Signs of Low Testosterone: 15 Symptoms in Men and When to Test

The most telling signs of low testosterone are sexual: less interest in sex, fewer morning or spontaneous erections, and trouble with erections. Other signs that point more clearly toward low testosterone include loss of body hair, shrinking testicles, breast tenderness, hot flashes, a low sperm count, and thinning bones. Tiredness, low mood, poor focus, weight gain and weaker muscles are common too, but have many other causes. The only way to know for sure is to combine those symptoms with two early-morning blood tests.

Below are 15 signs of low testosterone, sorted by how strongly each points to a hormone problem, plus how they differ by age, what can mimic them, and how the diagnosis is confirmed.

Short answer: the 15 signs of low testosterone

The Endocrine Society clinical practice guideline on testosterone therapy in men sorts symptoms into three groups: specific, suggestive and nonspecific. Specific and suggestive signs point more strongly to low testosterone. Nonspecific signs are real and common, but they overlap with many other health problems.

Specific and suggestive signs (stronger pointers to low testosterone):

1. Reduced sex drive (libido) and less sexual activity
2. Fewer spontaneous or morning erections, or erectile dysfunction
3. Breast discomfort or enlarged breast tissue (gynecomastia)
4. Loss of body hair, especially armpit and pubic hair
5. Very small or shrinking testes
6. Hot flashes or sweats
7. Inability to father children or a low sperm count
8. Height loss, a fracture from a minor fall, or low bone density

Less specific signs (common, but often caused by something else):

9. Low energy, motivation, drive or self-confidence
10. Feeling sad or blue, or a persistent low mood
11. Poor concentration and memory
12. Sleep problems or more daytime sleepiness
13. Mild, unexplained anemia (low red blood cell count)
14. Less muscle bulk and strength
15. More body fat and a higher body mass index

Cleveland Clinic says loss of armpit and pubic hair, shrinking testicles, hot flashes and a low or zero sperm count highly suggest low testosterone.

Low testosterone symptoms at a glance

This table sorts the main low T symptoms by Endocrine Society category, with examples of other conditions that share each one (sources cited below).

Symptom	Endocrine Society category	Can also come from (examples)
Low libido	Suggestive	Depression
Fewer morning erections or ED	Suggestive	Other medical causes a provider should check
Breast tenderness or enlargement	Suggestive	Worth evaluating on its own
Loss of armpit and pubic hair	Specific	Points more clearly to a hormone problem
Very small testes	Specific	Points more clearly to a hormone problem
Hot flashes or sweats	Suggestive	Worth evaluating on its own
Low sperm count or infertility	Suggestive	Other fertility problems
Height loss, low bone density, fracture from a minor fall	Suggestive	Other causes of bone loss
Fatigue and low motivation	Nonspecific	Hypothyroidism, depression, sleep apnea, diabetes
Low mood	Nonspecific	Depression, hypothyroidism
Poor focus and memory	Nonspecific	Depression, sleep apnea
Sleep problems or sleepiness	Nonspecific	Sleep apnea, depression
Mild unexplained anemia	Nonspecific	Needs its own workup
Less muscle and strength	Nonspecific	Hypothyroidism (weakness)
More body fat	Nonspecific	Hypothyroidism; excess weight can also lower testosterone

One large study shows why the sexual symptoms stand out. The European Male Aging Study surveyed 3,369 men aged 40 to 79 at eight European centers (New England Journal of Medicine, 2010). Fatigue, depression and trouble with vigorous activity were all linked to testosterone levels, but only three symptoms clustered consistently with low testosterone: poor morning erections, low sexual desire, and erectile dysfunction. The more of the three a man had, the lower his testosterone tended to be.

Signs of low T by age

Teens and younger men

When testosterone is low before or during puberty, the signs look different. Cleveland Clinic lists slowed growth in height, less pubic hair development, reduced growth of the penis and testicles, and less deepening of the voice. The Endocrine Society lists incomplete or delayed sexual development as a specific sign.

In younger adult men, these signs should not be put down to “just getting older.” A confirmed low result calls for a search for the cause. Possible causes named in the guideline include genetic conditions such as Klinefelter syndrome, undescended testicles, testicular injury, pituitary tumors, opioid or glucocorticoid use, and stopping anabolic steroids. If you are planning a family, raise a low sperm count or trouble conceiving early. For more detail, read our article on testosterone deficiency in young men.

