SLS (Sodium Lauryl Sulfate or Sodium Laurel Sulfate) and SLES (Sodium Laureth Sulfate) are harsh detergents often derived from petroleum. They are used in facial cleansers, body washes and shampoos for their ability to cleanse and create a foaming lather and that “squeaky-clean” that consumers associate with cleanliness. But, this is one example where you can be “too” clean, as several studies prove that SLS and SLES can strip skin of moisture and irritate the skin and eyes, causing sensitivity and allergic reactions.
Did you know?
The SLS in industrial cleansers used to clean garage floors, degrease car engines and wash cars is the same as you find in many soaps, body washes and facial cleansers. It is also used in scientific studies to help measure the degree of irritation of other ingredients. So why would companies use for skincare? The answer is simple – it is cheap.
In the same way as they dissolve grease, SLS and SLES dissolve the oils on your skin, removing natural oils from the lipid layer which breaks down the acid mantle of the skin. This causes dryness, dehydration and tight, flaky skin.
It is well documented that these detergents damage the skin barrier and denature skin proteins, which causes irritation and allows environmental contaminants easier access to the lower, sensitive layers of the skin. This leaves the skin rough and vulnerable to photo-aging and other skin diseases. While this denaturing of skin proteins is implicated in skin and other cancers, and is corroborated by several health advocates, the American Cancer Society states that SLS and SLES do not cause cancer.
SLS vs. SLES
SLES (Sodium Laureth Sulfate) is simply SLS (Sodium Lauryl Sulfate) that has been ethoxylated to make it milder and less abrasive. While some sources indicate only SLS is the villain, most informed sources agree that SLES creates a harmful compound linked with cancer. According to the Cosmetic Ingredient Review, SLES can be contaminated with 1,4-dixoane and ethylene oxide. Research shows that 1,4-dioxane readily penetrates the skin and is considered a probable human carcinogen by the U.S. Environmental Protection Agency. It is included on California’s Prop. 65 list of chemicals known or suspected to cause cancer or birth defects and the National Toxicology Program lists it as an animal carcinogen. Note: This ingredient isn’t seen on labels but is created when certain ingredients are combined via ethoxylation.
While some sources vilify all sulfates, ammonium lauryl sulfate and ammonium laureth sulfate sourced from coconut oils are considered non-toxic and non-irritating by others. As with any controversial ingredient, choosing what to avoid is completely personal.
Just as with alcohol, this stripping of the skin’s natural oils can lead to rebound oil production, creating a vicious cycle. Instead, choose cleansers with natural surfactants, that are gentle and effective.