• Obesity

• Aging

• Medications: More than one in four adults in the US take statins, which can decrease the circulating testosterone and lower the body's ability to respond to it as they bind to testosterone and other androgens.

• Genetics

• Sedentary lifestyle and lack of exercise

• Poor diet

• Stress

• Lack of sleep

• Environmental factors

• History of performance-enhancing drug (PED) use

• Chronic diseases, chemotherapy, traumatic head injuries, and other medical conditions