By Dr. Channa Jayasumana
Department of Pharmacology, Faculty of Medicine, Rajarata University,
Sodium Lauryl Sulfate (SLS) and its close relative Sodium Laureth Sulfate (SLES) are inexpensive detergents commonly used in cosmetic cleansers, hair shampoos, bath and shower gels, soaps shaving creams, mouth washes and toothpastes. It is probably the most dangerous ingredient used in skin and hair-care products.
In the cleaning industry SLS is used in toilet cleaners, garage floor cleaners, engine degreasers and car wash soaps, it is very corrosive and readily attacks greasy surfaces. Far from giving "healthy shining hair" and "dirty less skin", soaps and shampoos containing sodium Laureth sulfate can lead to direct damage to the hair follicle, skin damage, permanent eye damage in children and even liver toxicity. Hence recently its use in health care products has been banned in many countries. But still it is a main component in shampoo, bath gels etc available in the Sri Lankan market.
Sodium lauryl sulfate is used throughout the world for clinical testing as a primary skin irritant. Laboratories use it to irritate skin on test animals and humans so that they may then test healing agents to see how effective they are on the irritated skin.
A study at the University of Georgia Medical College indicated that SLS penetrated the eyes as well as the brain, the heart and the liver and showed long-term retention in the tissues. The study also indicated that SLS penetrated young children’s eyes and prevented them from developing properly and caused cataracts to develop in adults.
SLS dries skin by stripping the protective lipids from the surface so it can’t effectively regulate moisture. In the same way as it dissolves the grease on car engines, SLES also dissolves the oils on skin, which can cause a drying effect. It is also well documented that it denatures skin proteins, which causes not only irritation, but also allows environmental contaminants easier access to the lower, sensitive layers of the skin.
Another extremely serious problem is the connection of SLS with nitrate contamination. SLS reacts with many types of ingredients used in skin products and forms nitrosomines (nitrates). Nitrates are potential cancer-causing carcinogens. Because of the alarming penetrating power of SLS, large amounts of these known carcinogens are absorbed through the skin into the body. Once it has been absorbed, one of the main effects of SLS is to mimic the activity of the hormone oestrogen. This has many health implications and may have contribute for a variety of health problems from post menopausal symptoms and menopausal symptoms to dropping male fertility and increasing female cancers such as breast cancer, where oestrogen levels are known to be involved.
Not only synthetic products, most common brands of "Natural" or "Herbal" shampoos and cleansers still use these harmful chemicals as their main active ingredient. It is known that whether it gets in the eyes or not, skin application does lead to measurable concentrations in the eyes of children. This is known to affect eye development, and the damage caused in this manner is irreversible. If you have children with hair falling problem or a skin problem, you had better not use products containing SLSE or SLS. Moreover, since Sri Lankan law and regulations pertinent to use of this kind of hazardous chemicals are outdated, they must be amended to meet the current world standards.
Courtesy - The Island
