Signs Of Low Testosterone In Men And When To Get Tested

The most common signs of low testosterone in men are reduced sex drive, erectile trouble, ongoing fatigue, low mood, poor focus, lost muscle, and added body fat. No single symptom proves anything alone, and most overlap with stress, poor sleep, and other conditions. A real diagnosis needs two things together: a low morning blood level and symptoms that fit (Bhasin et al., 2018). If several signs have stacked up with no clear cause, testing is the next step. Marek Health is a telehealth provider that evaluates men for hormone concerns and explains how testosterone levels are measured.

What is testosterone and what does it do?

Testosterone is the main male sex hormone, made mostly in the testicles. It supports sperm production, muscle and bone, red blood cells, sex drive, and mood and concentration. Testosterone tends to decline gradually with age, though the rate varies widely and some men decline very little.

When testosterone drops below what the body needs and symptoms appear, that is testosterone deficiency, or male hypogonadism. It can start in the testicles (primary) or in the brain signals that drive them (secondary), which is why testing checks more than one marker (Mulhall et al., 2018).

Risk factors for low testosterone

Some men are more likely to develop low testosterone, and the odds climb with age and certain conditions. Low testosterone becomes more common with age and is seen more often in men with obesity or type 2 diabetes (Mulhall et al., 2018). Common contributors include obesity, type 2 diabetes, kidney or liver disease, heavy alcohol use, opioids and corticosteroids, poor sleep, and stress.

What are the common signs of low testosterone?

The signs of low testosterone cluster in three areas: sexual function, body composition, and energy or mood. They creep in slowly, so men often write them off as aging or stress.

Sexual signs

Reduced sex drive may prompt evaluation, but it has many possible causes besides hormones. Low testosterone can also affect erections and contribute to sexual health changes, though it is rarely the whole story. Erectile difficulty can also signal vascular or other conditions worth evaluating.

Body signs

Because testosterone helps hold muscle and bone, low levels can show as muscle slipping despite training, extra belly fat, and thinner bones. Some men notice breast tissue changes (gynecomastia) when the testosterone-to-estrogen balance shifts. Lower bone density may increase fracture risk over time.

Energy, mood, and focus

Constant fatigue, low drive, a flat mood, and trouble with focus and memory some men call brain fog can travel with low testosterone. These signs are the least specific, since poor sleep, stress, and depression look the same, so evaluation by a provider comes first.

Why low testosterone is worth taking seriously

Untreated low testosterone is more than low libido and energy. A lasting, symptomatic deficiency is a medical condition, not a phase. It can affect bone strength and body composition, and it often occurs alongside obesity and diabetes, conditions that can influence one another (Mulhall et al., 2018). Not every dip needs treatment, but the pattern is worth checking.

How is low testosterone diagnosed?

Low testosterone is confirmed with a blood test plus symptoms, not a quiz alone. Testosterone peaks in the morning, so blood is drawn early, and a low result is repeated on a second day (Bhasin et al., 2018). A clinician interprets blood testing together with symptoms against accepted clinical criteria, since no single number defines low testosterone for everyone (Mulhall et al., 2018). Providers may order other blood tests to clarify the cause and what is appropriate for each person. A quiz flags symptoms but cannot measure a hormone, so a provider orders the labs and reads them in context, which is how a telehealth evaluation works.

Treatment options for diagnosed low testosterone

When evaluation points to a deficiency, treatment is testosterone replacement therapy, and whether to start is a decision you make together with your provider, weighing the benefits and risks for you. Approved products come as injections (cypionate or enanthate), transdermal gels and patches, a buccal system, and pellets, cleared for low levels tied to a medical condition, not aging alone, a limit the FDA kept in its February 2025 labeling update (FDA, 2025). Compounded testosterone is not FDA-approved and should not be assumed equivalent to approved products.

Treatment carries risk, so monitoring follows. In a large trial of men at high cardiovascular risk, testosterone did not increase the main measure of major cardiac events compared with placebo, though it was associated with more atrial fibrillation and pulmonary embolism, or blood clots in the lungs (Lincoff et al., 2023). Those findings apply to that higher-risk group, and individual risk should be assessed by a provider. On those findings the FDA dropped the cardiovascular boxed warning in 2025 and added a blood-pressure warning (FDA, 2025), so heart health stays on the list. Testosterone can raise red blood cell levels, so providers monitor blood counts and adjust treatment when needed (Bhasin et al., 2018). Therapy can lower sperm production and affect future fertility; that effect varies and is not guaranteed to reverse, so ask your provider about fertility-preserving options before starting.

Lifestyle and hormone health

Everyday habits matter too. Healthy sleep, regular activity, weight management, and limiting alcohol support hormone health, though their effect on testosterone varies and does not replace evaluation when deficiency is suspected. Steady rest supports sleep and hormones, and managing body fat may help, but none of this fixes a true deficiency on its own.

When should you see a provider about low testosterone?

See a provider when several signs have lasted for weeks without an obvious cause like poor sleep or stress. There is no reason to self-diagnose from a checklist. A clinician can order the right labs, confirm whether the level is low, and weigh treatment. Access to prescription testosterone, a controlled medication, runs through that evaluation and only where state law allows. If these signs of low testosterone feel familiar, the next step is a blood test, which you can begin by getting started with a provider.

Disclaimer: This blog post is intended for informational purposes only and should not be considered medical advice. Always consult a healthcare professional before making changes to your health routine.

FAQs

What are the most common signs of low testosterone? 

The most common signs of low testosterone are low sex drive, erectile trouble, fatigue, low mood, poor focus, muscle loss, and added body fat. No single sign confirms it. Diagnosis needs symptoms plus a low morning blood level on two separate days (Bhasin et al., 2018).

At what level is testosterone considered low? 

There isn't one fixed number that applies to everyone. A provider determines whether testosterone is low using established clinical criteria and morning blood testing, weighed together with symptoms (Mulhall et al., 2018).

Can low testosterone be diagnosed from symptoms or an online quiz? 

No. Symptoms and online quizzes overlap with sleep loss, stress, thyroid issues, and depression. A blood test plus a clinical evaluation is required, since a quiz cannot measure a hormone (Bhasin et al., 2018).

Are the signs of low testosterone reversible with treatment? 

When a deficiency is confirmed, testosterone replacement therapy can improve symptoms in men whose low levels tie to a medical condition. Results vary by person, and the FDA notes approved testosterone is not for low levels from aging alone (FDA, 2025).

Does testosterone therapy increase heart risk? 

In a large trial of men at higher cardiovascular risk, testosterone did not raise the main measure of major cardiac events compared with placebo, though it was associated with more atrial fibrillation and pulmonary embolism, a type of blood clot in the lungs (Lincoff et al., 2023). These results may not apply to everyone, and the FDA updated labeling in 2025 to add a blood-pressure warning.

Can low testosterone affect fertility, and does treatment make it worse? 

Low testosterone can reduce sperm production, and testosterone therapy can lower it further. That effect varies between men and is not guaranteed to reverse, so anyone planning children should ask about fertility-preserving options before starting (Mulhall et al., 2018).

When should I see a provider about low testosterone? 

See a provider when several signs have lasted for weeks without a clear cause like poor sleep or stress. A licensed clinician can order morning labs, confirm whether the level is low, and discuss whether treatment fits. Prescription testosterone is a controlled medication and requires evaluation.

References

• J Clin Endocrinol Metab. 2018;103(5):1715-1744

• J Urol. 2018;200(2):423-432

• N Engl J Med. 2023;389(2):107-117

• U.S. Food and Drug Administration. Drug Safety and Availability. February 28, 2025