Last updated: October 2026.
Quick answer: The most reliable low testosterone symptoms in men over 40 are sexual: a lower sex drive, fewer morning erections and erection problems. Fatigue, low mood, muscle loss and weight gain are common too, but have many other causes. Symptoms alone cannot confirm the diagnosis. That takes two early-morning blood tests below about 300 ng/dL.
Low testosterone symptoms tend to build slowly, which makes them easy to blame on age, work or poor sleep. Some of the 12 signs below point fairly clearly to the hormone. Others are vague and far more often caused by something else.
This guide ranks the signs by how specific they are and explains how to confirm the cause. For background on how levels change with age, see our complete guide to testosterone after 40.
Low testosterone symptoms at a glance
| Question | Short answer |
|---|---|
| Most specific signs | Low sex drive, fewer morning erections, erectile problems |
| Common but non-specific signs | Fatigue, low mood, poor concentration, muscle loss, more body fat |
| Signs of more severe deficiency | Hot flashes, loss of body hair, breast changes, low bone density, infertility |
| What counts as low | Total testosterone below about 300 ng/dL on two morning tests, with symptoms |
| Common mimics | Thyroid disease, depression, sleep apnea, anemia, medications |
| First step | A fasting, early-morning blood test ordered by a doctor |
What are the 12 low testosterone symptoms in men over 40?
The 12 low testosterone symptoms fall into three groups: sexual, physical, and mood or thinking. Having one or two does not mean your level is low. The more specific signs you have, the more worthwhile a blood test becomes.
1. Low sex drive
A lasting drop in sexual desire is the sign most closely tied to low testosterone. Stress, relationship problems and depression can cause it too.
2. Erectile problems
Low testosterone can make erections harder to get or keep. In men over 40, though, erectile dysfunction is more often caused by blood vessel disease, diabetes or medication. Our guide to what causes erectile dysfunction covers these.
3. Fewer morning erections
Erections on waking depend partly on testosterone. A clear and lasting drop in how often they happen is one of the more useful clues, because it is less affected by mood or anxiety.
4. Fatigue
Low energy is among the most reported low testosterone symptoms and also the least specific. Poor sleep, anemia, thyroid disease and depression are more common explanations.
5. Loss of muscle and strength
Testosterone helps maintain muscle, so a deficiency can lead to a gradual loss of mass and strength. Inactivity and normal ageing cause the same change.
6. More body fat
Low testosterone is linked to more body fat, especially around the waist. Excess fat also lowers testosterone, so weight gain can be a cause as well as a symptom.
7. Low mood
Low mood, irritability and loss of motivation can occur with low testosterone. These overlap heavily with depression, which is common in midlife and needs its own assessment.
8. Poor concentration
Some men describe trouble focusing or a foggy memory. The evidence tying this to testosterone is weak, and poor sleep, stress and alcohol are more likely causes.
9. Reduced body hair or shaving less
Thinner body, armpit or pubic hair, or a need to shave less often, suggests a more marked and long-standing deficiency. Scalp balding is not a sign of low testosterone.
10. Hot flashes
Sudden warmth, flushing and sweating can occur when testosterone is very low. They are best known in men on hormone-blocking treatment for prostate cancer, and are uncommon otherwise.
11. Breast tenderness or enlargement
A shift in the balance between testosterone and estrogen can cause breast tissue to grow or feel tender. This is called gynecomastia. Medications, liver disease and alcohol can also cause it, so it always needs a check.
12. Low bone density or infertility
Long-term deficiency weakens bone and may show up as a fracture after a minor fall. A low sperm count can also be the first sign of a hormone problem. Both are usually found through tests.
Which low testosterone symptoms are specific, and which are not?
Sexual symptoms and physical signs of hormone loss are the most specific, while energy, mood and body composition changes are non-specific. Guidelines give more weight to the first group when deciding who to test.
| Symptom | How specific | Common other causes |
|---|---|---|
| Low sex drive | More specific | Depression, stress, some medicines |
| Fewer morning erections | More specific | Poor sleep, blood vessel disease |
| Erectile problems | More specific | Diabetes, heart disease, medicines |
| Reduced body hair | More specific | Thyroid disease, ageing |
| Hot flashes | More specific | Infection, medicines, thyroid disease |
| Breast tenderness or enlargement | More specific | Medicines, liver disease, alcohol |
| Low bone density, infertility | More specific | Steroid tablets, smoking, testicular conditions |
| Fatigue | Non-specific | Sleep apnea, anemia, thyroid disease |
| Loss of muscle | Non-specific | Inactivity, ageing, illness |
| More body fat | Non-specific | Diet, inactivity |
| Low mood | Non-specific | Depression, stress |
| Poor concentration | Non-specific | Poor sleep, alcohol, stress |
What other conditions mimic low testosterone?
Thyroid disease, depression, sleep apnea, anemia and several medications can look just like low testosterone symptoms. A good evaluation checks for these at the same time as testosterone.
