Also known as SLS, Sodium Lauryl Sulfate is commonly found in skincare products. SLS is a surfactant which means it is used in skincare because it allows the oil and water molecules of the product to bind together to create a smooth consistency. This particular surfactant is used often because it is one of the most cost effective & abundant ingredients available.
The outermost layer of our skin is designed to keep harmful and toxic things out of it. This ingredient is toxic to our skin because it weakens the defense mechanism of the skin's outermost layer. For something to be considered harmful, allergenic, or an irritant-it has to fulfill two criteria. It has to have been found in research to irritate human skin, and it has to have the ability to penetrate the skin. SLS checks both of these boxes qualifying it to be harmful, allergenic, and an irritant to skin.
Several studies have been done on the harmful effects of SLS. In Germany, 1,600 patients were tested to see if their skin would become irritated when exposed to SLS. The results showed that over 42% of them developed reaction to it. Another study performed on several volunteers found that over the course of three and a half months, regular contact with SLS caused skin irritation that subsided as soon as they were no longer exposed to it.
It is so commonly known to cause skin irritation that SLS is used as a positive control in dermatological testing. When a new product is being tested, it is compared to this known-skin irritant. If someone is sensitive to SLS they will find that the exposed area of skin will become itchy, sore, red, or dry and flaky.
So now for the second part of this blog-how in the heck is it still able to be used in skincare products?! The reasoning behind why it is still able to be used is that generally, these skincare products are washed off the skin and it is assumed that they won't be on the skin for very long. If the SLS-containing ingredients are not on the skin very long then the chance of a reaction is very low. Rather than banning this ingredient, they set a maximum percentage at which it can be used in skincare products. The percentage that can be used is directly dependent on how long the product will be in contact with skin. If the product will be in contact with the skin for extended periods of time the percentage of SLS that can be used is substantially lower than if it will only be in contact with the skin for a short period of time. If this ingredient is used in a product, the manufacturer is required to put any adverse findings as well as warnings on the label.
It is important to read the ingredient labels of the skincare products you use to make sure they will not cause any irritation. If you are unsure of how to read skincare product labels you can quickly learn how by reading our last blog post "How to Decode An Ingredient List".