Side effects guide

Hexarelin Side Effects

GH secretagogue / GHRP (synthetic hexapeptide)

In human studies, hexarelin raised not only growth hormone but also cortisol and prolactin, effects that were transient and dose-related. Facial flushing and injection-site reactions are the effects most commonly described with GHRPs of this type.[1][2]

Reviewed for accuracy · Last reviewed July 8, 2026

Reported side effects

COMMONFacial flushing · Transient rise in cortisol and prolactin · Injection-site reactions
LESS COMMONWater retention · Changes in insulin sensitivity · Attenuated GH response over time (desensitization)

As a growth hormone secretagogue, hexarelin shares class-level effects discussed for this group, including water retention and changes in insulin sensitivity. Because hexarelin was never developed into an approved product, its longer-term safety in humans is not well characterized and there is no label documenting rarer risks.

A separate caveat is desensitization: the GH-releasing effect tends to attenuate with continued use. This is a pharmacological attenuation of effect rather than a classic adverse event, but it shapes how the peptide behaves over time.

Seek medical attention ifYou notice signs of an allergic reaction, chest symptoms, or persistent swelling. Hexarelin is not an approved medicine and is not medical advice.

Managing side effects

Flushing and hormone rises reported in studies were generally transient. Because hexarelin is not an approved medicine, any use is unproven and should be discussed with a doctor.

FAQ

What are the most common hexarelin side effects?Human studies describe facial flushing, transient rises in cortisol and prolactin, and injection-site reactions. GH-class effects like water retention and insulin-sensitivity changes are also discussed.
Does hexarelin affect cortisol?Yes. A dose-response study found a modest, plateauing cortisol rise alongside GH and prolactin release, consistent with other GHRPs.

References

  1. Hexarelin-Induced Growth Hormone, Cortisol, and Prolactin Release: A Dose-Response StudyJournal of Clinical Endocrinology & Metabolism · 1996 · PMID 8954038 · DOI 10.1210/jcem.81.12.8954038
  2. Growth Hormone-Releasing PeptidesEuropean Journal of Endocrinology · 1997 · DOI 10.1530/eje.0.1360445
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This page is an independent educational reference and is not medical advice, and does not indicate any approval status for any use. Talk to a doctor before starting any compound.