Testosterone levels are at their highest during adolescence and early adulthood.
In boys, the first physical signs of testosterone, or androgens, in the body are apparent during puberty. A boy’s voice changes, his shoulders broaden, and his facial structure becomes more masculine.
As men get older, their testosterone levels may decline about 1 percent per year after age 30.
In premenopausal women, testosterone is made mainly in the ovaries. Levels will decline after menopause, which usually begins between ages 45 and 55.
Signs and symptoms of low testosterone
A testosterone test measures the level of the hormone in your blood.
Some people are born with conditions that cause low testosterone levels. You may have a low testosterone level if you have an illness that causes damage to your testicles or ovaries, which make the hormone.
Levels may drop as you grow older. However, the U.S. Food and Drug Administration (FDA)advises against getting testosterone replacement therapy (TRT) for low levels caused by aging alone.
Low testosterone levels can cause changes in sexual function, including:
- reduced sexual desire, or low libido
- fewer spontaneous erections
- erectile dysfunction (ED)
Other signs of low testosterone levels include:
- changes in sleep patterns
- difficulty concentrating
- lack of motivation
- reduced muscle bulk and strength
- decreased bone density
- large breasts in men
If you feel that you may have low testosterone levels, you should see your doctor and get a test.
Testosterone and women
Testosterone is the main male hormone, but women also need it for healthy body functioning. Testosterone is found in women at much lower levels than in men.
A woman’s estrogen level drops after she enters menopause. This may make her levels of male hormones, also known as androgens, somewhat higher. Diseases such as polycystic ovarian syndrome (PCOS) can also raise testosterone levels.
Excess testosterone in a woman’s bloodstream can cause:
- loss of scalp hair
- irregular or absent menses
- growth of facial hair
Low testosterone in women can also cause fertility problems, in addition to weak bones and loss of libido.
Tests and diagnosis
The best way to diagnose low testosterone is to visit your doctor for a physical exam and a blood test.
Your doctor will look at your physical appearance and sexual development. Because testosterone levels are usually higher in the morning, the blood test should be performed before 10:00 a.m. in younger men. Men over 45 can be tested until 2:00 p.m. and still receive accurate results.
Risks associated with the blood test are rare but may include bleeding, pain at the injection site, or infection.
Effects of abnormal testosterone levels
While symptoms of lowering testosterone may be a normal part of aging, they could also be signs of other underlying factors. These include:
- a reaction to certain medications
- thyroid gland disorders
- excessive alcohol use
Testosterone levels that are lower than the normal range could be caused by conditions such as:
- cancer of the ovaries or testes
- failure of the testicles
- hypogonadism, a condition where the sex glands produce little or no hormones
- early or delayed puberty
- chronic illness, such as diabetes or kidney disease
- severe obesity
- chemotherapy or radiation
- opioid use
- genetic conditions that appear at birth, such as Klinefelter syndrome
Testosterone levels that are higher than the normal range may be caused by:
- congenital adrenal hyperplasia (CAH) in women
- testicular or adrenal tumors
If your testosterone level is too low, your doctor may suggest TRT. Testosterone is available as:
- an injection
- a patch
- gel applied to your skin
- gel applied up your nostrils
- pellets implanted under your skin
Some medications used to treat high testosterone levels in women include:
- metformin (Glucophage, Glumetz)
- oral contraceptives
- spironolactone (Aldactone)
It’s natural to be concerned about lower levels of testosterone. However, a gradual decrease is a normal part of aging. Talk to your doctor if you’re worried or experiencing abnormal symptoms.