Ashwagandha is a natural herb that has lately gained a solid reputation for boosting testosterone. Many studies around the world have shown that supplementation of ashwagandha in the mean has led to a significant increase in testosterone levels, improved sperm quality, and higher antioxidant levels. Another study has shown that men who are overweight and aged 40-70 who have mild fatigue noticed an increase in testosterone levels significantly after taking an ashwagandha supplement for 8 weeks.