Low Testosterone Symptoms After 40: What Is Normal Aging and What Is Worth Testing?
If you are tired, flat and a little softer around the middle than you used to be, "low testosterone" is an easy answer to reach for. Sometimes it is the right one. Often it is not. I'm not a doctor, and this is not medical advice. Here is what the research says about which symptoms matter, and how doctors actually decide.
What are the symptoms of low testosterone?
The list you will see online is long: low energy, lower sex drive, fewer morning erections, low mood, less muscle and strength, more body fat, trouble concentrating. The problem is that most of these are common in men with perfectly normal testosterone. They are also what poor sleep, stress, extra weight and some medications can look like.
Which symptoms actually point to low testosterone?
The best evidence I know of comes from the European Male Ageing Study, which surveyed 3,369 men aged 40 to 79 in eight European centers. The researchers started from 32 candidate symptoms and checked which ones actually went along with low testosterone (Wu et al., NEJM, 2010).
- Three sexual symptoms were the ones that consistently clustered with low testosterone: erectile dysfunction, fewer sexual thoughts and fewer morning erections.
- Psychological symptoms, such as low mood or fatigue, had little or no association with testosterone level.
- The study defined late-onset hypogonadism as at least three of those sexual symptoms plus a low testosterone level. Only about 2.1% of the men met that definition (63 of 2,966).
That second bar is the key point. Even the symptoms that fit best are common in men whose testosterone is fine. A symptom alone can't tell you your level.
Is some decline in testosterone just normal aging?
Yes. In the Massachusetts Male Aging Study, which followed men for several years, total testosterone drifted down by roughly 1% to 2% a year on average, with large differences from one man to the next (Feldman et al., 2002). A slow drift is not the same as a deficiency. Most men never cross the line where a doctor would call their level low.
What else can look like low testosterone?
- Poor sleep. In a small lab study, ten healthy young men were limited to five hours in bed a night for eight nights, and their testosterone dropped roughly 10 to 15 percent (Leproult and Van Cauter, 2011). More in how sleep affects testosterone.
- Extra body fat, stress and low mood. All of them cause tiredness and low drive on their own.
- Medications and other health conditions. Many have fatigue or low libido as a side effect. Tell your doctor everything you take.
This is why guidelines insist on a blood test before anyone is told their problem is hormonal.
How is low testosterone diagnosed?
| Guideline | What it asks for |
|---|---|
| American Urological Association (2018) | Symptoms, plus total testosterone consistently below 300 ng/dL on at least two early-morning tests taken on separate days. |
| Endocrine Society (2018) | Symptoms and signs consistent with deficiency, plus unequivocally and consistently low levels, confirmed by repeating a morning fasting total testosterone test. |
| European Male Ageing Study (2010) | At least three sexual symptoms, plus total testosterone below 8 nmol/L (about 231 ng/dL), or below 11 nmol/L (about 317 ng/dL) with low free testosterone. |
The numbers differ between groups, and that is normal. What they share is the same idea: symptoms first, then repeated morning blood tests, then a doctor's judgment. For the full normal range and how it was defined, see my guide to testosterone boosters.
When should I see a doctor?
- If tiredness, low drive or the sexual symptoms above last for weeks and don't improve with better sleep and routine.
- If you notice sudden or unexplained changes, or other symptoms that worry you.
- Before starting any supplement, especially if you take prescription medication.
Ask for a morning blood test, and mention the symptoms and medications. I explain how to get tested and read the results in a separate guide. A supplement is not a test and not a treatment. If the first result is low, the next step is a repeat test and a conversation with your doctor.
Frequently asked questions
What are the first signs of low testosterone?
There is no single early sign. In the European Male Ageing Study, the symptoms most consistently linked to low levels were erectile dysfunction, fewer sexual thoughts and fewer morning erections. Fatigue and low mood had little association with testosterone level. Only a blood test can confirm it.
What testosterone level is considered low?
The American Urological Association uses total testosterone consistently below 300 ng/dL on two early-morning tests, together with symptoms. The European study used different cutoffs: about 231 ng/dL, or about 317 ng/dL when free testosterone was also low. Groups and labs differ, so your doctor interprets the result.
Does testosterone drop with age?
On average, total testosterone declines by about 1% to 2% a year in middle-aged men, but the change varies widely between individuals. A gradual decline is not automatically a deficiency.
Can poor sleep lower testosterone?
In a small lab study, eight nights limited to five hours in bed lowered testosterone by roughly 10 to 15 percent in ten healthy young men. It was a small study, but it shows how sensitive the number is to sleep.
Should I take a testosterone booster for these symptoms?
Not before getting tested. Many symptoms have other causes, and most boosters have little good evidence behind them. See my guide to what the research says on testosterone boosters.
Sources
- Wu FCW, et al. Identification of late-onset hypogonadism in middle-aged and elderly men. N Engl J Med. 2010;363:123-135. doi:10.1056/NEJMoa0911101
- Review of the European Male Ageing Study findings: Diagnosis and treatment of hypogonadism in older men: proceed with caution. PMC3739065 (source for the figure of men with normal testosterone who still had the symptoms)
- Feldman HA, et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts Male Aging Study. J Clin Endocrinol Metab. 2002;87(2):589-598. doi:10.1210/jcem.87.2.8201
- Mulhall JP, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. J Urol. 2018. doi:10.1016/j.juro.2018.03.115
- Bhasin S, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018. PubMed 29562364
- Leproult R, Van Cauter E. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA. 2011;305(21):2173-2174. JAMA Network
Marcus Hale
Writer at The Male Ledger. Not a doctor.
I write about testosterone, energy and vitality after 40, and I link to the studies so you can check my work. Marcus Hale is a pen name; here is why.