Growth Hormone (GH) replacement therapy dosed to normalize IGF-I levels may be an effective adjunct to lifestyle modification in a "clinically necessary" weight loss program for obese adults.
The goal of all weight loss programs is to lose body fat but retain lean body mass such as muscle,but what happens is that when people go on a diet, after a while, they stop losing weight. Low levels of GH, known to occur with obesity, may be to blame. When GH is low, the body tends to accumulate body fat and lose muscle, and energy levels are low.
Past studies of GH replacement in obesity have involved extremely high doses of GH, which were found to have side effects. Researchers tested the effects of adding a low-dose of GH to lifestyle modification in the treatment of obese patients.The dose of GH was calculated to replace the normal amount the body would make if the patients were not obese. Researchers randomized 59 obese subjects 20 to 45 years of age, to exercise, a calorie-restricted diet, and either human GH or placebo administered by nightly injections for six months. Thirty-nine completed the protocol.
After 6 months, subjects in the GH arm had lost about 5 pounds and the shed pounds did not return during the 3-month GH-free follow-up period. Importantly,the weight loss was entirely made up of body fat, largely in the abdominal area. The patients did not lose any muscle mass. Weight loss in the control arm was not significant. Changes in body fat in the GH arm correlated with normalization of IGF-I levels.
GH-treated subjects also exhibited a 19% increase in HDL cholesterol, which may have a long-term benefit in protecting these people from heart disease. GH therapy did not alter LDL, VLDL, triglycerides, glucose, insulin, insulin sensitivity, resting energy expenditure or blood pressure. GH therapy was well tolerated with only one subject discontinuing due to edema.
The reason for loss of weight has not been known, whether they lost weight because they had a decrease in appetite or whether they kept up their muscle mass and hence were able to exercise is still in question. However GH does not replace the need for diet and exercise but may help people maintain these methods for weight loss.