- Underactive thyroid: fatigue, weight gain and low mood. A TSH blood test checks for it.
- Depression: low mood, low libido and poor concentration. Some antidepressants also reduce sex drive.
- Obstructive sleep apnea: daytime sleepiness and loud snoring. It can also lower testosterone. See sleep and testosterone.
- Anemia: tiredness and breathlessness. Low testosterone can itself cause mild anemia.
- Medications: opioid painkillers, steroid tablets and some blood pressure and antidepressant drugs.
How do you get tested for low testosterone?
If you have low testosterone symptoms, ask a doctor for a total testosterone blood test taken in the early morning, ideally before eating. If the result is low, it must be repeated on another day before any diagnosis is made.
- Book the blood draw for early morning and skip breakfast.
- Avoid testing during an illness.
- Repeat a low result on a different morning.
- If both are low, expect LH, FSH and often prolactin tests to find the cause.
Our step-by-step guide explains how to check testosterone levels. We review home kits in best at-home testosterone test kits, but a low home result still needs a lab test.
What counts as low testosterone?
Low testosterone is usually defined as a total level below about 300 ng/dL on two separate morning tests in a man who also has symptoms. Reference ranges differ a little between labs, so use the range on your own report.
A number just under the line without low testosterone symptoms is not a diagnosis. Symptoms with normal levels are not one either. When total testosterone is borderline, or in men with obesity, doctors may measure free testosterone or SHBG.
What should you do next?
Start with testing and with the causes you can change, and leave treatment decisions until the diagnosis is confirmed. Several of the most common causes improve without hormones.
- Lose excess weight. It is the best-supported way to raise low levels in men with obesity.
- Protect your sleep and get checked for sleep apnea if you snore heavily.
- Cut back on alcohol and review your medicines with your doctor.
- Be careful with boosters. Most have weak evidence and do not replace medical care.
- Discuss TRT only after two low tests. Read TRT: is it right for you? first.
When should you see a doctor?
See a doctor if low testosterone symptoms last more than a few weeks, and sooner if one of the red flags below applies. Do not start a hormone product on your own.
- erection problems, which can be an early sign of heart disease
- a breast lump, nipple discharge or one-sided breast growth
- a lump, swelling or shrinkage in a testicle
- hot flashes, or a clear loss of body hair
- a broken bone after a minor fall
- headaches with changes in vision
- difficulty conceiving after a year of trying
Get urgent help for chest pain or for thoughts of self-harm.
Low testosterone symptoms FAQ
What are the first signs of low testosterone in men?
The earliest low testosterone symptoms are usually sexual: less interest in sex and fewer morning erections. Tiredness and low mood often appear too, but they are less reliable because many other conditions cause them.
Can you have low testosterone symptoms with normal levels?
Yes. Low testosterone symptoms such as fatigue, low mood and low libido are also caused by depression, thyroid disease, sleep apnea and medications. If two morning tests are normal, another cause is more likely.
At what level do low testosterone symptoms start?
There is no single level. Guidelines use a total testosterone below about 300 ng/dL as the usual threshold, but some men have symptoms slightly above it and others have none below it.
Does low testosterone cause erectile dysfunction?
It can contribute, but it is rarely the only cause. In men over 40, erectile dysfunction is more often linked to blood vessel disease, diabetes, medications or anxiety. A doctor should check all of these.
Does low testosterone cause weight gain?
Low testosterone is linked to more body fat and less muscle. The relationship runs both ways, because excess body fat also lowers testosterone. Losing weight often raises levels in men with obesity.
Can low testosterone cause hot flashes in men?
Yes, when levels are very low. Hot flashes are most common in men on hormone-blocking therapy for prostate cancer. In other men they are unusual and should be reported to a doctor.
Is going bald a sign of low testosterone?
No. Male pattern baldness is driven by genetics and sensitivity to a testosterone by-product called DHT. Loss of body, armpit or pubic hair is the pattern linked to low testosterone.
How do I know if my symptoms are from low testosterone or depression?
You cannot tell from symptoms alone, because the two overlap. A doctor can order morning testosterone tests and screen for depression at the same visit. Some men have both.
Bottom line
Low testosterone symptoms overlap with many common conditions, so no single sign proves the cause. Sexual symptoms are the strongest clue, and two early-morning blood tests are the only way to confirm it. Get tested, check for look-alike conditions and address weight, sleep and alcohol before you consider treatment.
References
- Endocrine Society: Testosterone Therapy in Men With Hypogonadism, clinical practice guideline.
- American Urological Association: Clinical guidelines, including Testosterone Deficiency.
- MedlinePlus: Testosterone Levels Test.
- MedlinePlus: Erectile Dysfunction.
- MedlinePlus: Hypothyroidism.
- MedlinePlus: Sleep Apnea.
This article is for information only and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease.