Growth Hormone Secretagogues: GHRH Analogs vs GHRPs in Research
Growth Hormone Secretagogues: GHRH Analogs vs GHRPs in Research
Growth hormone secretagogues are compounds that stimulate the pituitary to release growth hormone. Two distinct classes — GHRH analogs (Sermorelin, CJC-1295, Tesamorelin) and GHRPs (Ipamorelin, GHRP-2, Hexarelin) — work via different receptors. Understanding which is which is the foundation for any research using them.
The two-receptor system
Pituitary GH release is regulated by two distinct receptors: the GHRH receptor (activated by hypothalamic GHRH) and the ghrelin/GHS-R1a receptor (activated by ghrelin from the stomach).
GHRH analogs activate the first. GHRPs activate the second. Both stimulate GH release — but through different signaling cascades.
GHRH analogs: Sermorelin, CJC-1295, Tesamorelin
Sermorelin is the 29-amino-acid active fragment of native GHRH. Half-life ~10-20 minutes — preserves natural pulsatility.
CJC-1295 is a 30-amino-acid modified GHRH analog. Without DAC: ~30 min half-life. With DAC: ~8 days (binds albumin).
Tesamorelin is the full 44-amino-acid GHRH with N-terminal stabilization. The only GHRH analog with FDA approval (as Egrifta).
GHRPs: Ipamorelin and the family
Ipamorelin is the most-selective GHRP — stimulates GH release without significantly affecting cortisol or prolactin. That selectivity is what made it the GHRP of choice in modern research.
Older GHRPs (GHRP-2, GHRP-6, Hexarelin) are pharmacologically active but raise cortisol and prolactin enough to confound research focused specifically on the GH axis.
Why researchers stack them
The two classes hit different receptors via different pathways. When activated simultaneously, the combined GH release exceeds what either compound produces alone — a phenomenon researchers call GHRH + GHRP synergy.
The most-cited combinations are CJC-1295 No DAC + Ipamorelin and Tesamorelin + Ipamorelin. LiveWell offers both as pre-blended research vials.
Related at LiveWell
Sermorelin · Ipamorelin · Tesamorelin · CJC-1295 + Ipa blend · Tesa + Ipa blend
Frequently asked questions
What’s the difference between a GHRH analog and a GHRP?
GHRH analogs (Sermorelin, CJC-1295, Tesamorelin) activate the GHRH receptor. GHRPs (Ipamorelin, GHRP-2, etc.) activate the ghrelin/GHS-R1a receptor. Both stimulate GH release but through different receptor systems.
Why is Ipamorelin considered the most selective GHRP?
Unlike older GHRPs, Ipamorelin stimulates GH release without significantly elevating cortisol or prolactin. This selectivity made it the GHRP of choice in modern research.
What does GHRH + GHRP synergy mean?
When a GHRH analog and a GHRP are administered simultaneously, the combined GH release is greater than the sum of either alone. The two receptor systems amplify each other’s signaling.
For laboratory and research use only. LiveWell Peptides products are not intended for human consumption, injection, topical application, or any other administration to the human body. This article is informational and not medical advice.