A Lignan is a phytoestrogen (plant estrogen) found in the hulls of flax seed, sesame seeds and other plant sources. This phytonutrient is classed as a polyphenol. They can also be found in rye, barley, seeds, and fresh fruits and vegetables, but flax seed has the highest concentration of lignans found in any natural food source. The main lignan in Flax seed is SDG. When eaten, SDG is converted in the body to enterolactone and enterodial. These two mammalian lignans are linked to better health in both men and women. 5 Month supply