Men over 40

Testosterone falls slowly with age. Cleveland Clinic says levels can drop about 1% a year starting in the late 30s. It lists these risk factors for low testosterone: age over 45, obesity, poorly managed type 2 diabetes, obstructive sleep apnea, kidney disease or cirrhosis of the liver, and HIV/AIDS. Because symptoms blend with ordinary aging and other illnesses, the sexual signs found in the EMAS study are especially useful clues. To see how your number compares with other men your age, see our testosterone levels by age chart.

What causes low testosterone (in brief)

Doctors sort low testosterone, also called hypogonadism, into two main types:

• Primary hypogonadism means the testes themselves are not making enough testosterone. Causes include Klinefelter syndrome, undescended testicles, testicular injury or infection, chemotherapy or radiation, and iron overload.
• Secondary hypogonadism means the brain’s signal is weak. The pituitary gland or hypothalamus is not telling the testes to make testosterone. Causes include pituitary problems, high prolactin, opioid use, anabolic steroid use, glucocorticoids, severe obesity, and some sleep disorders.

The Endocrine Society also separates “organic” causes, which come from disease or damage in the testes, pituitary or hypothalamus, from “functional” causes such as obesity, medications or illness, which may improve when the underlying problem is treated. Cleveland Clinic notes that most men with symptoms have neither a pituitary nor a testicular disorder. Obesity and diabetes are common underlying factors, and even a short illness can lower testosterone for a while. A blood test for luteinizing hormone (LH) helps show which type is present. Our guide to TRT blood work explains the full lab panel.

Conditions that can look like low testosterone

Many signs of low testosterone are shared with other common conditions, so a symptom list alone cannot diagnose it. A good evaluation also considers:

• Hypothyroidism (underactive thyroid). MedlinePlus lists fatigue, feeling slowed down, sadness or depression, weakness and weight gain as early symptoms. An underactive thyroid can also lower SHBG, a protein that carries testosterone in the blood. See thyroid and testosterone.
• Depression. According to MedlinePlus, depression can cause fatigue and lack of energy, loss of interest in activities including sex, trouble concentrating, and sleeping too much or too little. See low testosterone and depression.
• Obstructive sleep apnea. MedlinePlus lists waking up unrefreshed, daytime sleepiness, irritability and forgetfulness, and notes that untreated sleep apnea can lead to anxiety and depression. Cleveland Clinic lists sleep apnea as a cause of low testosterone, so the two can occur together.
• Type 2 diabetes. High blood sugar can cause fatigue, according to MedlinePlus. The Endocrine Society notes that diabetes lowers SHBG, so your total testosterone result may need a free testosterone test to interpret it.
• Medications and substances. The Endocrine Society names opioids, glucocorticoids (steroid medicines such as prednisone) and anabolic steroid use as causes of low testosterone. Cleveland Clinic adds alcohol use disorder and some medicines for prostate cancer, digestive problems and pain. Tell your provider about every medication and supplement you take.

How to tell if you have low testosterone: diagnosis

Symptoms are only half the picture. Both major guidelines say the diagnosis needs symptoms or signs together with consistently low blood levels.

• Two early-morning tests. The American Urological Association’s testosterone deficiency guideline, as summarized by the Sexual Medicine Society of North America, calls for two total testosterone tests on different occasions, drawn in the early morning, because levels change over the day. The Endocrine Society recommends fasting morning samples on two separate mornings.
• The cutoff. The AUA uses total testosterone below 300 ng/dL as the cutoff to support the diagnosis. The Endocrine Society gives 264 ng/dL as the lower limit of normal for healthy, nonobese young men, measured with assays certified to the CDC standard.
• Free testosterone when needed. The Endocrine Society recommends measuring free testosterone when total testosterone is borderline, or when a condition changes SHBG. Examples include obesity, diabetes, aging, hypothyroidism, cirrhosis and HIV.
• Finding the cause. LH helps separate primary from secondary low testosterone. Prolactin can point to a pituitary problem, according to Cleveland Clinic.

