Most people think of testosterone as a male hormone, but few realize it’s also critical for women. Women typically have much smaller amounts of testosterone, but abnormally low testosterone levels can cause serious symptoms in women.
In men, most testosterone is produced in the testes. In women, testosterone is produced in various locations: about a quarter is produced in the ovaries; a quarter is produced in the adrenal glands; and the rest is produced in various other organs and tissues. A typical woman produces 0.2 to 0.3 mg/day of testosterone. Normal blood testosterone levels in females can range from 30 to 95 nanograms per deciliter (ng/dL).
As with men, testosterone levels in women peak in the 20s and slowly decline from there. By the time a woman is 40, she will usually have about 50% as much testosterone as she did earlier. This is more pronounced in women who have had surgical removal of their ovaries, which can result in overall testosterone reduction of 50% or more as a woman ages.
Causes of Low Testosterone Levels in Women
Aging is the main cause of insufficient testosterone in women, but there are other issues that can contribute to altered hormone levels. These include:
- Lifestyle factors: Obesity has been link to lower testosterone levels, thanks to higher levels of insulin, which has been shown to inhibit the production of sex hormone binding globulin (SHBG) by the liver. SHBG is used to transport sex hormones to tissues and cells. Once bound by SHBG, testosterone is not considered “free,” so higher levels of SHBG are generally associated with lower levels of free, bioactive testosterone.
- Long-term use of oral contraceptives: Oral contraception decreases circulating levels of testosterone and free testosterone by increasing SHBG. In general, as SHBG goes up, free testosterone goes down.
- Underlying medical conditions: Common diseases such as polycystic ovarian syndrome and diabetes can affect testosterone levels.
- Chemical exposure: Prolonged exposure to a chemical found in some food and plastic packaging called Bisphenol A (BPA) can lead to ovarian dysfunction in women. This can affect the testosterone production of the ovaries.
- Chronic stress: Prolonged stress affects the testosterone levels by reducing overall production of testosterone.
Effects of Low Testosterone in Women
Women with low testosterone levels can experience a sudden drop in their energy levels. They may have a hard time getting out of bed in the morning or may feel drained. Physical activities may leave them exhausted.
Low levels of testosterone in women can also cause sleep deprivation through insomnia or other sleep disturbances.
Many women with low testosterone suffer from unexplained weight gain. Testosterone plays a role in fat distribution, so low levels are associated with a sudden increase in body fat, particularly dangerous abdominal fat.
Also, testosterone functions to maintain the bone density. Insufficient testosterone can lead to bone deterioration and osteoporosis, which increases the risk of fractures.
Other physical changes include hair loss, irregular menstruation, and decreased desire for sex. Aside from these physical changes, low testosterone levels can also cause emotional changes such as depression, anxiety, and a decreased sense of well-being.
While these symptoms could all be caused by low testosterone, they could also be signs of various underlying factors such as a reaction to certain medications, thyroid gland disorders, mental problems, and excessive use of alcohol and illicit drugs. If you suspect your testosterone levels are low, consult with a qualified physician about testosterone testing and possible hormone therapy or lifestyle modifications.
