What SLS-Free Actually Means (And What It Doesn't)
THE SHORT ANSWER
SLS-free means a product contains no Sodium Lauryl Sulfate. It does not necessarily mean the product contains no sulfates at all. Those two claims get used interchangeably in marketing, and they shouldn't be.
We're SLS-free. We are not sulfate-free, and we'd rather tell you that plainly than let you assume otherwise.
What is SLS?
Sodium Lauryl Sulfate is a surfactant — a molecule that lets water lift away oil and dirt. It has been a mainstay of shampoos, washing-up liquids and toothpastes for decades because it is cheap, produces a thick satisfying lather, and cleans very effectively.
That effectiveness is also the issue. SLS is a small molecule with a strong affinity for the proteins and lipids on the skin's surface. On some people, particularly those with sensitive or reactive skin, it can leave the scalp feeling tight or itchy after washing. It is used as a standard irritant control in dermatological patch testing precisely because its effect on skin is so reliable and well documented.
It's worth saying clearly: SLS is not dangerous, and it is not banned. The claims circulating online that it is carcinogenic have no basis. It's simply a harsh cleanser, and for fine hair and young or sensitive scalps we didn't think it was the right choice.
So what's the difference between "SLS-free" and "sulfate-free"?
"Sulfate" is a whole family of surfactants, not a single ingredient. SLS is one member of it. Others include Sodium Laureth Sulfate (SLES), Ammonium Lauryl Sulfate, and Sodium Coco-Sulfate.
| SLS-free | One specific ingredient is absent. |
| Sulfate-free | The entire family is absent. |
A product can honestly be SLS-free while still containing a sulfate. This is extremely common, and it's where a lot of shelf copy gets slippery — brands lead with "SLS-free" on the front and let shoppers infer "sulfate-free," which is a different and stronger claim.
What we use instead
Our shampoo uses Sodium Coco-Sulfate. It is a sulfate. We're not going to pretend otherwise.
It's derived from coconut oil, and it's made up of a blend of chain lengths rather than the single short chain that makes SLS so aggressive. The resulting molecule is larger on average, which means it sits differently against the skin and is generally considered gentler than SLS. It still produces a proper lather — which matters more than people admit, because a shampoo that doesn't foam doesn't feel like it's working, and children in particular notice.
Could we have gone fully sulfate-free? Yes. But the alternatives we tested either didn't clean well enough to lift a day of nursery off fine hair, or produced so little lather that the wash took twice as long — which, if you've ever washed a three-year-old's hair, is not a neutral trade-off.
We'd rather have a slightly more complicated story than a cleaner-sounding one.
How to read a shampoo label yourself
Ingredients are listed in descending order by weight, down to 1%, after which order is arbitrary. Water is almost always first. The surfactants usually appear in the next two or three positions.
- Look for the INCI name, not the marketing name. INCI is the standardised international naming system, and it's what appears on the back of the bottle. "Gentle coconut cleanser" on the front tells you nothing; the INCI list tells you everything.
- "Free-from" claims are selective by nature. A brand chooses which absence to advertise. The presence list is more informative than the absence list.
- "Natural" and "botanical" are not regulated terms in the way "organic" is. They describe a direction of travel, not a standard.
- Position matters. An ingredient listed after the fragrance is present in a very small amount.
Does any of this matter for children?
Children's scalps are not miniature adult scalps. The skin barrier continues developing through the early years, and fine hair means a wash reaches the scalp more directly than it does through thick adult hair. A milder surfactant is a sensible default rather than a luxury.
It's also worth remembering that how you wash matters as much as what you wash with. Most children's hair needs washing far less often than adults assume — two or three times a week is plenty for most, and over-washing is a more common cause of a dry, irritated scalp than any single ingredient.
If your child has a persistent scalp condition, eczema, or a diagnosed sensitivity, speak to your GP or health visitor before changing products. No shampoo is a treatment, ours included.
Our shampoo and conditioner are SLS-free, made in small batches, and crafted in England. They contain Sodium Coco-Sulfate. Both of those things are true at once, and you deserve to know both before you buy.
See the full ingredient list