The Endocrine Society recommends against routine testosterone screening of all men. Testing is meant for men who have symptoms or signs. To see exactly what is needed before treatment can start, read our page on TRT requirements.

Can a self-check quiz tell you?

The best-known quiz is the ADAM questionnaire (Androgen Deficiency in the Aging Male). It asks 10 yes-or-no questions about energy, mood and sexual function. It counts as positive if you answer yes to lower sex drive or weaker erections, or yes to any three other questions.

The ADAM quiz flags most men who might have low testosterone, but also many who don’t. In a 2020 study of 255 men, it caught about 90% of men with low testosterone, but many men who screened positive had normal levels, and the authors concluded it cannot replace a blood test. The same paper cites an earlier study in which specificity was only 30%. The Endocrine Society says current case-finding tools lack enough sensitivity and specificity to be useful for screening. Use a quiz as a conversation starter, not a diagnosis.

When to see a provider

Consider an evaluation if any of these signs or risk factors apply to you:

• Lower sex drive, fewer morning erections or erection problems that last for weeks or months
• Breast tenderness or swelling, loss of body hair, or testicles that seem smaller
• Trouble conceiving with your partner
• A fracture from a minor fall, or a diagnosis of low bone density
• Ongoing fatigue, low mood or poor focus that rest and lifestyle changes have not fixed
• Long-term use of opioids or glucocorticoids, or stopping anabolic steroids

If low mood ever includes thoughts of harming yourself, call or text 988 right away. The 988 Suicide and Crisis Lifeline is available 24/7.

If testing confirms low testosterone, a licensed provider can explain the treatment options, including TRT online, and tailor any plan to your labs, health history and goals. If you hope to have children, say so before treatment starts. Our TRT and fertility guide explains why.

Frequently asked questions

What are the first signs of low testosterone?

For many men, the first signs are sexual: less interest in sex, fewer morning erections and weaker erections. In the European Male Aging Study, these three were most closely linked to low testosterone in men aged 40 to 79. Fatigue and low mood are common but less specific.

What testosterone level is considered low?

The American Urological Association uses a total testosterone below 300 ng/dL, measured on two early mornings, as the cutoff. The Endocrine Society uses 264 ng/dL as the lower limit of normal for healthy, nonobese young men. Either way, symptoms are also required.

Can I tell if I have low testosterone without a blood test?

No. Signs of low testosterone can raise suspicion, but many overlap with thyroid disease, depression, sleep apnea and diabetes. Only repeated morning blood tests, read alongside your symptoms, can confirm it.

Can low testosterone cause fatigue and depression?

It can contribute to both. The Endocrine Society lists low energy and low mood as nonspecific symptoms of testosterone deficiency, meaning many other conditions cause them too, so a full evaluation checks for those.

At what age does testosterone start to drop?

Cleveland Clinic says testosterone can begin falling about 1% a year in the late 30s. Age alone does not mean you have low T.

Can young men have low testosterone?

Yes. In younger men, causes can include genetic conditions, testicular injury, pituitary problems, opioid use, and stopping anabolic steroids.

Is erectile dysfunction always a sign of low T?

No. The Endocrine Society classes erectile dysfunction as suggestive, not specific, so it does not prove low testosterone. Other causes should be checked too.

Can weight, diabetes or sleep apnea lower testosterone?

Yes. Cleveland Clinic lists obesity, poorly managed type 2 diabetes and obstructive sleep apnea as risk factors for low testosterone. Our article on raising testosterone naturally covers lifestyle steps.

Should I trust an online low T quiz?

Use it only as a screening step. Studies of the ADAM questionnaire show it catches most men with low testosterone, but it also flags many men with normal levels. A blood test is still needed.

What time of day should testosterone be tested?

Early morning, when levels are highest. The Endocrine Society recommends fasting samples on two separate mornings, and the AUA also calls for two early-morning tests. Illness can temporarily lower results, so avoid testing while sick or recovering.

Talk to a licensed provider

If the signs of low testosterone on this list sound familiar, a licensed provider at MultiGen Wellness can review your symptoms, order the right morning labs and explain your results. It costs $247 to start, which includes your first provider visit, then $97 per visit. Medications are priced separately. Contact us online or call 1-800-259-0015.