The adrenal glands produce dehydroepiandrosterone, or DHEA, the most plentiful hormone in your bloodstream. Your body produces sufficient amounts until around age 25, but levels drop to about one-tenth of that production by age 80. DHEA is the precursor of hormones such as estrogen and testosterone. According to MedlinePlus, DHEA is used for many conditions, including to slow aging and the progression of Alzheimer's disease, help with erectile or sexual dysfunction, increase energy, aid with weight loss and increase muscle growth.
Per MedlinePlus, there is insufficient data to determine whether DHEA is effective for many of its purported uses, including building muscle mass. However, a small study conducted on participants aged 50 to 65, published in the October 1998 issue of "Clinical Endocrinology," found DHEA slightly reduced fat mass in men and gave women a modest boost in overall body mass. There is enough controversy about its effectiveness that DHEA is banned by the National Collegiate Athletic Association.
According to senior medical editor Susan Spinasanta, writing for Spine Universe, high doses of DHEA have caused liver damage in animal studies. It is also possible DHEA could stimulate the growth of hormone-based cancers.