortisol and prolactin, comparable to GHRP-6
• Water retention
• Increased appetite, less than GHRP-6
• Lethargy
• Blunting of the growth hormone response within weeks of continuous use

Stop and get medical help

• Any active malignancy
• Symptoms of adrenal excess with prolonged use, given the sustained cortisol elevation
• Rising fasting glucose

Sources

1. Hexarelin targets neuroinflammatory pathways to preserve cardiac function in myocardial ischemia-reperfusiontrial
2. Hexarelin protects cardiac H9C2 cells from angiotensin II-induced hypertrophy via autophagy regulationtrial

From the community

Discussion for this compound concentrates in r/Peptides.

No threads cached yet.

Reddit removed unauthenticated API access, so this section is populated by a build-time script using your own API credentials. Run pnpm fetch:reddit with REDDIT_CLIENT_ID and REDDIT_CLIENT_SECRET set.