A bus driver in his early forties came to the counter with a handwritten list in his pocket. His energy had dropped, his interest in sex had faded, and he was waking tired even after a full night's sleep. "The receptionist at the clinic said to come back with a list," he said, half amused. "So here it is. Is it my testosterone?" This scene is a composite of several conversations, and the list he brought is a good place to start.

Low testosterone symptoms are common in men over 40, but they are also very ordinary. Tiredness, low mood, poor sleep and reduced desire have many causes. A checklist can help you describe what is happening, but it cannot diagnose low testosterone on its own. The diagnosis needs two things: symptoms, and blood tests taken properly in the early morning.

The symptoms doctors ask about

The Mayo Clinic lists these symptoms of low testosterone: lowered sexual desire and activity, erectile dysfunction or fewer erections, breast tenderness or swelling, infertility, height loss, low-trauma fractures or low bone density, and hot flashes or sweats. It also includes less energy, motivation and confidence, feeling depressed or having trouble focusing, sleepiness and sleep problems, mild unexplained anemia, lower muscle mass and strength, and more body fat.

The andropause symptom checker on the South Tees Hospitals NHS Foundation Trust website covers similar ground, including joint pain and muscle ache, excessive sweating, irritability, fewer morning erections, and a feeling that you have passed your peak sexually. The page itself says the questionnaire score on its own cannot tell you whether you have testosterone deficiency.

Note your symptoms as a list, with how long they have been going on and how much they affect your work, sleep and relationships. Bring it to your appointment rather than trying to decide on your own.

Preparing for your appointment

Bring three things: your symptom list, a full list of your medicines and supplements, and your health history, including any family history of prostate cancer, heart disease or diabetes. Note the time of day your symptoms are worst, and whether your sleep has changed. Ask whether your blood test can be booked for early morning, because the timing matters for the result. If you have had a PSA test before, bring the result. It also helps to ask what the next step is if the first test is low, so there are no surprises.

Why symptoms are not enough

The Mayo Clinic states that the signs and symptoms of low testosterone are not specific to low testosterone. Age, medicines and other conditions can cause them too. It notes that a body mass index of 30 or higher can produce similar symptoms. Low mood and poor sleep, both on the symptom lists above, can overlap with the problem as well. That is why a doctor will look at the whole picture before deciding what the symptoms mean.

How the blood test is done

The American Urological Association (AUA) guideline, approved in 2018 and reviewed with its validity confirmed in 2024, is widely used by US clinicians. It states that a total testosterone level below 300 ng/dL is a reasonable cut-off. It also says the diagnosis should be made only after two total testosterone measurements, on separate occasions, both taken in the early morning. If the first result is low and the second is normal, the guideline leaves it to the clinician's judgment whether to use a third test.

The Endocrine Society guideline (2018) takes a similar line. It asks for symptoms and signs of testosterone deficiency, together with unequivocally and consistently low testosterone levels. It recommends confirming the diagnosis with a repeat morning fasting measurement. The Mayo Clinic adds that if the first test is low, the test is repeated to confirm it.

Practically, that means a single afternoon result is not enough, and neither is a home kit you cannot repeat in the morning. Ask your doctor when the sample should be taken and whether a repeat is needed.

What the number means

A total testosterone result is a snapshot. It can vary with the time of day, with illness, and between laboratories. That is why the guidelines ask for two morning samples, and for the result to be read alongside your symptoms. A number just under 300 ng/dL is not automatically a diagnosis, and a number just above it does not rule out a problem if your symptoms are clear. Your clinician looks at the whole picture, and that is the right way to decide.

When testing may be considered without symptoms

The AUA guideline says testing can be considered even without symptoms in some situations, such as unexplained anemia, loss of bone density, diabetes, HIV/AIDS, male infertility, pituitary problems, past chemotherapy or testicular radiation, and long-term use of opioid painkillers or corticosteroids. Outside those situations, the usual path is symptoms first, then a proper test.

What a checklist cannot do

The AUA guideline does not recommend using questionnaires to define who is a candidate for therapy, or to monitor how well treatment is working. A checklist is a tool for talking to your clinician, not a diagnosis. Keep your list, but let the blood tests and the full assessment decide.

