Equine Selenium K is in a Kelp base. Kelp meal is a natural feed supplement derived from a seaweed found only in the North Atlantic Ocean. Rich in micronutrients; it contains over 30 minerals including Boron, Molybdenum, Iodine, Sulphur and Iron, 12 Vitamins, 18 Amino Acids as well as high levels of Alginic Acid.