every day, dr. mintz and many of his patients inject themselves with steroids and hormones that would get ball players banned and are considered by many to be downright dangerous. how many years have you been on human growth hormone? >> i would say probably 10 or 11. >> any adverse effects from any of this? >> none. because i'm taking very small doses. >> what have been the benefits that you've felt? >> well, energy. more energy. better body composition. my brain is working. my brain function, we tested, is actually quicker than it was five to six years ago. >> dr. mintz say substances like testosterone and human growth hormone are produced and stored by the human body. but as we get older, these natural levels taper off, creating what mintz claims are hormone deficiencies that may be responsible for some of the symptoms attributed to old age. >> we start to lose hormonal-- a lot of different hormones starting at 30, 2% to 3% a year. and by the time you're 40, you begin to recognize some changes. and we t