Human growth hormone (hGH, somatotropin) is a 191-amino acid protein produced by the anterior pituitary gland. Recombinant human growth hormone (rhGH, somatropin) is FDA-approved for numerous indications including pediatric and adult growth hormone deficiency, Turner syndrome, short stature from small for gestational age (SGA), Prader-Willi syndrome, chronic kidney disease, idiopathic short stature, and short bowel syndrome (Zorbtive). It is one of the most extensively studied hormones in medicine. Off-label use for anti-aging and performance enhancement is widespread but not approved, and GH is banned by WADA in sport.
Category: Hormone. Evidence rating: A (strong human clinical data).
Clinical status: FDA-approved for multiple indications. First approved in 1985 (recombinant form).
Growth hormone binds to the GH receptor (GHR), a type I cytokine receptor, activating the JAK2-STAT5 signaling pathway. This stimulates hepatic production of IGF-1, which mediates many of GH's growth-promoting effects. GH also has direct metabolic actions: it stimulates lipolysis in adipose…
Safety considerations: Common: injection site reactions, edema, joint pain (arthralgia), carpal tunnel syndrome, muscle pain (myalgia); Metabolic: glucose intolerance, insulin resistance (dose-dependent), potential progression to type 2 diabetes; Fluid retention: peripheral edema, especially at treatment initiation.
Reviewed by the PeptideAtlas Editorial Team. Last reviewed: 2026-07-05.
Pharmaceutical-grade recombinant HGH is legal with a prescription for FDA-approved indications. However, prescribing or distributing HGH for anti-aging or bodybuilding is illegal under US federal law (the 1990 Anabolic Steroids Control Act specifically restricts HGH distribution). It is WADA-banned in sport.
At replacement doses for GH deficiency, large surveillance studies (SAGhE, GeNeSIS) have not demonstrated a clear increased overall cancer risk, though some data suggest a modest increase in second neoplasms in childhood cancer survivors treated with GH. Supraphysiological doses have not been adequately studied. GH is contraindicated with active malignancy.
GH can increase lean mass and reduce fat mass in elderly individuals (Rudman et al., NEJM 1990). However, systematic reviews show these body composition changes are modest and come with frequent side effects (edema, joint pain, glucose intolerance). There is no evidence GH extends lifespan; some animal data suggest the opposite — reduced GH/IGF-1 signaling extends lifespan in model organisms.
GH deficiency is diagnosed through provocative testing (insulin tolerance test, macimorelin test, glucagon stimulation test, GHRH-arginine test) combined with clinical features and IGF-1 levels. A single random GH level is not diagnostic due to pulsatile secretion.
HGH (somatropin) is the hormone itself, injected directly to raise GH levels. Peptide secretagogues like ipamorelin, CJC-1295, and sermorelin stimulate the pituitary gland to release its own GH in a more physiological pulsatile pattern. Secretagogues maintain the hypothalamic-pituitary feedback loop, while exogenous HGH can suppress endogenous production. Secretagogues are not FDA-approved for…