Selenium 100mcg by Source Naturals Inc. 100 Tablet Recent clinical studies suggest that Selenomax high-selenium yeast is the preferred form of the antioxidant selenium. This special food-form selenium from nutrition 21 is certified to be organically bound to natural yeast cells as in nature. This provides a vastly improved rate of assimilation compared to inorganic selenium. Selenium is recognized as an essential trace mineral. Its recommended safe and adequate daily intake is 50 mcg -200 mcg. The upper range should not be habitually exceeded.