Key Takeaways
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Tired even after a full night's sleep? Less interested in sex than you used to be?
These could be low testosterone symptoms. But not every sign means your testosterone is low.
Testosterone is the main male sex hormone. It supports sex drive, muscle, bones, and red blood cells. Levels drop slowly with age, and when they fall too low, doctors call it low testosterone (low T).
Only about 5.6% of men have both low T and symptoms. 1 This blog explains which signs matter most, how testing works, and when to see a doctor.
Low Testosterone Symptoms: The 10 Signs in Men
The symptoms of low testosterone in men often build slowly, so they're easy to miss. Doctors call the condition hypogonadism. We've grouped the signs by how closely research links them to low T.2
Sexual Signs: The Clearest Clues of Low T
1. Low sex drive
Your libido, or desire for sex, is the sign most closely tied to low T. A small dip with age is normal. A clear drop that doesn't feel like you is worth checking.
2. Fewer morning erections
Most healthy men wake up with an erection a few times a week. If that has mostly stopped, it can be an early clue.
3. Trouble getting or keeping an erection
Erectile dysfunction (ED) is linked to low T, but it has many other causes. Diabetes, heart disease, stress, and some medicines are just as common. So, ED alone doesn't prove low testosterone.
4. Smaller testicles or less body hair
Testosterone keeps your testicles at their normal size. It also supports armpit, pubic, and facial hair. Slowly losing either is a sign doctors take seriously.
5. Hot flashes
Sudden waves of heat and sweat aren't only a woman's problem. In men, they usually show up when testosterone is very low.3
6. Constant tiredness
Feeling worn out is one of the most common complaints. But poor sleep, thyroid problems, and depression cause it too. On its own, it's a weak sign.
7. Losing muscle and strength
Testosterone helps you build and keep muscle. You may find it harder to get stronger at the gym, even with the same routine.
8. More belly fat or breast tissue
Low T makes your body store more fat, mostly around the waist. Some men also get swollen breast tissue, called gynecomastia.
9. Mood changes and brain fog
Men with low T often feel cranky, flat, or less driven. Some pull away from friends or find it hard to focus.
10. Weaker bones and low blood count
You usually find these on tests, not by feeling. Low T can weaken your bones (osteoporosis) and lower your red blood cells (anemia).
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Why sexual symptoms matter most A study of over 3,000 men aged 40 to 79 found only three symptoms clearly tracked with low T: low sex drive, fewer morning erections, and erection problems. Tiredness and low mood were only weakly linked. |
Signs of Low Testosterone in Men vs. Lookalike Conditions
Many of these signs overlap with other health problems. Check this table before you blame your hormones.4
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Symptoms |
Link to Low T |
Other Common Causes |
Does Testosterone Treatment Help? |
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Low sex drive |
Strong |
Stress, depression, medicines |
Yes |
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Fewer morning erections |
Strong |
Poor sleep, blood vessel problems |
Often |
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Erectile dysfunction |
Moderate |
Diabetes, heart disease, anxiety |
Small improvement; results vary across trials |
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Smaller testicles, less body hair |
Strong |
Past steroid use |
No, it can shrink testicles more |
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Hot flashes |
Strong (very low T) |
Anxiety, thyroid, medicines |
Yes |
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Tiredness |
Weak |
Sleep apnea, thyroid, anemia |
Not proven |
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Muscle loss |
Moderate |
Inactivity, aging |
Builds muscle size |
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Belly fat, breast tissue |
Moderate |
Weight gain, medicines |
Lowers body fat slightly; doesn’t reverse breast tissue |
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Mood, brain fog |
Weak |
Depression, stress, poor sleep |
Slight mood boost |
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Weak bones, anemia |
Moderate |
Low iron or vitamin D |
Improves test results |
How to Tell If You Have Low Testosterone
Symptoms alone can't confirm low T. You need a simple blood test, called a total testosterone test, done the right way.
