TL;DR
Sodium laureth sulfate (SLES) is a close cousin of SLS that has been ethoxylated, which generally makes it milder but adds a manufacturing byproduct, 1,4-dioxane, that responsible brands test for. SLES is not the same ingredient as SLS, but it does the same job: creating foam by pulling oil and dirt off skin. If you prefer to skip both, plant-based surfactants like soapwort are an alternative worth knowing about.
You've read the label, spotted "sodium laureth sulfate," and wondered whether it's the same thing as the SLS you've been avoiding. It's a fair question, and the marketing rarely helps. Many baby washes proudly say "SLS-free" on the front and then list SLES on the back.
Here's what sodium laureth sulfate (SLES) actually is, how it differs from SLS, and how to decide what feels right for your family.
What Exactly Is Sodium Laureth Sulfate (SLES)?
SLES is a synthetic surfactant made from lauryl alcohol, usually derived from coconut or palm kernel oil, that is reacted with ethylene oxide and then converted into a sulfate salt. A surfactant is the ingredient that lets water grab onto oil and dirt so they rinse away. SLES creates the rich, bubbly lather many people associate with a "clean" feeling.
How Is SLES Different From SLS?
SLS (sodium lauryl sulfate) is the original; SLES is SLS that has gone through ethoxylation, which adds a short chain of ethylene oxide units to the molecule. That change makes SLES larger and generally less irritating to skin than SLS, which is why it's so common in products marketed as gentle. They are separate ingredients with separate profiles, so "SLS-free" does not mean "sulfate-free."
Why Do Some Parents Pay Attention to 1,4-Dioxane With SLES?
Ethoxylation can leave trace amounts of 1,4-dioxane, an unintended byproduct that is not added on purpose and does not appear on the label. The EPA considers 1,4-dioxane likely to be carcinogenic to humans at high exposures, and regulators have taken notice: the FDA monitors it in cosmetics, and New York State has set limits for it in personal care products. Levels in finished products are typically low, and manufacturers can reduce it with a purification step called vacuum stripping.
This isn't a reason to panic. It's a reason to know the question exists, especially for products used on babies, whose skin is thinner and who have more skin surface relative to their body weight. The same byproduct concern applies to other ethoxylated ingredients like PEGs, which we cover in our PEG and 1,4-dioxane guide on this blog.
Is SLES Irritating for Baby Skin?
SLES is generally better tolerated than SLS, but it is still a sulfate surfactant, and strong surfactants can strip skin's natural oils, especially in cleansers used daily or left on too long. Babies with dry or eczema-prone skin may be more sensitive to any foaming cleanser. If your child's skin seems tight, red, or itchy after bath time, it's worth looking at the surfactant on the label, and it's always worth checking with your pediatrician about persistent skin concerns.
What Are the Alternatives to Sulfate Surfactants?
Gentler cleansers include plant-derived options such as soapwort, a traditional cleansing plant whose natural saponins create a soft, low-foam lather. Our Baby Shampoo & Body Wash uses soapwort in place of SLS, with no synthetic fragrance. The trade-off is honest: plant-based cleansers lather less, and that's because the lather isn't being engineered. Foam is not what cleans; it's just what we're used to.
How Can You Check Your Baby's Wash Label for SLES?
Scan the ingredient list for "sodium laureth sulfate," "sodium lauryl sulfate," "ammonium laureth sulfate," or anything with "-eth-" followed by a number (like "laureth-7"). The "-eth-" in a name signals ethoxylation. Ingredients are listed in descending order by amount, so a surfactant near the top is a main cleanser rather than a trace addition.
Frequently Asked Questions
Is SLES the same as SLS?
No. SLES is made by ethoxylating SLS, which makes it milder but adds a possible 1,4-dioxane byproduct. Both are sulfate surfactants.
Is SLES safe for babies?
Regulators allow SLES in cosmetics, and it is considered safe at typical use levels. Some parents choose to avoid it because of potential skin sensitivity and the 1,4-dioxane question. It's a personal choice, and checking with your pediatrician is wise for sensitive skin.
Does "sulfate-free" mean a baby shampoo is gentler?
Not automatically. It means the product doesn't use sulfate surfactants, but the replacement cleanser and the rest of the formula still matter. Read the full label.
Why does natural baby wash lather less?
Plant-based cleansers like soapwort produce a lighter lather than sulfates do. Less foam doesn't mean less cleaning.
Do I need to throw out products with SLES?
No. You can use up what you have and choose differently next time, at your own pace.
Knowing the difference between SLS and SLES puts the label back in your hands. If you're ready to try a plant-based alternative, you can explore our Baby Shampoo & Body Wash at shopkindrednaturals.com.
Written by Mike & Carly Pronsky, founders of Kindred Naturals.