Information for patients

What is low testosterone?

Testosterone is an essential male hormone produced in the testes that plays a crucial role in the health and well being of our bodies. Testosterone is responsible for typical male sexual characteristics and is required by all men for a healthy life physically and psychologically.
Figure 1: Actions of Testosterone in an adult male
vergrößern Figure 1: Actions of Testosterone in an adult male
Low testosterone (the medical term is hypogonadism) simply means having a very low testosterone level. It happens when the testes do not function normally or when internal hormone production is out of balance. Low testosterone can occur in men of any age. However, there is a progressive decline in testosterone levels as men age.

Although not a common condition, it is hard to say exactly how many men have low testosterone. Doctors believe that 5 in 1,000 men are living with some form of hypogonadism. The number of men with low testosterone increases with age and as many as 1 in 5 European men over the age of 50 has moderate or severe symptoms of testosterone deficiency.

What causes low testosterone?

There are two main types of low testosterone condition, and each has its own cause: these are referred to as primary and secondary hypogonadism.

In primary hypogonadism, low testosterone is caused by a problem with the testes. Secondary hypogonadism occurs when the complex hormonal system responsible for producing male sex hormones goes out of balance or breaks down.

Late-onset hypogonadism refers to low testosterone associated with advancing age. Men normally experience some decline in testosterone levels as they age due to reduced function of the testes and the complex hormonal system. This decline may be accelerated by poor health, and some men’s testosterone levels may fall too far.

About 20% of men older than 60 years and 30–40% of men older than 80 years have testosterone levels below the physiological range for younger men.

Age related decline in testicular function

Regardless of the underlying cause of low testosterone, the treatment approach – returning testosterone to normal levels – will be the same, and you can expect to see the same improvements in symptoms.

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Last updated: 2019