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Write down your symptoms and how long you've had them.
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Get tested before 10 a.m., when your levels are highest.
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Repeat the test on a different morning. One low result isn't enough.
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Doctors diagnose low T when both results are below 300 ng/dL and you have symptoms.5
Your doctor may also check luteinizing hormone (LH), the hormone that tells your testicles to make testosterone. It shows whether the problem starts in your testicles or in the pituitary gland at the base of your brain. If your LH is low or normal, your doctor may also test prolactin. 5
Tell your doctor if you've been sick or sleeping poorly. Both can lower testosterone for a while, so your doctor may retest later.3 7
What Is a Dangerously Low Testosterone Level?
There's no official danger number. But if your level is below 150 ng/dL and your LH is low or normal, guidelines advise a brain scan (MRI). This rules out a problem with your pituitary gland.6
Low Testosterone Causes: Why It Happens
Testosterone drops by about 1% a year, starting in your late 30s. But age is rarely the only reason. Men low in testosterone often have one or more of these:
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Obesity or type 2 diabetes
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Sleep apnea (breathing stops and starts during sleep)
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Opioid pain medicines
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Past anabolic steroid use
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Heavy drinking
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Testicle injury, chemotherapy, or radiation
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Pituitary gland problems
What Causes Low Testosterone in Young Males?
In younger men, extra weight, poor sleep, steroids, and opioids top the list. In one study, just one week of five-hour nights cut young men's testosterone by 10 to 15%. 7 A 2026 review also suggests men's average levels have dropped sharply since the 1970s, though it isn't peer-reviewed yet.8
Low Testosterone Treatment: What Helps and What Doesn't
Step 1: Fix the everyday causes first
Losing weight is the strongest natural fix. In a review of 24 studies, men who lost about 10% of their weight raised their testosterone by about 84 ng/dL on average.9 Sleeping seven or more hours, strength training, cutting back on alcohol, and treating sleep apnea help too.
Step 2: Consider TRT if your levels stay low
If low levels and symptoms don't go away, your doctor may suggest testosterone replacement therapy (TRT). It comes as gels, shots, pellets, nasal gel, or pills.
Here's when most men start to notice changes:
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Sex drive: 3 to 6 weeks
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Mood: 3 to 6 weeks
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Muscle and body fat: 3 to 4 months
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Erections: up to 6 months
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Bones: 6 months or more 10
Note: TRT isn't an energy pill. In large trials, it didn't reliably fix tiredness .4
Is TRT safe?
In a large 2023 trial of 5,246 men, heart attacks and strokes were about as common on testosterone (7.0%) as on a placebo (7.3%). 11 That led the FDA to remove its heart-risk warning in 2025. 12 In June 2026, it went further, recognizing age-related low T as treatable and easing prostate warnings.13
Still, TRT can raise blood pressure and red blood cell count, and it slightly increased blood clots in the lungs. That's why regular checkups, including prostate screening, still matter.
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Planning to have kids? Read this first.
TRT tells your body to stop making its own sperm.5 If you are planning to have children, ask your doctor about more options before you start. |
Can Supplements Help Low Testosterone?
Most "T boosters" sold online have little proof behind them. But one nutrient is getting research attention: geranylgeraniol (GG), a natural compound that helped testicle cells make testosterone in lab studies. 14
In a small 2023 trial, the only gains showed up in men on the lower side of normal: about 7.5% after eight weeks. It's early research, so talk to your doctor before trying it.
Read More: GG for Testosterone
When to See a Doctor
If you're a male with low testosterone symptoms, don't guess. Book a visit if you notice:
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Sexual symptoms that last more than a few weeks
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Breast swelling or shrinking testicles
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Hot flashes
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Trouble getting your partner pregnant
Testosterone matters for women too. See our guide to normal testosterone and estrogen levels in women. To learn what causes high testosterone, read our complete guide to testosterone.
Frequently Asked Questions
Q1: Can low testosterone go back to normal?
