Human Growth Hormone and AgingOur bodies secrete human growth hormone (HGH) at their highest levels during puberty. However, beginning in early to mid-adulthood, HGH secretion decreases at an average rate of approximately 14% per decade.1 As a result, by late adulthood total HGH secretion is typically less than half of total HGH secretion in early adultood.2 The graph below shows typical growth hormone levels versus age.
Somatopause
The decline in HGH secretion that occurs with aging is often referred to as “somatopause”. Since aging and declining HGH secretion are both associated with decreased muscle mass, bone mass, and overall strength along with increased total and abdominal fat, some hypothesize that these undesirable effects may, at least in part, be due to the decline in HGH production. Naturally, this assertion has spurred considerable interest in administering supplemental HGH as a “treatment” for aging in humans.
Limited small-scale studies have been performed to address administration of supplemental HGH as a “treatment” for aging in humans. While these studies do suggest that HGH therapy may bring about favorable body composition changes, HGH therapy has been shown to cause significant adverse side effects. In addition to these adverse side effects, other major concerns exist with regard to supplemental HGH therapy in men with growth hormone deficiency.
Human Growth Hormone Deficiency
Human growth hormone deficiency due to an age-related decline in HGH secretion is rare, even though growth hormone production certainly does decline steadily after early adulthood. Growth hormone deficiency is most commonly due to pituitary disease, pituitary tumor, radiation therapy, or trauma. While long-term HGH therapy has been evaluated for patients with deficiency due to overt pituitary disease, the long-term safety and efficacy of HGH therapy for patients with age-related HGH declines has not been evaluated.
References1. Iranmanesh A, Lizarralde G, Veldhuis JD. Age and relative adiposity are specific negative determinants of the frequency and amplitude of growth hormone (GH) secretory bursts and the half-life of endogenous GH in healthy men. J Clin Endocrinol Metab. Nov 1991; 73 (5): 1081-1088.2. O’Connor KO, Stevens TE, Blackman MR. GH and aging. In: Juul A, Jorgenson JOL, eds. Growth Hormone in Adults. Cambridge, UK: Cambridge University Press; 1996.