Growth hormone releasing hormone (GHRH) is a natural hormone which works synergistically with ghrelin to stimulate pulses of GH production. GHRH is itself not usable as a drug, but has been modified to produce the derivatives CJC-1295 and Modified GRF 1-29 (also called “CJC-1295 without DAC.”)
CJC-1295 is quite long-acting, while Mod GRF 1-29 has a half-life of about 30 minutes. This may be better, but good results certainly have been had with CJC-1295 as well.
An example use is 100 mcg of Mod GRF 1-29 together with 100 mcg of a GHRP three times per day, preferably about 30 minutes before meals.
This usage probably produces more GH than does use of a GHRP alone. When specifically desiring this, for example because of being focused on body composition changes and personally being able to tolerate higher GH levels, this could be preferred to using only GHRP.
I don’t think there would be an advantage for this (or any) application compared to combining a GHRP with hGH.
It might be better to use just a larger amount of a GHRP, such as 150-200 mcg of GHRP-6 three times per day, where the goal was improved healing from injuries. This is because the GHRP itself may contribute to healing, whereas there’s much less evidence for a GHRH doing so.
Why not just use the larger amount of GHRP-6 and also use the Mod GRF 1-29 or CJC-1295 at 100 mcg dosings?
Well, perhaps you could, but I don’t have a basis for saying that that is okay. It’s just an unknown to me. If the GH effect resulting from 100 mcg of GHRP-6 and a GHRH isn’t as much as you want, then I’d rather you add hGH to it rather than go to such a very high level of pituitary stimulation.