I'm going to be using the term "testosterone" interchangeably with the word "testosterone-releasing hormone" because some products actually have two different names, but they are generally the same thing. Testosterone is the chemical that gives men and women, males and females, the strength, power, and stamina they need to run, fight, fly, swim, climb, jump, dance, etc. A person with an excessive amount of testosterone in the body can develop many physical and mental issues (not only physical but also mental). Testosterone is very important for athletic performance. In fact, most people think of testosterone as the male hormone, while testosterone-releasing hormone (TRH) is actually the female hormone, estrogen. (That's why women don't get the male hormones; they have a female body.) Testosterone-releasing hormone (TRH) is the hormone that stimulates growth of new bones, and testosterone has a strong effect on bone density. Men with low testosterone levels may suffer from many physical problems, including low energy, fatigue, loss of muscle strength, and difficulty gaining weight. (1,2,3,4) Men with high testosterone levels may also develop many problems, such as depression, aggressive behavior, increased aggression, sexual promiscuity, and a higher risk of cancer. If a man gets diagnosed with low testosterone and doesn't take any supplements, he's more likely to develop the signs of low testosterone, such as acne, low libido, or weight gain. These symptoms may persist for years.