500 mg Pure, Nutrient Rich Spirulina is a blue-green microalgae that has naturally occurring protein, plus other nutrients such as vitamins, minerals and GLA (gamma-linolenic acid). NOW® Certified Organic Spirulina Tablets are pure and contain no excipients, binders, or additives. NOW® Spirulina delivers the natural nutrient profile found in genuine whole foods. Natural color variation may occur in this product.