Testosterone is the hormone of manliness. Yes, women make testosterone too, yet men make much more to achieve the body size, muscle mass, bone density and strength associated with manhood. Low testosterone levels contribute to infertility, loss of lean body mass, increased body fat, moodiness and even hot flashes. Yes, men have hot flashes too.
In men, testosterone is a hormone produced primarily by the testicles. As men age, testosterone levels decline. By age 30, stress, lack of exercise, highly processed foods and exposure to xenoestrogens (synthetic chemicals that have estrogenic effects like those found in pesticides) depletes testosterone levels.
In the past fifteen years the norm for blood levels of testosterone in men has dropped dramatically. Most men have no idea what their testosterone levels were when they were young and virile. By the time they seek medical attention with signs of low testosterone including erectile dysfunction, low libido, loss of muscle mass, fatigue, difficulty sleeping, and rising cholesterol levels, their testosterone has dropped significantly.
In severe cases, bio-identical testosterone replacement therapy can be prescribed by an experienced health practitioner. Yet high doses and continual use will diminish your natural ability to make testosterone.