Source of Growth hormone secretagogue

{{Infobox concept | name = Growth hormone secretagogue | subtitle = Research peptides | Two receptor families = GHRH receptor; ghrelin receptor (GHS-R1a) | GHRH analogues = [[Sermorelin]], [[CJC-1295]], [[Tesamorelin]] | Ghrelin-receptor agonists = [[Ipamorelin]], and related compounds | Approved example = Tesamorelin, for a specific indication }} {{medical|talk=Unapproved-compound notice}} '''Growth hormone secretagogues''' are compounds that stimulate release of endogenous growth hormone, in contrast to administration of growth hormone itself. Two receptor families are involved: the receptor for growth hormone-releasing hormone, and the ghrelin receptor GHS-R1a.{{r|sigalos2018}} GHRH analogues — [[Sermorelin|sermorelin]], [[CJC-1295|CJC-1295]], [[Tesamorelin|tesamorelin]] — mimic the hypothalamic releasing hormone. Ghrelin-receptor agonists such as [[Ipamorelin|ipamorelin]] act at a separate receptor and by a partly complementary mechanism.{{r|sigalos2018}} Because they act through the pituitary rather than replacing the hormone, the resulting secretion retains its pulsatile pattern and remains subject to negative feedback — which limits the achievable exposure and is the main pharmacological argument for the approach.{{r|sigalos2018}} == Mechanisms == GHRH-receptor agonism at somatotroph cells raises cAMP and promotes synthesis and release of growth hormone. Native GHRH has a very short half-life; the analogues are modified to extend it, and [[CJC-1295|CJC-1295]] uses a linker permitting covalent binding to albumin for a much longer duration.{{r|sigalos2018}} Ghrelin-receptor agonism acts through a different pathway and also suppresses somatostatin tone, so the two mechanisms combine more than additively in some experimental settings — the rationale for combining them that appears in community discussion.{{r|sigalos2018}} Feedback remains intact in both cases: rising growth hormone and insulin-like growth factor 1 suppress further release. This is the mechanistic reason a secretagogue cannot produce the exposures achievable with exogenous growth hormone.{{r|molitch2011}} == Evidence and status == [[Tesamorelin|Tesamorelin]] is approved for a specific indication — reduction of excess visceral adipose tissue in a defined population — and has trial evidence supporting it. Most other compounds in this group are not approved for any indication and are distributed as research chemicals.{{r|molitch2011}} The evidence base for the unapproved compounds is thin: small studies, short durations, surrogate endpoints such as growth hormone or IGF-1 concentration rather than clinical outcomes, and in several cases no controlled human data at all.{{r|sigalos2018}} They are prohibited in competitive sport under anti-doping rules, which is a regulatory fact rather than a safety statement.{{r|molitch2011}} == Material in research supply == These compounds are among the most commonly offered research peptides, and the documentary considerations are those set out at [[Certificate of analysis]] and [[Peptide content]]: a purity figure without content and water does not establish how much peptide a vial contains.{{r|usp1503}} Several are short peptides and are correspondingly easier to synthesise at high purity than the incretin analogues, which is reflected in typical reported purity figures. That is a property of the chemistry rather than of any supplier.{{r|reports}} They are not approved for human use. Nothing on this wiki is medical advice; see [[Research use only]].{{r|usp1503}} == References == {{reflist}} <ref name="sigalos2018">Sigalos JT, Pastuszak AW. "The safety and efficacy of growth hormone secretagogues." ''Sexual Medicine Reviews'' 6(1):45–53 (2018). PMID 28526632.</ref> <ref name="molitch2011">Molitch ME, Clemmons DR, Malozowski S, et al. "Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society clinical practice guideline." ''Journal of Clinical Endocrinology and Metabolism'' 96(6):1587–1609 (2011). PMID 21602453.</ref> <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> <ref name="reports">PeptidePedia Wiki community test-report tally, 2024–2026 (self-reported; see [[Project:Sourcing_guidelines]]).</ref> == See also == * [[Ipamorelin]] * [[CJC-1295]] * [[Sermorelin]] * [[Tesamorelin]] * [[Research use only]] {{DEFAULTSORT:Growth hormone secretagogue}} [[Category:Growth hormone secretagogues]] [[Category:Research peptides]] [[Category:Articles describing unapproved compounds]]