G10 force Another herb that is clinically proven to increase testosterone in both men and women is Eurycoma longifolia, commonly known as Tongkat Ali or Longjack. British Journal of Sports Medicine reported that in a double-blind placebo controlled trial, the use of Tongkat Ali extract caused a 5 % increase in lean body mass in the treatment group whereas, there were no significant changes in the placebo group. Another major benefit of Tongkat Ali is that Taiwanese scientist have isolated 10 biochemical compounds from the roots of this herb which kill cancer cells.