In men and women, growth hormone gradually begins to decline after age of 20 years, when the body has already formed. Then, every 10 years, the amount of HGH decreases on average by 15%, but this is all individual. Therefore, starting at age of 30 years, you need to start listening to the body in order to notice the symptoms of growth hormone deficiency. Here are the main signs of low HGH level: muscle loss and gradual weight gain, low energy levels, sleep problems, decreased sex drive and sexual activity, and other common symptoms. If any of these symptoms bothers you, you need to think about growth hormone treatment. To do this, be sure to consult a doctor, get the necessary tests and then, if necessary, start treatment.