SLS / SLES
Sodium lauryl sulfate / sodium laureth sulfate
Also seen as: sodium lauryl sulfate, SLS, sodium laureth sulfate, SLES, sodium dodecyl sulfate
At a glance
SLS and SLES are foaming and cleaning agents (surfactants) — they're what makes shampoo and body wash bubble up. They're well-established skin and eye irritants, especially in people with sensitive skin or eczema. The internet myth that they cause cancer is not supported by the evidence. The legitimate concern with SLES specifically is that it can be contaminated with trace 1,4-dioxane (a probable carcinogen) during manufacturing — a separate issue some brands actively work to remove.
Quick facts
- What it isAnionic surfactants (foaming cleaners)
- Main jobCreate lather, dissolve and lift dirt and oil
- How exposure happensSkin contact, eye contact
- Most relevant forSensitive skin, eczema, dry scalp, mouth ulcers, dry-eye sufferers
- Easy to spot?Yes — listed by name on ingredient lists
- US snapshotFDA permits in cosmetics. 1,4-dioxane contamination in SLES is monitored.
- EU snapshotAllowed in cosmetics. 1,4-dioxane contamination limits set.
- Global contextSome advocacy groups campaign against SLS/SLES, but the cancer claim originates from a 1990s misreading of toxicology data and has been repeatedly debunked.
Where it commonly shows up
- Personal CareShampoo, Body wash, Hand soap, Bubble bath, Shaving foam
- Cosmetics & MakeupSome makeup removers, Some face washes
- Oral CareToothpaste — most foaming toothpastes contain SLS
- Baby & KidsSome baby washes and shampoos (many have moved to gentler alternatives)
- Kitchen & FoodDishwashing liquid
- Cleaning & LaundryLaundry detergent, Surface cleaners
- Clothing & TextilesNot typical in finished products
- Home & LivingSome carpet cleaners
- Other Daily ItemsCar wash soaps, Industrial cleaners
What to do about it
If you have an itchy scalp, dry skin, eczema, or mouth ulcers, try a week of SLS-free shampoo and toothpaste. Many people see significant improvement.
Better choices
- Sulfate-free shampoos for sensitive scalps
- SLS-free toothpaste if you get mouth ulcers
- For SLES-containing products: brands that specifically state '1,4-dioxane-free' have done extra processing
Common questions
Each answer is tagged with how settled the evidence is: Established, Estimate, or To check.
What are SLS and SLES in simple terms?Established
Foaming agents. They're what makes shampoo, body wash, and toothpaste bubble up. SLS (sodium lauryl sulfate) is more irritating; SLES (sodium laureth sulfate) is milder but can be contaminated with trace 1,4-dioxane from manufacturing. Both are workhorse cleaning ingredients used in thousands of products.
Why is it used in everyday products?Established
Cheap, effective foamers and cleaners. Foam itself isn't necessary for cleaning, but consumers expect it — a product that doesn't foam well 'feels' like it isn't cleaning. SLS/SLES deliver that foamy experience at low cost.
What names does it go by on product labels?Established
Sodium lauryl sulfate (SLS), sodium dodecyl sulfate (SDS — same chemical), sodium laureth sulfate (SLES), sodium lauryl ether sulfate. Related: ammonium lauryl sulfate. 'Sulfate-free' products avoid all of these.
Where do we commonly find it at home?Established
Shampoo, body wash, toothpaste, bubble bath, dishwashing liquid, laundry detergent, and many household cleaners.
How does it enter the body?Established
Skin and eye contact. Systemic absorption is minimal. The issue is local irritation, not internal toxicity.
How does it affect women, especially during pregnancy?To Check
No pregnancy-specific concerns. Skin sensitivity often increases during pregnancy, so the irritation effect may feel worse. If you're getting unexplained scalp itch or skin irritation during pregnancy, an SLS-free swap is reasonable.
How does it affect men's health and fertility?To Check
No fertility concerns documented. Same skin-irritation issue.
How does it affect babies, children, and teenagers?Estimate
Kids with eczema or sensitive skin are the main concern group. Many baby brands have moved to milder surfactants for this reason. For SLS-free toothpaste — useful if a child gets recurring mouth ulcers.
Does it affect older adults differently?To Check
Aging skin tends to be drier and more reactive. SLS exposure can worsen dryness and itching.
What does the strongest evidence say?Established
Strong evidence for skin and eye irritation — SLS is widely used as a positive control in skin irritation studies because it's so reliably irritating. The cancer claim circulating online is not supported — the original 1990s memo it traces to was a misreading, repeatedly debunked since. The 1,4-dioxane contamination issue in SLES is real but a manufacturing question that can be addressed by extra purification.
How serious is the risk from normal daily use?Estimate
Low for most people. Moderate for anyone with eczema, sensitive skin, or recurring mouth ulcers. The 1,4-dioxane question in SLES is real but the concentrations after manufacturing controls are typically very low.
What are safer alternatives?Established
Sulfate-free shampoos and body washes use gentler surfactants (cocamidopropyl betaine, decyl glucoside, coco glucoside, sodium lauroyl sarcosinate). Many widely available. For toothpaste: SLS-free options often labelled 'for sensitive mouths'.
How easy or hard is it to avoid?Estimate
Easy — sulfate-free is a common label claim and the options are wide.
What's one simple first step right now?To Check
If anyone in your home has eczema, dry scalp, or recurring mouth ulcers, swap their main daily product (shampoo or toothpaste) for an SLS-free version for a few weeks. Often a dramatic improvement.
What this means for youEstablished
Don't worry about cancer claims — that's a myth. Do consider an SLS-free swap if anyone in the house has sensitive skin or recurring mouth ulcers. For everyone else, SLS in shampoo is a comfort question, not a hazard question.
Where can I find reliable information?To Check
FDA on sulfates in cosmetics, FDA on 1,4-dioxane in cosmetics, peer-reviewed dermatology literature on irritant contact dermatitis. See References below.
Related guides
Formaldehyde ReleasersFragrance CompoundsOptical BrightenersNonylphenols / Alkylphenol EthoxylatesPEG CompoundsSurfactants Beyond SLS / SLESFragrance FreeSLS Free / Sulfate Free
Sources
Micro Detox is an educational exposure reduction guide. It is not medical advice and does not diagnose, treat, prevent, or cure any condition. If you are pregnant, trying to conceive, or managing symptoms, speak with a qualified health professional.
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