Sodium lauryl sulfate
What is it?
Sodium lauryl sulfate (SLS) is the sodium salt of lauryl sulfate. It typically appears as a white or cream colored crystal or powder. It may also be called sodium dodecyl sulfate; dodecyl sulfate, sodium salt; and sodium n-dodecyl sulfate.
Sodium lauryl sulfate is frequently confused with sodium laureth sulfate, but the two are distinct ingredients.
What does it do?
Sodium lauryl sulfate is frequently used as a surfactant, or foaming agent. It may also serve as an emulsifier, helping oil based and water based ingredients to stay mixed. In many of our toothpastes SLS is used as a surfactant and helps to properly disperse the ingredients during brushing, and ensures easy rinsing and removal of debris (i.e. food particles).
How is it made?
Sodium lauryl sulfate may be derived from either petroleum based or vegetable based sources. The SLS Tom’s of Maine uses is entirely derived from the vegetable sources of coconut and/or palm kernel oil. The oils can be split into glycerin and the component fatty acids, one of which is lauric acid. The lauric acid is isolated and then hydrogenated to form the lauryl alcohol. Alternately, the whole oil can be esterified and then hydrogenated to form the fatty alcohols of which lauryl alcohol would be isolated by fractionation. The lauryl alcohol is then combined with sulfur which then forms the salt, sodium lauryl sulfate.
What are the alternatives?
Many other surfactants agents exist, including synthetic alternatives and additional naturally derived ones. Many of these ingredients would not be considered by Tom’s of Maine because they fail to meet our Stewardship Model guidelines. We use SLS in many of our products because of its long history of safe and effective use, and because of the volume of scientific substantiation for its safety.
However, for consumers who prefer to use a product without SLS, we offer some SLS-free alternatives. In the past we offered Clean & Gentle toothpaste that used glycyrrhizin, derived from licorice root, to foam and disperse ingredients, but that product was discontinued as consumers told us it did not meet their expectations. Our Botanically Bright™ and Botanically Fresh™ toothpastes use our best performing SLS alternative, a blend of Sodium Cocoyl Glutamate and Lauryl glucoside, which are other naturally derived dispersants from coconut or palm kernel oil and corn.
Is this the right option for me?
SLS can be irritating if two conditions exist – it is present at high concentrations and left on the skin for an extended period of time. We use SLS only at the levels needed to deliver on its intended purpose, and these conditions are unlikely to occur with our products. Regardless, individuals who are prone to canker sores or who have a known sensitivity to SLS should seek an SLS-free alternative.
Of all the ingredients we use, Tom’s of Maine tends to receive the highest volume of questions about our use of SLS. This may partly be fueled by the volume of misinformation currently available on the internet. Sodium lauryl sulfate is used in a variety of products, and has a long history of safe use. SLS is approved for use as a direct additive to food by the United States Food and Drug Administration (FDA) when used as a surfactant, whipping and wetting agent or as an emulsifier1. In 2003, the US Department of Health and Human Services evaluated the safety of SLS concluding that SLS is safe for use in oral care products2. SLS is also permitted for use in all cosmetics in the European Union (EU) without restrictions3.
Tom’s of Maine recognizes that no two people are alike, and even with naturally derived ingredients, some individuals may develop an allergic reaction that is unique to them. As with any product, be sure to discontinue use if you experience discomfort or other indications that the product may not be appropriate for your individual body chemistry.
1 21CFR 172.822
2 Tentative Final Monograph 21CFR 356