Symptoms of low testosterone levels in men include depression, fatigue, weakness and the loss of sex drive, according to WebMD. Testosterone levels usually begin to decline after age 30. Low testosterone levels cause the bones to lose density, increasing the chances of fractures. Normal testosterone ranges are between 300 and 800 nanograms per deciliter, but symptoms may not be evident until levels drop to the 100 to 200 nanograms per deciliter range.
Aging, medication and genetic factors contribute to low testosterone levels in men. Diseases, injuries, hormonal disorders and obesity also contribute to the condition. Problems with other hormone-producing glands, such as the thyroid, sometimes mirror low testosterone levels, reports WebMD.
Treatment options for low testosterone include injections, gels, patches and implantable pellets. For men dealing with fertility issues, the injections usually work best, advises WebMD. For other issues related to low testosterone, the gels and patches help to keep levels stable. A doctor injects the pellets under the skin of the buttocks, and they maintain levels for three to four months.
With treatment, symptoms begin to improve in a few days; however, treatment involves risks. The therapy can increase the red blood cell count and cause men to develop breasts. Treatment is not appropriate for men with breast cancer, and the medical community expresses concerns about its effect on prostate health, warns WebMD.