Sodium lauryl sulfate (C12H25NaO4S, is called SLS for short) is a chemical compound used in personal care products, perfumes and cleaning detergents. The U.S. Food and Drug Administration listed it as a food additive and specified regulations and limits of its use. The chemical has been a controversial topic on the Internet as some health advocates purport its possible adverse effects on people.
Its role in these products is usually that of a foaming or a dispersal agent. For example, toothpaste or bubble baths that foam when used contain sodium lauryl sulfate, as well as products that need its components dispersed homogeneously, such as fragrance oils in body spray.
Clinical tests on rabbits demonstrated that 10 percent of sodium lauryl sulfate caused corneal impairment, especially if the chemical was not rinsed out of the eye, according to the Journal of American College of Toxicology. Rinsing reduces irritation to a degree, and if it’s not done promptly, then the damage is severe. Absorption and metabolism studies showed that SLS can destroy properties of proteins, causing deterioration in cell membranes.
According to the Journal of American College of Toxicology, human skin tests conducted showed that skin irritation was directly related to SLS concentration——the higher the concentration, the greater the irritation. It was concluded that the chemical’s contact with human skin should not exceed 1 percent. Additional tests conducted on rabbits found that SLS concentrations of .5 to 10 percent caused slight to moderate skin irritations, and concentrations of 10 to 30 percent caused severe aggravations.
Besides subjecting human and animal test subjects to different degrees of discomfort, critics claim that SLS is retained in the long run in organ tissues like the heart, liver, and brain. In lab animals, testing has been blamed for causing mutagenic effects. If they remain in the eyes for too long, they may also lead to the development of cataracts. Because sodium lauryl sulfate(CAS No. 151-21-3) is corrosive by nature, it can dry out skin by stripping the protective lipids from the surface of the skin, weakening the body’s natural moisture regulation mechanisms. If it eats away at the follicle, hair loss may also be induced.
It has arguably been called one of the most dangerous ingredients in products today. Household essentials like cosmetic cleansers, bath gels, shampoos, and dishwashing detergents contain up to fifteen percent sodium lauryl sulfate. In extreme cases, SLS is argued to be carcinogenic, though not by itself. When exposed to other nitrogen-bearing ingredients of a skin product though, the oxidation reaction that results may form nitrosomines, which are carcinogenic nitrates.