Index by category›
Research area
Muscle & growth hormone
Peptides studied for their effects on the growth hormone / IGF-1 axis, including secretagogues and GHRH analogs explored in research contexts.
A large group of peptides act on the body's own growth hormone (GH) / IGF-1 axis, and are widely discussed in muscle, body-composition, and anti-ageing contexts. How they work is worth separating from what is proven and what is approved.
Two mechanistic families appear here. GHRH analogs (Sermorelin, CJC-1295, and Tesamorelin) mimic growth-hormone-releasing hormone. Ghrelin-receptor agonists (GHRPs) (Ipamorelin, GHRP-2, and GHRP-6) act on a separate, complementary receptor; the older GHRPs also raise cortisol, prolactin, and (notably GHRP-6) appetite, whereas ipamorelin is more selective.
What's actually approved here
Of this group, only Tesamorelin holds a current regulatory approval, and only for reducing excess visceral fat in HIV-associated lipodystrophy, not for muscle building. Sermorelin was previously FDA-approved (now discontinued). The rest are research chemicals, not approved for human use, and all are prohibited in competitive sport (WADA).
These peptides stimulate the body's own GH release rather than supplying GH directly. Robust human evidence for muscle growth or athletic benefit in healthy people is limited. See each entry for the mechanism, evidence, regulatory status, and risks. Not medical advice.
7 peptides studied in this area
CJC-1295
DAC:GRF
A synthetic tetrasubstituted analog of growth hormone-releasing hormone (GHRH 1-29) studied for prolonging GH and IGF-1 release. Exists as a long-acting albumin-binding form (with DAC) and a short-acting form (without DAC, commonly called Modified GRF 1-29).
Ipamorelin
NNC 26-0161
A synthetic pentapeptide and selective agonist of the ghrelin/growth-hormone-secretagogue receptor (GHS-R1a), studied for stimulating growth hormone release with minimal effect on ACTH, cortisol, or prolactin. Investigated clinically for postoperative ileus but discontinued; never approved for human use.
Tesamorelin
Egrifta (brand)
A stabilized synthetic analog of growth hormone-releasing hormone (GHRH 1-44), FDA-approved (brand Egrifta) to reduce excess visceral abdominal fat in HIV-associated lipodystrophy by stimulating endogenous growth hormone release.
Sermorelin
GHRH (1-29)
A synthetic 29-amino-acid peptide corresponding to the first 29 residues of human growth hormone-releasing hormone (GHRH), the shortest fully active GHRH fragment. Formerly FDA-approved (brand Geref) as a diagnostic for growth hormone secretion and as a treatment for pediatric GH deficiency, it was discontinued in the United States around 2008 for commercial reasons and is now encountered mainly through compounding pharmacies.
GHRP-2
Pralmorelin
A synthetic hexapeptide and agonist of the ghrelin / growth-hormone-secretagogue receptor (GHS-R1a) that strongly stimulates growth hormone release. Unlike the more selective ipamorelin, it also modestly raises ACTH, cortisol, and prolactin and increases appetite. Approved in Japan (as pralmorelin) only as a diagnostic agent for growth hormone deficiency; not approved as a therapeutic in the US or EU.
GHRP-6
Growth Hormone Releasing Peptide-6
A synthetic hexapeptide growth-hormone-releasing peptide and agonist of the ghrelin / growth-hormone-secretagogue receptor (GHS-R1a). One of the first GHRPs ever made, it was historically central to discovering the ghrelin receptor. It strongly stimulates a growth hormone pulse and appetite, but also raises cortisol and prolactin. It is not an approved therapeutic.
Hexarelin
Examorelin
A synthetic hexapeptide growth-hormone-releasing peptide (GHRP) and agonist of the ghrelin / growth-hormone-secretagogue receptor (GHS-R1a). It is a potent stimulus for growth hormone release but, like other GHRPs, also raises cortisol and prolactin, and it is studied for a distinctive growth-hormone-independent cardiovascular action mediated by the CD36 receptor. Reached early-phase human trials but was never approved for human use.