Human growth hormone, HGH, affects development and healing. Younger children with low growth hormone levels typically fail to reach normal height and weight. Older adults with HGH deficiency often have difficulty maintaining body weight and bone density. Both groups also experience a loss in muscle strength and a change in mental health. However, pharmacological and behavioral interventions can safely boost HGH levels.
Injections of recombinant HGH, a synthetic growth hormone, can increase endogenous HGH levels. Thus hormone replacement therapy using growth hormones daily is often prescribed for patients with HGH deficiency. A 2010 study published in the medical journal "Metabolism" looked at the consequences of this therapy in HGH-deficient adults. Patients receiving growth hormone injections had less body fat and lower blood sugar relative to those receiving no treatment. This shows that HGH therapy improves body composition and sugar metabolism in patients with growth hormone deficiency.
Stimulant medications, called HGH releasers, increase growth hormone levels as well. Unlike recombinant HGH, patients can take stimulant drugs by mouth and use them weekly. A 2007 paper offered in the periodical "Endocrinology" tested the experimental drug PEG-T3C. Chemists have altered this form of growth hormone so that it remained active in the body eight times longer than recombinant HGH. In the 2007 study, rats receiving PEG-T3C every third day experienced comparable increases in body weight as those receiving HGH every day. With such drugs, HGH-deficient patients can reduce the number of painful injections required by hormone replacement therapy.
Dietary intake can also boost growth hormone levels. Certain vitamins, minerals and foods may increase HGH, and thus have positive health effects. A 2010 study published in the "Journal of Pediatric Endocrinology & Metabolism" evaluated the impact of a nutritional program on HGH-deficient children. These kids were unusually small for their age, but they benefited from the program which included the intake of zinc, iron and vitamin A supplements. The effects were less than those achieved in other children taking recombinant HGH. Yet the children using the diet still experienced significant gains in height and weight. Thus a minor change in behavior can have a major impact on health.
Another behavioral intervention, exercise, may enhance natural growth hormones as well. A 2010 report in "Clinical Endocrinology" looked at HGH response to physical activity in healthy and obese adults. These subjects first performed an intense bout of exercise. This bout increased HGH levels in both groups, but more so in the healthy adults. The obese subjects then underwent a 4-week reconditioning protocol. At the end of this protocol, they again performed an intense bout of exercise. Endurance training had no effect on the growth hormone response to exercise, but endurance training combined with strength training increased HGH levels. These results suggest that obesity alters the body's hormonal system and that certain types of exercise may rectify this change.