Testosterone is a hormone that plays a role in various bodily functions. It contributes to male development and reproductive health, including muscle growth, bone density, and sex drive. Maintaining appropriate testosterone levels is beneficial for overall health. This article explores what defines low testosterone numbers, its signs, influencing factors, and diagnostic methods.
Understanding Testosterone Levels
Testosterone circulates in the blood in different forms, primarily as total testosterone and free testosterone. Total testosterone measures the entire amount of the hormone in the bloodstream, encompassing both bound and unbound forms. Most testosterone is bound to proteins like sex hormone-binding globulin (SHBG) and albumin. Free testosterone is the unbound form, making up a small percentage, and is considered the active form that can readily affect body cells.
For adult males, a normal total testosterone level typically ranges from 300 to 1000 nanograms per deciliter (ng/dL). Levels below 300 ng/dL are generally considered low and may indicate a deficiency. Free testosterone levels are often measured in picograms per milliliter (pg/mL), with a normal range for adult males typically between 50-250 pg/mL. Even if total testosterone is within the normal range, low free testosterone can still lead to symptoms due to less active hormone being available.
Signs and Symptoms of Low Testosterone
Low testosterone levels can manifest through various physical, emotional, and sexual changes. One common indicator is a decreased sex drive, often accompanied by erectile dysfunction. Individuals may also experience persistent fatigue and reduced energy levels.
Physical alterations can include a decrease in lean muscle mass and strength, alongside an increase in body fat. Mood changes such as irritability or symptoms resembling depression can also occur. Additional signs might involve decreased bone density, sleep disturbances, and a reduction in body and facial hair. These symptoms are not exclusive to low testosterone and can point to other health conditions.
Factors Influencing Testosterone Levels
Several factors can influence an individual’s testosterone levels, leading to a decline. Advancing age is a common contributor, as testosterone levels naturally decrease with time, typically beginning around a man’s 30s. Obesity is linked to lower testosterone, partly because excess fat cells can increase estrogen levels, which may then reduce testosterone production.
Chronic medical conditions frequently play a role in testosterone reduction. These include type 2 diabetes, kidney disease, and liver disease. Certain medications, such as opioids and corticosteroids, can negatively impact testosterone production. Disorders of the pituitary gland, which regulates hormone production, or direct injury and infection to the testicles, can lead to decreased testosterone levels.
How Low Testosterone is Diagnosed
Diagnosing low testosterone typically begins with a review of symptoms and a physical examination by a healthcare provider. If symptoms suggest a deficiency, blood tests are then ordered to measure testosterone levels. These blood tests are usually performed in the morning because testosterone levels are generally at their highest during these hours.
To confirm a diagnosis, multiple blood tests are often necessary due to the natural daily variations in hormone levels. Both total testosterone and free testosterone levels may be measured to provide a comprehensive picture. The results, combined with a patient’s symptoms and overall health history, guide the healthcare provider in determining whether a low testosterone diagnosis is appropriate.