HGH (Human Growth Hormone)

Human Growth Hormone (HGH, Somatropin) is a 191-amino acid single-chain polypeptide naturally produced by somatotroph cells in the anterior pituitary gland. HGH stimulates growth, cell reproduction, and regeneration through direct effects and indirect mechanisms via insulin-like growth factor-1 (IGF-1) production in the liver. FDA-approved indications include growth hormone deficiency in children and adults, Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, and HIV-associated wasting. Clinical effects include increased lean muscle mass, reduced body fat, improved bone density, enhanced exercise capacity, and support for tissue repair. Research continues into potential applications for aging, wound healing, and metabolic disorders. Recombinant HGH is administered via subcutaneous injection, typically daily. Side effects may include joint pain, carpal tunnel syndrome, fluid retention, and insulin resistance. Growth hormone therapy requires careful monitoring and is contraindicated in patients with active malignancy. The hormone's effects on body composition and quality of life have made it subject to misuse in anti-aging and performance enhancement contexts.

GH therapy requires careful titration and monitoring (IGF-1, glucose, bone age in children); long-term safety data for adult replacement are still maturing; 'anti-aging' or performance use is unapproved and potentially harmful; cost and access are barriers.

Administered by subcutaneous injection (daily for most somatropin products; weekly long-acting formulations now approved). After SC injection, plasma GH peaks within ~2-6 h and IGF-1 peaks ~20 h later; the elimination half-life is short (on the order of hours), which drives daily dosing. Effects are mediated primarily via hepatic and local IGF-1.