During the past few years, numerous studies have appeared, showing that prebiotics, probiotics and live enzymes have a positive effect on testosterone production. One study from 2014, had a bunch of researchers give male rodents food that was supplemented with the Lactobacillus Reuteri bacteria. In every measured part of the study, the addition of the bacteria resulted in increased testosterone levels. The even bigger news was that apart from testosterone, there were also increases in the testicles size and weight, as well in the luteinizing hormone levels.