Ipamorelin is about as efficacious as GHRP-6 in causing GH release but even at higher dose (above 100mcg) it does not create prolactin or cortisol.
GHRP-6 at the saturation dose 100mcg does not really increase prolactin & cortisol but may do so slightly at higher doses. This rise is still within the normal range.
GHRP-2 is a little more efficacious then GHRP-6 at causing GH release but at the saturation dose or higher may produce a slight to moderate increase in prolactin & cortisol. This rise is still within the normal range although doses of 200 - 400mcg might make it the high end of the normal range.
Hexarelin is the most efficacious of all of the GHRPs at causing an increase in GH release. However it has the highest potential to also increase cortisol & prolactin. This rise will occur even at the 100mcg saturation dose. This rise will reach the higher levels of what is defined as normal.