Low levels of testosterone, often shortened to ‘low T’, affects millions of men worldwide. Although testosterone naturally decreases as men age, there’s a certain lower limit. If your testosterone levels drop below this limit, it is a cause for concern.

Low T refers to testosterone levels that are below 300 nanograms per deciliter (ng/dL) of blood. It affects between 20-40% of older men but it can affect people of any age.

Diagnosis of low T is determined through blood testing. After such diagnosis, physicians may offer testosterone replacement therapy (TRT) or testosterone supplements to try and gradually increase testosterone levels to within the normal range.

The Most Common Causes of Low Testosterone:

Symptoms of low testosterone include low energy and mood, low libido or erectile dysfunction, and loss of muscle mass. If you are experiencing these symptoms, it might be worth going to see a healthcare professional to get a blood test.

If you have low testosterone levels for a while, you may also experience more long-term symptoms of low T, such as increased body fat, breast development, osteoporosis (thinning of the bones), or infertility.

There are many potential causes of low T. It’s important to identify the specific cause of your reduced testosterone levels so that you can get the right form of treatment.

So, what are some of the most common causes of low testosterone:

Genetic conditions that are present at birth, such as Klinefelter syndrome.

Abnormal development of the genitalia.

Injury or trauma to the testicles due to an accident or surgery.

Cancer treatments, such as chemotherapy or radiotherapy.

Under activity of the pituitary gland, leading to hormone deficiency.

Autoimmune conditions.

Obesity or metabolic syndrome.

Alcohol abuse or cirrhosis of the liver.

Excessive estrogen.

Chronic kidney failure (CKD).

Medications, including anti-depressants and strong pain killers.

HIV or AIDS.

Aging.

The above causes of low testosterone can be split into two categories – primary hypogonadism and secondary hypogonadism.

In primary hypogonadism, the testes are underactive. This means that they are not producing as much testosterone as they should be.

Primary hypogonadism occurs due to inherited conditions or underdeveloped gentians. It can also be caused by physical injury, trauma, or cancer treatments.

Unlike primary hypogonadism, secondary hypogonadism acts indirectly. It occurs due to damage to the pituitary gland or hypothalamus. As a result of this damage, these parts of the brain no longer produce enough (or any) sex hormones that usually stimulate the testicles to produce testosterone.

This pituitary damage can be inherited at birth (pituitary disorders). They can also be caused by tumors or inflammatory conditions affecting these areas of the brain.

Taking strong opioid medications or having a high body fat percentage may also be the cause of secondary hypogonadism and low testosterone.

Primary and secondary hypogonadism are not mutually exclusive. You can have one or the other, or you can have a mixture of those. Having a mixture is more common as you get older.