What Is Sodium Lauryl Sulfate?
Sodium Lauryl Sulfate (SLS), also called sodium dodecyl sulphate, is a salt made from lauryl alcohol and sulfuric acid that is then neutralized with sodium carbonate. The lauryl alcohol usually comes from coconut or palm kernel oil, giving the ingredient a plant based origin even though the final compound is synthetic.
First introduced in the 1930s, SLS quickly replaced traditional soap in many household and personal care items because it created a richer lather and worked well in hard water. Its low cost and strong cleansing action secured its spot in modern cosmetic labs, where it is still widely used.
To produce SLS, manufacturers start by extracting lauryl alcohol from natural oils. This alcohol is reacted with sulfur trioxide to make lauryl sulfate, which is then neutralized with sodium hydroxide to create the final powdered or liquid form of SLS. The result is a surfactant that lowers the surface tension of water, helping oils and dirt rinse away easily.
You will most often find SLS in foaming products such as shampoos, face cleansers, body washes, toothpastes, bubble baths, shaving creams, exfoliating scrubs and even makeup brush cleansers. Its versatility also allows formulators to use it in sheet masks and peel off masks where quick removal of excess oils is desired.
Sodium Lauryl Sulfate’s Cosmetic Benefits/Uses
In cosmetics SLS plays several key roles that help products perform better and feel more enjoyable to use.
- Cleansing: Acts as a surfactant that lifts away oil, sweat and daily grime so they can be rinsed off with water, leaving skin and hair feeling fresh
- Denaturant: Alters the structure of proteins in a formula which can improve product stability and prevent microbial growth, helping extend shelf life
- Foaming: Generates thick, satisfying lather that spreads product evenly and enhances the sensory experience, making it easier to see where you have applied the cleanser or shampoo
Who Can Use Sodium Lauryl Sulfate
Sodium Lauryl Sulfate works best for people with normal or oily skin and hair because its strong cleansing power quickly cuts through excess sebum and product buildup. Those with dry, sensitive or eczema-prone skin may find it too stripping, as it can remove needed oils and disrupt the skin barrier which could lead to tightness or irritation.
The ingredient is considered suitable for vegans and vegetarians since the lauryl alcohol used to make it usually comes from coconut or palm kernel oil rather than animal sources, and no animal-derived reagents are required in standard manufacturing.
Pregnant or breastfeeding women can generally use products containing Sodium Lauryl Sulfate topically because very little, if any, is absorbed through intact skin. That said this is not medical advice and anyone who is pregnant or nursing should show all personal care products to a qualified healthcare provider to be sure they are right for their individual situation.
Sodium Lauryl Sulfate does not make skin more sensitive to the sun so it is not considered a photosensitizer. It is also compatible with most other common cosmetic ingredients, though very high concentrations of acids or salts in the same formula can reduce its foaming ability.
Potential Side Effects/Adverse Reactions
Side effects and reactions to topical Sodium Lauryl Sulfate vary from person to person. The points below list potential issues yet these are unlikely for most users when the ingredient is used at appropriate levels in a well-formulated product.
- Skin dryness
- Irritation or redness, especially on sensitive skin
- Eye stinging if the product accidentally gets into the eyes
- Scalp flaking when used in shampoos on very dry or eczema-prone scalps
- Increased transepidermal water loss in people with compromised skin barriers
If any unwanted reaction occurs stop using the product and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1/5
Sodium Lauryl Sulfate is water soluble and rinses off easily so it rarely lingers on skin long enough to block pores. It can be irritating at high levels, which might make breakouts look worse due to inflammation, but it does not contain heavy oils or waxes that physically clog follicles. For that reason it sits near the bottom of the comedogenic scale.
Acne-prone users can generally tolerate SLS in rinse-off products like cleansers and shampoos, though some may prefer gentler surfactants if their skin is already inflamed.
Because SLS is rinse-off, any residue is minimal. Leave-on formulas rarely use it, further reducing the pore-clogging risk.
Summary
Sodium Lauryl Sulfate acts as a cleanser, foaming agent and protein denaturant. Its surfactant structure lowers water’s surface tension, letting oils and dirt mix with water so they can be washed away. The same property creates the dense lather people associate with a thorough clean, while its ability to denature proteins helps keep formulas stable.
Thanks to its low cost and strong performance SLS still appears in countless everyday products even as milder alternatives gain popularity. Some consumers avoid it for dryness concerns yet its cleaning power keeps it in wide use.
When used at typical cosmetic levels SLS is considered safe for healthy skin, though those with sensitive or very dry skin might experience irritation. As with any new product it is smart to patch test first to make sure your skin feels comfortable.