3. GHRP2 + GHRH
The combination of GHRP2 and GHRH results in a much higher GH response than just one or the other. Let me explain GHRH real quick. In short, GHRH (growth hormone-releasing hormone) binds to GHRH receptors to trigger secretion of GH. Synthetic GHRHs replicate this and include; CJC ND, Sermorelin, etc. The most common combination here is GHRP2 + CJC ND. The exact mechanism of synergy is unknown, but my personal hypothesis is that GHRP2 may improve GH efficiency by increasing GHR (growth hormone receptor; prompts the liver to release IGF1 after binding with GH) concentration along with its effect of somatostatin (the hormone that inhibits GH) inhibition. I came to the conclusion that it may increase GHR due to it being shown to increase GHBP (growth hormone binding protein; binds to GH to increase time in bloodstream), which would be connected because GHRs “shed” GHBPs, so a higher GHR count could correlate with more GHBP. This is merely a correlation and should not be taken as causation. It’s a hypothesis and nothing else. GHRP2 also inhibits sst-1 and sst-2 mRNA expression, which basically just means it inhibits somatostatin, obviously helping GHRH produce more GH.