Growth Hormone

Growth hormone (GH), also known as human growth hormone (HGH) or somatotropin, is a peptide hormone produced by the anterior pituitary gland in the brain. As its name suggests, GH is essential for normal growth and development during childhood and adolescence — it stimulates the growth of bones, cartilage, and muscles. However, GH continues to play important roles throughout adult life, influencing metabolism, body composition, bone density, muscle mass, immune function, and tissue repair.

GH is released in pulses throughout the day, with the largest bursts occurring during deep sleep (particularly during the first few hours of the night) and during intense exercise. GH secretion is regulated by two hypothalamic hormones: growth hormone-releasing hormone (GHRH), which stimulates release, and somatostatin, which inhibits it. Once released, GH stimulates the liver to produce insulin-like growth factor 1 (IGF-1), which mediates many of GH's effects on tissues throughout the body.

GH production naturally declines with age — a phenomenon sometimes called 'somatopause.' Starting around age 30, GH secretion decreases approximately 14% per decade. This decline has fueled interest in GH supplementation as an anti-aging intervention, though synthetic GH is FDA-approved only for specific medical conditions including childhood GH deficiency, adult GH deficiency, and muscle-wasting associated with HIV/AIDS. Off-label use of GH for anti-aging or athletic performance enhancement is not recommended due to potential side effects.

GH deficiency in children causes short stature and delayed development, while adult GH deficiency can manifest as increased body fat, decreased muscle mass, reduced bone density, fatigue, and impaired quality of life. Diagnosis involves GH stimulation tests and measurement of IGF-1 levels.

For adults with documented GH deficiency, replacement therapy can improve body composition, bone density, energy levels, and quality of life. However, the use of GH in individuals with normal levels is not recommended and carries risks including insulin resistance, fluid retention, and potentially increased cancer risk.