Low Testosterone in Men: Symptoms, Causes, Testing and Treatment

Low testosterone is more than simply having a low number on a blood test. Testosterone deficiency is diagnosed when a man has symptoms or signs that fit testosterone deficiency together with consistently low testosterone levels on appropriate testing. Symptoms can include reduced sex drive, erection problems, fewer morning erections, low energy, reduced muscle mass, infertility and changes in mood. Because many of these symptoms can also have other causes, testing and medical evaluation are important before starting treatment.

Testosterone is a hormone produced mainly by the testes under the control of the brain and pituitary gland. It has an important role in sexual function, sperm production, muscle and bone health, red blood cell production and other aspects of male health.

Low testosterone, also called testosterone deficiency or hypogonadism, means the body is not producing enough testosterone for its needs. A low laboratory result by itself does not automatically mean that a man has testosterone deficiency. The result needs to be interpreted alongside symptoms, the timing of the blood test, the laboratory reference range and the underlying cause.

Symptoms can vary considerably from one man to another. Sexual symptoms are often more specific than general symptoms such as tiredness or low mood.

Common symptoms and signs of low testosterone may include:

Low testosterone can contribute to sexual problems, including reduced sexual desire and fewer spontaneous erections. However, erectile dysfunction has many possible causes and does not automatically mean that testosterone is low.

Diabetes, high blood pressure, vascular disease, obesity, medications, psychological factors, nerve problems and other health conditions can also contribute to erectile dysfunction. Men with erectile dysfunction may therefore need an evaluation rather than assuming that testosterone is the cause.

Low testosterone can result from a problem in the testes themselves or from reduced hormonal signalling between the brain, pituitary gland and testes.

Common causes and contributing factors include:

Testosterone levels tend to decline gradually with age, but symptoms should not automatically be attributed to normal ageing. Tiredness, reduced libido, erectile difficulties, weight gain and low mood can have many causes.

A man with persistent symptoms should be evaluated rather than assuming that ageing alone explains the problem. Current endocrine guidance also emphasizes that symptoms alone are not enough to diagnose testosterone deficiency.

Testosterone levels change during the day and are generally higher in the morning. For this reason, an early-morning blood test is used when evaluating possible testosterone deficiency.

The American Urological Association recommends two separate early-morning total testosterone measurements before making a diagnosis. A total testosterone level below 300 ng/dL is commonly used as a reasonable diagnostic cutoff, but the diagnosis still depends on the clinical picture and laboratory interpretation.

If the testosterone level is low, additional tests may be needed to understand why it is low.

There is no single testosterone number that should be interpreted in isolation for every man. Laboratories use their own reference ranges, and testosterone assays can differ.

The AUA uses a total testosterone level below 300 ng/dL as a reasonable cutoff, while also requiring appropriate clinical evaluation and repeated morning testing. The Endocrine Society recommends diagnosing hypogonadism only when symptoms or signs consistent with testosterone deficiency are accompanied by unequivocally and consistently low testosterone concentrations.

Treatment depends on the cause, severity of symptoms, testosterone results, age, general health and fertility plans. The first step is to establish whether true testosterone deficiency is present and why it is occurring.

If a reversible contributor such as obesity, a medication effect or another medical condition is identified, addressing that problem may be an important part of treatment.

For men with confirmed testosterone deficiency, testosterone replacement therapy may be considered when appropriate. Available forms can include injections, gels and other prescription formulations. The choice depends on the clinical situation, treatment goals, fertility plans, cost, preference and potential side effects.

This is an important issue for men who are trying to have children. Testosterone replacement therapy can suppress the body's own hormonal signals to the testes and can reduce sperm production.

For this reason, men who are planning fertility in the near term should discuss their plans with a urologist before starting testosterone treatment. Treatment aimed at improving testosterone symptoms is not automatically the same as treatment aimed at improving fertility.

Testosterone therapy can be effective for appropriately diagnosed testosterone deficiency, but it is not a treatment that should be started simply because a blood test shows a low number.

The benefits and risks need to be discussed before treatment. Depending on the patient, monitoring may include testosterone levels, blood counts and assessment of prostate-related risk. Some men should not start testosterone therapy because of specific medical conditions or fertility plans.

Consider a urology evaluation if you have persistent low libido, erectile problems, fewer morning erections, unexplained fatigue together with sexual symptoms, reduced testicular size, infertility or a previous low testosterone result.

A urologist can review symptoms, medications, medical history, examination findings and hormone reports to determine whether testosterone deficiency is actually present and whether another condition may be responsible.

Low testosterone is increasingly discussed online, but self-treatment can create problems. Testosterone boosters, anabolic steroids and prescription testosterone should not be used without proper medical assessment.

A supplement cannot confirm why testosterone is low, and taking testosterone without considering fertility can reduce sperm production. The safer approach is to confirm the diagnosis and identify the cause before choosing treatment.

Low testosterone in men can cause reduced libido, erection problems, fewer morning erections, low energy, reduced muscle mass and fertility problems. However, these symptoms can also have other causes.

The diagnosis should be based on appropriate symptoms together with consistently low testosterone confirmed through properly timed blood tests. Once the cause is understood, treatment can be planned around the man's symptoms, health, fertility goals and long-term needs.