What it is
Hexarelin is a peptide made of 6 amino acids. It is made in a lab. It is almost the same as GHRP-6, with one amino acid swapped for a modified version. That swap makes it attach tighter to the ghrelin receptor and resist breakdown longer. It produces the highest growth hormone peak of any peptide in this class. The body stops responding to it after 4 to 6 weeks of daily use. It also attaches to a receptor on heart cells called CD36, which no other peptide in this class does. Other names: Examorelin, HEX.
What researchers study it for
- Growth hormone release
- Heart pumping strength in people
- Heart protection after heart attack in mice
- Why the body stops responding to it over time
What the studies found
1. It made human hearts pump harder within 30 minutes.
A 1999 study gave hexarelin by IV to 7 healthy men. Ejection fraction, the percent of blood the heart pushes out with each beat, rose from 64 percent to 70.7 percent. The effect peaked at 30 minutes and lasted about an hour. Blood pressure and heart rate did not change. Growth hormone itself, given the same way, did nothing to the heart. So hexarelin acts on the heart directly, not through growth hormone.
2. One oral dose in mice after a heart attack protected heart function for the long term.
A 2014 study gave mice one dose of hexarelin by mouth 30 minutes after a heart attack. Weeks later, treated mice had stronger heart pumping and less fluid in the lungs than untreated mice. Their stress hormones were lower. Mouse data only.
3. The heart effect runs through the CD36 receptor.
A 2002 study tested hexarelin in mice bred without the CD36 receptor. The heart protection disappeared. This proved the heart effect depends on CD36, a receptor on heart cells, and not on growth hormone. It is the clearest proof that hexarelin has two separate actions.
4. The whole class raises a little prolactin and cortisol, and works less with age.
A 2001 review of this peptide class in humans found the growth hormone effect is strong and repeatable, works the same in men and women, and drops with age. It also found the class raises prolactin a little, and raises ACTH and cortisol in people with Cushing's disease. Hexarelin raises cortisol more than GHRP-2 or ipamorelin.
How much research exists
Several small human studies, most on the heart. Animal studies on heart attack and growth hormone. The 4 to 6 week loss of response is well documented and is the main reason it was never developed as a drug.
Facts
- Formula: C47H58N12O6
- Weight: 887.0 g/mol
- CAS number: 140703-51-1
- Sequence: His-D-2-Me-Trp-Ala-Trp-D-Phe-Lys-NH2
- Time in the blood: 1 to 2 hours
- Storage: freeze the dry powder. Keep mixed solution in the fridge.
Legal status
Not approved by the FDA or any other agency for human use. Banned in sports by WADA under section S2.
For research use only. Not for human use. Nothing here is medical advice.