Our bodies secrete growth hormone (GH) at their highest levels during puberty. However, beginning in early adulthood (20s), GH secretion decreases at an average rate of about 15% per decade.1,2 As a result, by late adulthood total GH secretion is typically less than half of total GH secretion in early adulthood.3
In some cases, GH levels may decline by up to 50% every seven years in men.4 The graphic shows typical growth hormone levels versus age. In one study, 35% of men older than 60 years of age were GH-deficient.5
Growth Hormone and Aging: Somatopause
The decline in GH secretion that occurs with aging is referred to as “somatopause”. Since aging and declining GH secretion are both associated with decreased muscle mass, bone mass, and overall strength along with increased total and abdominal fat, some hypothesize that some of these undesirable effects may, at least in part, be due to the decline in GH production. This assertion has spurred considerable interest in administering supplemental growth hormone as a “treatment” for aging.
Limited small-scale studies have been performed to address administration of supplemental GH as a “treatment” for aging. While these studies do suggest that GH therapy may bring about favorable body composition changes, GH therapy has also been shown to cause significant adverse side effects. In addition to these adverse side effects, other major concerns exist with regard to supplemental GH therapy in men. These concerns include 1) the limited scale of studies, 2) the lack of convincing positive health outcomes, and 3) the unknown long-term link between GH therapy and cancer or other diseases.
Human Growth Hormone Deficiency
Human growth hormone deficiency due to an age-related decline in GH 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 GH therapy has been evaluated for patients with deficiency due to overt pituitary disease, the long-term safety and efficacy of GH therapy for patients with age-related GH declines has not been evaluated.
Updated: May 13, 2015
1. 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. Rudman D, Kutner MH, Rogers CM. Impaired growth hormone secretion in the adult population: relation to age and adiposity. J Clin Invest 1981; 67 (5): 1361-1369.
3. 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.
4. Giustina A, Veldhuis JD. Pathophysiology of the neuroregulation of growth hormone secretion in experimental animals and the human. Endocr Rev 1998; 19 (6): 717-797.
5. Rudman D, Feller AG, Nagraj HS, et. al. Effects of human growth hormone in men over 60 years old. N. Engl. J. Med. 1990; 323 (1): 1-6.
