The most specific symptoms of low testosterone in men are sexual: a lower sex drive, fewer morning erections, and trouble getting or keeping an erection. Tiredness, low mood and loss of muscle can also occur, but they have many other causes. A diagnosis needs both symptoms and blood tests, and this guide also covers the signs of high testosterone, which is more often the issue in women.
What testosterone does
Testosterone is often called the male sex hormone, but women make it too, in smaller amounts. MedlinePlus, from the U.S. National Library of Medicine, explains that in both sexes it helps control sex drive and supports muscle and bone growth. In men it is also involved in sperm production, body hair and making red blood cells.
Symptoms of low testosterone in men
Cleveland Clinic lists the sexual symptoms as the most specific:
- low sex drive;
- loss of morning or spontaneous erections;
- trouble getting or keeping an erection.
Other symptoms that strongly suggest low testosterone include loss of armpit and pubic hair, shrinking testicles, hot flashes and a low sperm count.
Less specific signs include:
- depressed mood;
- problems with concentration and memory;
- increased body fat;
- enlarged breast tissue;
- less muscle strength and endurance.
The Endocrine Society adds that, over time, low testosterone may lead to weak bones and a low red blood cell count.
Why symptoms alone are not enough
The American Urological Association (AUA) notes that the symptoms of low testosterone are “very non-specific” and can come from other conditions, such as chronic fatigue, long-term stress or depression. Its guideline says the diagnosis should be made only when a man has symptoms or signs and a low blood level.
For the blood level, the AUA recommends:
- a total testosterone below 300 ng/dL as a reasonable cut-off;
- two measurements on separate occasions, both taken early in the morning.
Timing matters because testosterone is highest in the morning. The Endocrine Society also points out that levels can drop for a while after illness, with poor nutrition, with too much exercise and with certain medications.
What causes low testosterone?
Levels fall slowly with age. The Endocrine Society puts the decline at about 1% a year after age 30, and says levels do not become severely low from age alone.
Other causes listed by MedlinePlus include problems with the testicles or pituitary gland, long-term liver or kidney disease, injury, alcohol use disorder and some genetic conditions. Cleveland Clinic notes that most men with symptoms do not have a testicle or pituitary problem. More often the cause is linked to obesity or diabetes.
Low testosterone in women
This is less clear-cut. MedlinePlus states that low testosterone levels are normal in women. Extremely low levels may point to a disorder of the adrenal glands, pituitary gland or ovaries. Tiredness or low sex drive in a woman should be assessed as a whole, not attributed to testosterone on symptoms alone.
Symptoms of high testosterone
In women, testosterone testing is mostly used when levels may be too high. MedlinePlus and Cleveland Clinic list these signs:
- excess hair on the face or body;
- acne and oily skin;
- irregular periods or no periods;
- thinning hair on the scalp in a male pattern;
- voice changes;
- difficulty getting pregnant.
Polycystic ovary syndrome (PCOS) is the most common cause. Others include adrenal gland disorders and problems with the ovaries, including tumors. Cleveland Clinic advises seeing a provider promptly if these symptoms develop rapidly, because a hormone-producing tumor is then more likely. Our post on whether acne is caused by hormones covers one of these signs in more detail.
In men, MedlinePlus lists steroid use, a tumor in the testicles and adrenal gland disorders as causes of high testosterone.
Treatment and its risks
Cleveland Clinic describes nutritious eating and physical activity as the first treatments for low testosterone. Testosterone therapy may follow if symptoms are severe or do not improve.
The Endocrine Society is clear about its limits. Testosterone therapy is recommended only for men with diagnosed hypogonadism. It is not approved by the FDA to improve strength, athletic performance or physical appearance, or to treat or prevent problems associated with ageing.
Possible risks include a high red blood cell count, acne, an increase in prostate size and reduced sperm production. The AUA says the effect on sperm production should be discussed with any man who wants children in future. It also says testosterone therapy may improve erectile function, sex drive, anemia, bone density, lean body mass and depressive symptoms, but that the evidence is inconclusive for energy, fatigue, cognitive function and quality of life.
When to see a provider
Book an assessment if sexual symptoms, unexplained tiredness or changes in body hair persist. Ask for testing in the morning, and expect a second test before any diagnosis. Our guide to the labs required for hormone therapy explains what is usually checked.
Frequently asked questions
What are the first symptoms of low testosterone?
Sexual symptoms are the most specific: lower sex drive, fewer morning erections and erection problems.
What level counts as low testosterone?
The AUA uses a total testosterone below 300 ng/dL, confirmed on two early-morning tests, together with symptoms.
Can women have low testosterone?
Low levels are normal in women. Only extremely low levels suggest an underlying disorder, according to MedlinePlus.
Next step
You can read about hormonal imbalances and testosterone replacement therapy at Beauté Medical Aesthetics, or book a consultation to discuss your symptoms and testing.
Sources
- American Urological Association. Testosterone Deficiency Guideline. Statements 1–3, 11 and 14–16.
- Endocrine Society. Hypogonadism in Men. Patient resource, 2022.
- MedlinePlus, U.S. National Library of Medicine. Testosterone Levels Test.
- Cleveland Clinic. Low Testosterone (Male Hypogonadism). Updated February 2026.
- Cleveland Clinic. Hyperandrogenism.
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