Final answer:
Low testosterone levels can cause fatigue and low sex drive in men.
Step-by-step explanation:
A common cause of fatigue and low sex drive in men is low testosterone levels. Testosterone is a hormone responsible for regulating sex drive and energy levels in men. When testosterone levels are low, it can lead to symptoms such as fatigue, decreased libido, and reduced energy levels.
Learn more about causes of fatigue and low sex drive in men