Sulfur is an indispensable element in human nutrition. As part of the amino acids methionine and cysteine, sulfur is required for the structural integrity and function of almost every protein in the body, including enzymes, serum proteins, and the keratin of skin, hair, and nails. Sulfur is also an essential element for the glycosaminoglycans of connective tissues and cartilage, and assumes a major role in liver detoxification as part of the hepatic sulfur conjugation pathways. Proper detoxification of xenobiotics, such as phenols, and many endogenous and foreign food- or air-borne compounds depends on an adequate supply of biologically active sulfur. Dietary MSM serves as a versatile donor of metabolically active sulfur for the synthesis of numerous organosulfur compounds and proteins in the body. As such, MSM helps maintain normal immune response, lung function, connective tissue metabolism, and muscle contraction. MSM occurs naturally in a variety of foods, such as fruits, vegetables, cereal grains, milk, and fish. However, MSM is volatile and easily lost during cooking. MSM is very well absorbed by the intestinal tract and rapidly distributed within the body.