GHRP-2 and Ipamorelin are all very similar in their modes of action, they work to increase GHRP-2 (GH) levels in the human body by increasing secretion of the hormone Ghrelin. On a milligram for milligram basis they are all fairly equal in their ability to increase GH levels in the human body, with GHRP-2 being slightly more efficient.

The major differences between the 3 GHRP peptides lays in their side effects. GHRP-6 causes a significant increase in hunger for many, therefore making it good for people looking to "bulk" but no so good for those trying to lose fat. GHRP-2 is often preferred for people dieting as it does not stimulate hunger, however it does raise cortisol (a stress hormone), prolactin (a hormone which can diminish sex drive) and aldosterone (a hormone which promotes water retention) more than GHRP-6 and Ipamorelin.

Ipamorelin is similar to GHRP-6 in that it causes an increase in hunger (but it's not as dramatic as GHRP-6). However, since it does not raise cortisol, prolactin or aldosterone at recommended dosages it is a preferred choice for those who are sensitive to these hormones.