I have Low Testosterone.
Testosterone is produced by the Leydig cells in the testes. There are two forms of hypogonadism;
The source of the problem is in your testicles. The Leydig cells are receiving the impulses from your brain to produce testosterone, but they are not doing so.
Reasons for this form of hypogonadism normally relate to health conditions rather than lifestyle. Genetic and autoimmune disorders and infections are the likely culprits.
The source of the problem is not in your testes. Your testes are normal, but they are not receiving the messages sent from your brain which tell them to produce testosterone.
Whilst genetic disorders, diseases and infections can be the culprit here too, lifestyle choices are normally more of a causative factor. Obesity, nutrition or drug use/misuse can interfere with the ability of the brain to communicate with the testes.