Sodium cocoyl sarcosinate is the sodium salt of cocoyl sarcosine, which is a modified fatty acid classified as an acyl sarcosine. In skin and hair care products, sodium cocoyl sarcosinate functions as an anionic surfactant. A surfactant works by lowering the surface tension between two substances, such as two liquids or a liquid and a solid. A surfactant molecule contains one end that is hydrophilic (attracted to water) and one end that is lipophilic (attracted to oil). This allows surfactants to attract and suspends oils, dirt, and other impurities that have accumulated on the skin and wash them away, leaving the skin clean. Anionic surfactants are those that have a negative charge on their polar head group, and are most useful for applications that require good cleansing and foam. Sodium cocoyl sarcosinate is particularly mild, and is suitable for sensitive skin and sensitive areas.  It also improves foam and thickening properties of formulations. When used in hair care products, sodium cocoyl sarcosinate has the ability to enhance the appearance and feel of hair by increasing hair body, suppleness, and sheen, or by improving the texture of hair that has been damaged physically or by chemical treatment.