Inci of cosmetics, you know what you are applying on skin Part 12, the sodium lauryl sulfate
Sodium lauryl sulfate is a surfactant used in shampoo, shower gel, soaps and after shave lotions, it results very aggressive and irritating on skin, possible cause of acne, dry skin and dandruff.
Cosmetic products are not all the same and the difference, for our health and beauty, isn’t given by the price or the best advertising, but by the ingredients that you find inside creams, serums, soaps and shampoos. Sometimes the used ingredients respect the skin and the hair, other times, and unfortunately this happens quite often, not at all and the results are irritations, dull skin, wrinkles but also acne, blackheads and, for what concerns hair, dandruff, oily scalp, hair loss and brittle hair. What can we do? Recognizing the most aggressive substances by reading the INCI, the label that lists all the ingredients of a cosmetic, and avoiding them can be really a big help. Today we will speak about the sodium lauryl sulfate.
Sodium lauryl sulfate
This substance, also known as sodium dodecyl sulfate, SLS or SDS, appears in the INCI with the name Sodium lauryl sulfate. It is a detergent surfactant and a very effective foaming agent, for this reason it is used in preparations such as soaps, shampoos, shower gel or after shave lotions. The substance promotes the removal of oil from skin, it is cheap and largely used in detergents but it is also very aggressive. According to a scientific study of some years ago indeed (Patil et al, Journal of pharmaceutical science, 1995), this substance penetrates into the skin and can be found in the tissues for a long period after the application, about a week after 24 h of application, as has happened during the experiment. This causes the destruction of the skin barrier for a long time (Torma et al, J Invest dermatol, 2008). In the daily use there isn‘t a so long continuative application and for this reason the residence time in the tissues is lower but these data are useful to understand that the effect of sodium lauryl sulfate is prolonged in time and if this substance appears in cosmetics that are used more times a day in sensitive parts such as the face then the irritating effect is continuous. As a consequence of the use of detergents that contain SLS the skin reacts with irritations and inflammations, and this is reported by scientific studies that have also observed that the more sensitive and reactive parts of skin are, in both young and older people, forehead, cheeks and chin (Marakchi et al, Skin Pharmacol Physiol, 2006). A prolonged use of products that contain SLS may damage the hydrolipidic film of the skin and causes dry and dehydrated skin, red skin but also acne and blackheads and, for hair, dandruff and oily hair. Based on these considerations, a good choice may be to avoid cosmetic products that contain sodium lauryl sulfate, especially when they are part of our daily beauty routine. There are products that use natural detergents, more delicate but effective, such as that derived from sugar or coconut (for example Coco Glucoside, Cocamidopropyl Betaina and Decyl Glucoside from coconut oil, Gliceryl Oleate from plant based oils and sugar). In alternative, especially for an acne prone skin, you can take into consideration the possibility to clean your face with the oil cleansing technique, we spoke about it in previous posts.