The main male sex hormone that influences libido, erections, muscle mass, bone density, and mood. It also helps regulate blood sugar, cholesterol, and inflammation.
Testosterone levels decline with age, usually starting around 30 years old. This can lead to symptoms such as low sex drive, erectile dysfunction, fatigue, depression, weight gain, and loss of muscle and bone mass.
Testosterone levels can also be affected by lifestyle factors such as stress, diet, exercise, sleep, alcohol consumption, and smoking.