Testosterone levels can be measured through a simple blood test performed by your doctor. The testosterone levels should be between 280 and 1,100 nanograms per deciliter (ng/dL) for a healthy adult male. In adult females, the levels are between 15 and 70 ng/dL.
A testosterone level of below 300 ng/dL in an adult male is considered to be low. This tends to be due to issues with your pituitary gland. This is found at the base of your brain and is responsible for sending signals to the testes to produce more testosterone.
The condition where your testosterone production is reduced is referred to as hypogonadism.