There are two types of low testosterone in men.  One is called “Primary Hypogonadism” and the other type is “Secondary Hypogonadism“.

Primary hypogonadism is when the testes do not produce adequate amounts of testosterone. The causes of primary hypogonadism can range from congenital conditions like Klinefelter’s syndrome to testicle injuries, use of anabolic steroids, and some types of tumors

Secondary hypogonadism describes low testosterone that occurs as a result of conditions or issues with the pituitary glands. Secondary hypogonadism can also come from congenital conditions or be acquired later in life. Some of the most common acquired causes include kidney failure, chronic alcohol abuse, cirrhosis of the liver, unchecked diabetes and even obesity. In fact, many experts believe that there is a strong connection between obesity and low testosterone.

The type of low testosterone that is often tied to the natural aging process is known as late-onset hypogonadism (LOH). Late-onset hypogonadism is also more likely to occur in aging men who are overweight.