CJC-1295 without DAC (Mod GRF 1-29) is a short-acting GHRH analog that binds and activates pituitary GHRH receptors to stimulate brief, pulsatile growth hormone release. Lacking the Drug Affinity Complex, it is not albumin-bound and clears within roughly half an hour, producing discrete GH pulses rather than the sustained elevation of the DAC form.

MK-677 mimics the action of ghrelin by binding to and activating the GHSR-1a receptor in the pituitary gland, stimulating pulsatile GH release. Its oral bioavailability distinguishes it from peptide-based GH secretagogues and its prolonged half-life results in sustained IGF-1 elevation. Research protocols have explored its effects on lean body mass, bone mineral density, and sleep architecture.