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 level 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.
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.