Nu-Hoof Maximizer A supplement for horses formulated with biotin, folic acid, riboflavin, lysine, methionine, copper, zinc, and direct-fed microbials. Key nutrients for hooves are believed to be zinc, copper, iodine, lysine, methionine, folic acid, riboflavin, and biotin. While these ingredients work dramatically when in balance with each other, they work only marginally when supplemented individually. With that in mind, it is important to understand how each essential nutrient works.