Both men and women make testosterone in their adrenal glands, but men also make it in their testicles and women in their ovaries. Testosterone is a sex hormone that plays an important role in your physical development, particularly your gender-related characteristics. If you're concerned about your testosterone levels, seek advice from a healthcare professional.
Function
If you're male, your testosterone levels started out low in childhood and gradually increased during puberty to eventually peak at about 40 years of age, says the University of Michigan Health System. These increases in testosterone cause you to produce sperm, grow facial hair and develop a deeper voice tone, explains the University of Pittsburgh Medical Center. In women, testosterone also supports a healthy sex drive. Around the time of menopause, women experience a reduction in hormones, including testosterone, which can decrease libido. In both sexes, testosterone levels are controlled via the luteinizing hormone secreted by the pituitary gland, and testosterone is bound to a protein in the blood known as sex hormone binding globulin, or SHBG.
Significance
Whether you're a man or a woman, you need adequate levels of testosterone to maintain proper sexual function, energy levels, muscle mass and bone density, according to the University of Michigan Health System. Testosterone also regulates fat in your body and supports your brain and cardiovascular system. In fact, testosterone is so vital to both genders that testosterone replacement therapies are commonly used to help treat certain medical problems related to low testosterone levels, says the University of Pittsburgh Medical Center. Testosterone "androgen" medications are sold under the brand names Androderm, AndroGel, Testopel, Delatestryl and First-Testosterone.
Complications
Low testosterone levels can cause a variety of health problems in both men and women. In adolescent boys, low testosterone levels can delay sexual development, notes the University of Pittsburgh Medical Center. Conversely, high testosterone levels can cause early puberty. In adult men, low testosterone can cause infertility, low libido and impotence, says the University of Maryland Medical Center. In women, low testosterone can also cause decreased libido as well as reductions in energy and irregular menstruation cycles. High testosterone levels in men and women can also cause health problems. Men with high testosterone may have prostate cancer, while women with excessive testosterone may have hirsutism, a condition where the woman develops male characteristics, explains the University of Michigan Health System. Testosterone levels in women and men can also play a role in breast cancer and osteoporosis.
Testing
If your doctor suspects that you might have inadequate or excessive testosterone levels, you might need a blood test. You could need a testosterone blood test if you're experiencing sexual dysfunction, infertility, hirsutism, early or late puberty, osteoporosis, breast or prostate cancer, or irregular menstruation, notes the University of Michigan Health System. Test results showing low testosterone levels could indicate a chronic illness, pituitary-gland problem, liver cirrhosis or alcoholism, Down syndrome, Addison's disease, or problems with the testicles or ovaries. High testosterone levels could indicate adrenal-gland cancers or abnormalities, testicular cancer, ovarian cancer, or polycystic ovary syndrome.
Warnings
Keep in mind that your test results could be altered due to different factors. For example, women taking oral contraceptives or certain estrogen-based hormone replacement therapies can show lower testosterone levels, says the University of Michigan Health System. Hyperthyroidism and obesity can also obscure the test results. Also, testosterone replacement therapies for treating low testosterone can increase your risk of breast cancer, particularly if you're a postmenopausal woman, warns the University of Pittsburgh Medical Center.
