GHRP-2 and GHRP-6
GHRP-2 and GHRP-6 are older growth-hormone-releasing peptides. They do raise growth hormone, and they also raise cortisol, prolactin and appetite. Neither is approved in the US.
- Legal lane: not FDA-approved. Sold as research chemicals; not eligible for compounding.
- Evidence grade: C
- Form: injection under the skin
- Sport: prohibited
What they are
Both are six-amino-acid peptides that imitate ghrelin, the hunger hormone, to trigger a pulse of growth hormone. GHRP-6 came first. GHRP-2, also called pralmorelin, is the stronger of the two for growth hormone and causes less hunger. Ipamorelin is a later, more selective member of the same family.
What the evidence shows
- Human studies show a growth hormone pulse within 15 to 30 minutes of an injection.
- The same studies show rises in cortisol and prolactin. One summary puts these at roughly 25% to 35% and 15% to 25%, returning to baseline within a few hours.
- In a study of healthy men, GHRP-2 increased food intake. GHRP-6 has the strongest appetite effect of the group.
- GHRP-2's only regulatory approval anywhere is in Japan, as a one-time test for growth hormone deficiency.
There are no controlled human trials showing either one improves muscle, fat, recovery or aging.
Legal status
Neither is FDA-approved, and neither is among the peptides opened up for compounding in 2026. They are sold online as research chemicals. Marketing them for human use is a red flag.
Reported dosing
No approved dose exists.
Community sources commonly cite 100 to 200 micrograms, two or three times a day, in cycles of 6 to 12 weeks. That is a description of online practice, not a studied regimen.
Safety
- Repeated cortisol and prolactin rises are the main reason clinicians moved to ipamorelin.
- Growth hormone works against insulin, so blood sugar can drift up.
- Water retention and hunger are common complaints.