Sodium Lauryl Sulfate (SLS): Is It Bad for Skin?
Sodium lauryl sulfate (SLS) is a strong foaming cleansing agent used in washes, shampoos and toothpaste. The main safety review clears it for brief contact that is rinsed off, and advises keeping it to 1% or less where it stays on skin.
TL;DR
- What it is: a detergent that makes thick foam and lifts oil and dirt.
- Where you find it: face and body washes, shampoos and toothpaste.
- What the review says: fine for brief, rinse-off use, with 1% or less if it stays on skin.
- The catch: irritation tends to rise with concentration and contact time.
- Who should skip it: dry, reactive or tight-feeling skin.
- Our position: we don't currently use it.
What is sodium lauryl sulfate?
SLS is a surfactant, a cleaning molecule with an oil-loving end and a water-loving end. That structure lets it grab oil and dirt, then rinse away with water.
It is also the reason a cleanser foams so generously. Lots of lather feels like a proper clean, which is why it has stayed popular for decades.
Is SLS bad for your skin?
Not in the dramatic way the internet suggests, and not harmless either. The Cosmetic Ingredient Review (CIR) concluded in 1983 that SLS and ammonium lauryl sulfate appear safe in formulas designed for brief use, followed by thorough rinsing.
For products that stay on skin longer, the same report advises concentrations of 1% or less. That is a statement about dose and contact time, which is exactly what matters in a cleanser.
A sister report on sodium laureth sulfate (SLES) notes that eye and skin irritation can occur and tends to rise with concentration. SLS sits in the same family, so it is a fair guide.
Want a cleanser without sulfates? Our Antioxidant Botanical Gel Cleanser is one option, or take the skin quiz to find a routine that suits your skin.
How does SLS compare with other cleansing agents?
| Ingredient | Type | Where you meet it |
|---|---|---|
| Sodium lauryl sulfate | Alkyl sulfate | Foaming washes, toothpaste |
| Sodium cocoyl isethionate | Acyl isethionate | Cleansers and cleansing bars |
| Decyl glucoside | Alkyl glucoside | Face and body washes |
| Cocamidopropyl betaine | Amphoteric surfactant | Co-surfactant in washes |
Most washes blend more than one of these. The mix, not a single ingredient, decides how a cleanser feels.
How do you spot SLS on a label?
Look for "Sodium Lauryl Sulfate", or "Sodium Lauryl Sulphate" on some packs. Sodium laureth sulfate is a different, related ingredient.
- Aqua, Sodium Lauryl Sulfate, Cocamidopropyl Betaine, Glycerin: SLS in the first few slots usually means it is the main cleansing agent.
- ...Parfum, Sodium Lauryl Sulfate: near the end suggests a minor role.
Position is a rough guide to amount, not a percentage.
Who should skip SLS or go slow?
Skip it if your skin feels tight or stings after washing, or if your barrier is already compromised. Dry, reactive and eczema-prone skin usually does better with gentler cleansing agents.
Leave-on products are a different matter. If SLS shows up in something you do not rinse off, check where it sits on the list and be cautious.
How do you use a product with SLS?
Lather briefly, rinse thoroughly and do not leave it sitting on your skin. That mirrors the conditions the safety review was built around.
Patch test any new cleanser first. Our patch testing guide shows how.
Do we use SLS at Dope Skin Co?
We don't currently use it, and it is not in any of our formulas. Our cleansers use other cleansing agents, including sodium cocoyl isethionate and cocamidopropyl betaine.
FAQ
Is SLS the same as SLES?
No. They are related but separate ingredients, and each has its own CIR report.
Is sulfate-free automatically better?
Not automatically. The whole formula, how long it stays on skin and how your skin reacts all matter.
Is SLS in toothpaste too?
Often, yes. Check the ingredient list on your tube.
Why does my skin feel tight after a foaming wash?
Strongly cleansing washes can leave some skin feeling stripped. If that is you, try a gentler cleanser.
Related ingredients
Sources
- Final Report on the Safety Assessment of Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate. Cosmetic Ingredient Review, Journal of the American College of Toxicology, 1983;2(7):127-181
- Final Report on the Safety Assessment of Sodium Laureth Sulfate and Ammonium Laureth Sulfate. Cosmetic Ingredient Review, 1983
