Soy and soy-based products

According to some studies, consuming soy products including edamame, tofu, soy milk, and miso on a daily basis may induce a reduction in testosterone levels. One research of 35 males, for example, discovered that consuming soy protein isolate for 54 days resulted in lower testosterone levels. Soy meals are also strong in phytoestrogens, which are plant-based compounds that mimic estrogen's effects in your body by modifying hormone levels and potentially lowering testosterone. Despite the scarcity of human-based data, one rat study found that eating phytoestrogens drastically reduced testosterone levels and prostate weight.

Other studies, however, produced contradictory results, indicating that soy-based diets may not have the same effect as these separated soy components. Indeed, a meta-analysis of 15 trials concluded that soy meals had no influence on testosterone levels in men. More study is needed to determine how soy products in general may affect testosterone levels in humans.