Before any treatment: PSA and prostate health

If testosterone treatment is ever discussed, the AUA guideline says PSA should be measured in men over 40 before therapy starts. The NHS PSA page explains that a PSA test checks prostate-specific antigen in the blood, and that an enlarged prostate or a urine infection can change the result. It also advises avoiding ejaculation, strenuous exercise and cycling for 48 hours before the test.

The Endocrine Society guideline recommends against testosterone therapy in men with breast or prostate cancer, and against starting it without further urology assessment in men with a PSA above 4 ng/mL, or above 3 ng/mL in men at high risk of prostate cancer. The AUA guideline tells clinicians to inform patients that there is no evidence linking testosterone therapy to the development of prostate cancer. A high PSA does not mean cancer, and a normal one does not rule it out, so the decision is made with your doctor, not from a number alone.

Treatment risks you should know

Testosterone therapy has benefits for some men, and it has real risks. The AUA guideline (2018) tells clinicians to explain that low testosterone is itself a risk factor for heart disease. Since then, the TRAVERSE trial (2023) followed 5,246 men aged 45 to 80 with low testosterone and existing heart disease or a high risk of it. Major heart events (heart attack, stroke or death from heart disease) happened at a similar rate with testosterone gel and placebo, 7.0% and 7.3%. The testosterone group did have more atrial fibrillation (an irregular heart rhythm), acute kidney injury and blood clots in the lungs. After that trial, the FDA announced in 2025 that it was removing the boxed warning language about a higher risk of heart problems from testosterone product labels, while adding a warning about raised blood pressure. The Mayo Clinic notes that therapy has been linked to blood clots in the veins. Clinicians may advise against it if you want to father children soon, or if you have a history of breast or prostate cancer, untreated severe sleep apnea, uncontrolled heart failure, leg or lung clots, or a recent heart attack or stroke.

Treatment is never a substitute for finding out what is causing the symptoms. Sleep, weight, mood, alcohol and medicines all influence energy and sexual health, and your doctor can help you look at them together.

Questions to ask your doctor or pharmacist

Do my symptoms fit low testosterone, or could another cause explain them better?
When and how should my blood test be taken, and do you need two morning samples?
Should I have a PSA test before any treatment, and what would my result mean?
Are there health conditions, such as sleep apnea, diabetes or heart disease, that you want to check first?
What are the risks of treatment for me in particular, including clots and heart health?
Which other medicines or supplements might be affecting my energy or libido?

Frequently asked questions

Is low testosterone just part of getting older?

Testosterone levels do tend to fall with age, but falling is not the same as causing symptoms. The question is whether your level is low and whether your symptoms come from it, which a doctor can assess with proper tests.

Can I check my testosterone at home?

Home kits cannot replace the early-morning, repeated blood tests that guidelines describe. If you are considering one, ask your doctor first, so the result can be read properly.

Should I take a testosterone booster?

Supplements sold as testosterone boosters are not a substitute for a diagnosis, and some can interact with medicines. Speak to your pharmacist before taking any product, and tell your doctor what you are using.

Will my symptoms go away on their own?

Some symptoms, such as tiredness linked to poor sleep or stress, may improve when the cause is treated. Persistent symptoms deserve a proper assessment rather than waiting.

If you'd like the full guide, my book Low Testosterone and Energy After 40 goes deeper into symptoms, testing, testosterone replacement and the everyday steps that can help with energy.

Sources

Mayo Clinic. Male menopause: myth or reality?
Endocrine Society. Testosterone therapy in men with hypogonadism: clinical practice guideline
American Urological Association. Evaluation and Management of Testosterone Deficiency guideline (PDF).pdf)
South Tees NHS Foundation Trust. Low testosterone (testosterone deficiency syndrome) information
NHS. PSA testing
NHS. Heart attack
Lincoff AM, et al. Cardiovascular safety of testosterone-replacement therapy (TRAVERSE). New England Journal of Medicine. 2023;389(2):107-117.
U.S. Food and Drug Administration. FDA issues class-wide labeling changes for testosterone products (February 28, 2025)