Endocrinology · 7 min
GH-Axis Peptides: Secretagogues and Releasing Hormones
The two pathways
Growth hormone release is governed by two upstream signals — GHRH from the hypothalamus, acting at the pituitary GHRH receptor, and ghrelin, acting at the GHSR (growth hormone secretagogue receptor). Synthetic analogs target one or both pathways.
GHRH analogs
Tesamorelin and CJC-1295 are stabilized GHRH analogs. Tesamorelin is the most clinically studied. CJC-1295 with DAC adds a maleimide linker that binds serum albumin, extending half-life dramatically.
GHRPs and ghrelin mimetics
GHRP-2, GHRP-6, Ipamorelin, and Hexarelin act at GHSR. Ipamorelin is the most selective of the group and produces minimal effect on cortisol or prolactin in published research.
Combinations
CJC-1295 with Ipamorelin is the most frequently studied combination in the literature, pairing the two pathways for synergistic pulse amplitude.