Testosterone is a hormone present in both genders.(It primarily plays a key in development of male organs and secondarily in deepening of voice.)For both genders it is responsible for muscle hypertrophy( dolay/buff muscles)
If goin to gym doesnt help you know your hormone is low.

The hormone is responsible for sex drive as well if the levels get dangerously low due to poor life style or style it can even lead to infertility. Now i dont suggest you go on steroids for muscle hypertrophy or sex drive. But working on life style and mental health is important.

Poor life style or stress*