MSM is comprised of 34% bio-available sulfur, making it the richest source of organic sulfur available. Sulfur is critical in the formation of collagen and glucosamine which are vital components for healthy bones, joints, ligaments and tendons. MSM is also recommended by veterinarians for animals with arthritic conditions. Guaranteed Analysis: Analysis per tablet: Methylsulfonylmethane - 500 mg. Ingredients: Pure Methylsulfonylmethane. Directions: ANIMAL WEIGHT DAILY AMOUNT: Dogs to 30 lbs 1 tablet, 31 to 59 lbs. 2 tablets, 60 + lbs. 3 tablets.