One of the recent concerns with soy was that it was raising estrogen levels in women which is associated with a higher risk of breast cancer. Although the University of Connecticut did a study that found that it actually doesn’t increase estrogen levels in women, they also found that it does reduce testosterone levels in men.
Soy was also found to have raised cortisol levels. Cortisol is the hormone released when we are under stress and can lead to things like weight gain. For the best impact on your testosterone levels, be sure to avoid products that have soy in them. Testosterone also helps you sleep, produce red blood cells, and repair cells.