Often, yes, if the cause is extra weight, poor sleep, or a medicine. Drops from aging are harder to reverse.
Q2: Does not ejaculating for 7 days increase testosterone?
No. This idea comes from a small 2003 study that was later retracted.
Q3: What is the best testosterone booster for men?
No booster has strong proof yet. GG shows early promise, as noted above, but ask your doctor before trying any supplement.
Q4: What are the symptoms of high testosterone in men?
High levels are rare unless you use steroids or take too much TRT. Signs can include acne, mood swings, and a high red blood cell count, which raises the risk of clots.
References
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Endocrine Society. (2007, September 6). Symptomatic testosterone deficiency relatively rare in men [Press release]. Newswise. https://www.newswise.com/articles/symptomatic-testosterone-deficiency-relatively-rare-in-men
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Wu, F. C. W., et al. (2010). Identification of late-onset hypogonadism in middle-aged and elderly men. New England Journal of Medicine, 363(2), 123–135. https://eprints.gla.ac.uk/43001/
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Cleveland Clinic. (2026, February 23). Low testosterone (male hypogonadism). https://my.clevelandclinic.org/health/diseases/15603-low-testosterone-male-hypogonadism
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Snyder, P. J., et al. (2016). Effects of testosterone treatment in older men. New England Journal of Medicine, 374(7), 611–624. https://pmc.ncbi.nlm.nih.gov/articles/PMC5209754
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American Urological Association. (2024). Evaluation and management of testosterone deficiency (2024). https://www.auanet.org/guidelines-and-quality/guidelines/testosterone-deficiency-guideline
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Mulhall, J. P., et al. (2018). Evaluation and management of testosterone deficiency: AUA guideline. The Journal of Urology, 200(2), 423–432. https://auau.auanet.org/sites/default/files/media/2023-09/Testosterone-Deficiency-JU.pdf
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UChicago Medicine. (2011, May 31). Sleep loss lowers testosterone in healthy young men. https://www.uchicagomedicine.org/forefront/health-and-wellness-articles/sleep-loss-lowers-testosterone
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Levy, A., et al. (2026). L26/O-204 Temporal trends in total and free testosterone (1972–2019): A systematic review and meta-trend analysis [Conference abstract]. Human Reproduction, 41(Suppl. 1), Article deag083.202. https://academic.oup.com/humrep/article/41/Supplement_1/deag083.202/8727608
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Corona, G., et al. (2013). Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: A systematic review and meta-analysis. European Journal of Endocrinology, 168(6), 829–843. https://pubmed.ncbi.nlm.nih.gov/23482592/
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Saad, F., et al. (2011). Onset of effects of testosterone treatment and time span until maximum effects are achieved. European Journal of Endocrinology, 165(5), 675–685. https://pmc.ncbi.nlm.nih.gov/articles/PMC3188848/
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Lincoff, A. M., et al. (2023). Cardiovascular safety of testosterone-replacement therapy. New England Journal of Medicine, 389(2), 107–117. https://www.nejm.org/doi/full/10.1056/NEJMoa2215025
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U.S. Food and Drug Administration. (2025, February 28). FDA issues class-wide labeling changes for testosterone products. https://fda.gov/drugs/drug-safety-and-availability/fda-issues-class-wide-labeling-changes-testosterone-products
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American Urological Association. (2026). HHS announces updates to testosterone replacement therapy labeling. https://www.auanet.org/advocacy/get-involved/comment-letters-and-resources/hhs-announces-updates-to-testosterone-replacement-therapy-labeling
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Gheith, R., et al. (2023). The effects of geranylgeraniol on blood safety and sex hormone profiles in healthy adults: A dose-escalation, randomized, placebo-controlled trial. Nutraceuticals, 3(4), 605–618. https://www.mdpi.com/1661-3821/3/4/43
Disclaimer: This article is for informational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider regarding any medical concerns or conditions.
