Lye is combined with animal fats to make bar soaps, which may corrode and dry out the skin. Healthy skin needs oxygen and needs to release carbon dioxide. It should not be inhibited. Industrially it is used as a grease component. Is flammable and in high doses my be narcotic.
Tests show it can be a strong skin irritant.
You will find this ingredient in your hand and body lotions along with facial moisturizers. Potentially, SLS is the most harmful ingredient used in personal care products. SLS is used in testing labs as the standard ingredient to irritate skin so that non irritating ingredients can be tested. Test show its danger potential to be great. Dr. Green states that very large amounts of nitrates may enter the blood system from just one shampooing with an SLS based shampoo where nitrates have formed.