The Mystery of Sodium Dodecyl and Laureth Sulfates

Every morning we wake up and the first thing that we do is brush our teeth. But have you ever wondered what do the tube of toothpaste and the bar of soap that we use contain? Well they contain a substance called as SDS. Let us find out more about this substance.

SDS is on your hands and in your mouth too! You wake up every morning and brush your teeth. But have you ever wondered what your toothpaste or a bar of soap contains? Well, they contain a substance known as SDS.

What is SDS?
Sodium dodecyl sulphate (SDS), also known as sodium lauryl sulphate (SLS), is a
substance found in toothpaste, liquid soaps and detergents and is used for different protein studies in Biochemistry. In its purified state, SDS is a white powder of medium molecular weight (M.W. or F.W. of 288.38, C12H25O4SNa). A modified form of SDS is sodium laureth sulphate (M.W. or F.W. 418.53, C12+2nH25+4nNaO4+nS). Both these compounds have a lot of scientific and household uses.

In the Lab
SDS is used during the protein purification process and is used for studying the
protein molecular weights by a technique called polyacrylamide electrophoresis (PAGE). Proteins are dissolved in a solution of SDS, which is an anionic detergent that binds one SDS molecule to every two amino acid residues in the entire protein molecule.

Sodium dodecyl sulphate (the CAS number is 151-21-3) is a detergent that promotes a linear or a straightened, non-globular configuration of the native proteins. Cross-linking disulfide covalent bonds in the protein are broken by the use of mercaptoethanol (2-thioethanol) or dithiothreitol. These chemical treatments permit different types of proteins, which are characterized and defined according to their specific molecular weight.

In the Home
SDS plays an important role in homes as they have foaming characteristics that are used
in toothpastes, liquid hand soaps and liquid detergents.

Toothpastes commonly contain SDS that helps separate, free and remove food and debris in and around the teeth and gums helping prevent tooth decay and pyorrhea of the gums. Hand washes, liquid soaps and some laundry detergents use SDS to remove dirt and debris.

Dangers Of Sodium Lauryl Sulfate

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.