What it is
GHRP-2 is a peptide made of 6 amino acids. It is made in a lab. It attaches to the ghrelin receptor, the same receptor GHRP-6 and ipamorelin use. Of the older peptides in this class, it releases the most growth hormone per microgram. It causes less hunger than GHRP-6. Japan approved it as a hospital test for growth hormone deficiency. Other names: Pralmorelin, KP-102, Growth Hormone Releasing Peptide 2.
What researchers study it for
- Growth hormone release in adults and children
- Testing whether the pituitary gland can still make growth hormone
- Deep sleep
- Hormone timing in critically ill patients
What the studies found
1. It raised growth hormone in children in a dose-dependent way.
A 1998 phase I trial gave GHRP-2 to children. Bigger doses gave bigger growth hormone rises. It was well tolerated. The study also measured how fast it entered and left the blood. This early human data is what later got it approved in Japan as a pituitary test.
2. It did not deepen sleep.
Growth hormone naturally spikes during deep sleep, so many people assume peptides in this class improve sleep. A 1998 placebo-controlled study measured brain waves during sleep after GHRP-2. Deep sleep did not increase. This is the only controlled test of the claim, and the claim failed.
3. It re-synced three pituitary hormones in critically ill patients.
In long-term ICU patients, growth hormone, thyroid stimulating hormone, and prolactin normally rise and fall together. In these patients they had fallen out of sync. A 21-hour GHRP-2 drip brought all three back into sync. GHRH and TRH, two other hormone signals, did not do this. This suggests the body has its own GHRP-like signal that keeps pituitary hormones coordinated.
4. It raises prolactin, ACTH, and cortisol along with growth hormone.
The 1998 study that introduced ipamorelin tested GHRP-2 next to it in rats and pigs. GHRP-2 raised the stress hormones ACTH and cortisol at growth hormone releasing doses. Ipamorelin did not. GHRP-2 raises these less than GHRP-6, but it still raises them.
How much research exists
Several human studies, including work in children, healthy adults, and ICU patients. Approved in Japan for one use only: testing pituitary function. Not approved anywhere as a treatment.
Facts
- Formula: C45H55N9O6
- Weight: 818.0 g/mol
- CAS number: 158861-67-7
- Sequence: D-Ala-D-βNal-Ala-Trp-D-Phe-Lys-NH2
- Time in the blood: 15 to 60 minutes
- Storage: freeze the dry powder. Keep mixed solution in the fridge.
Legal status
Approved in Japan only as a diagnostic test for growth hormone deficiency, given by IV in a hospital. 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.