Your doctor will likely measure your testosterone levels at least twice before recommending testosterone therapy. Treating normal aging with testosterone therapy is not advisable. If you don't have a medical condition that's contributing to your decline in testosterone levels, your doctor might suggest natural ways to boost testosterone, such as losing weight and increasing muscle mass through resistance exercise. Could You Have Low Testosterone? Send this page to a friend To print Facebook Twitter Pinterest Testosterone is a hormone produced by the testicles. It is important for a man's sexual desire and physical appearance. Certain conditions, medications, or injuries can lead to low testosterone levels. The level of testosterone also naturally decreases with age. Low testosterone can affect Vital Alpha Testosterone. sex drive, mood, and changes in muscle and fat. Treatment with testosterone therapy can help reduce symptoms. Alternative names Male menopause; Andropause; Testosterone deficiency; Low testosterone; Androgen deficiency in man as he ages; Late-onset hypogonadism How Testosterone Affects Your Health Testosterone makes a man look and feel like a man. In men, this hormone helps: Keep bones and muscles strong Determine hair growth and location of fat on the body Produces sperm Maintain sexual desire and erections Produces red blood cells Increase energy and improve mood Causes of low testosterone Beginning in your 30s to 40s, your testosterone level can slowly begin to decline.