You're standing in the baby aisle, turning over a bottle of shampoo. You read the back label — and somewhere in that long list of ingredients, you spot it: sodium lauryl sulfate. You've heard it's something to watch out for. But is it actually harmful, or is this just more wellness noise?
It's a fair question — and you deserve a straight answer. Let's look at what SLS actually is, what the research says, and why more ingredient-conscious parents are choosing plant-based surfactant alternatives like soapwort for their babies' baths.
TL;DR: SLS (sodium lauryl sulfate) is a synthetic surfactant used in most conventional baby shampoos. While regulatory agencies consider it safe at low concentrations, emerging research points to potential skin barrier disruption and irritation — especially in babies with sensitive skin. Soapwort is a gentle, plant-based alternative that cleanses without stripping. Kindred Naturals' Baby Shampoo & Body Wash uses soapwort instead of SLS, making it one of the few truly transparent options on the market.
What Is SLS — and Why Is It in Almost Every Baby Shampoo?
Sodium lauryl sulfate is a synthetic surfactant — meaning it's the ingredient that makes your shampoo lather and foam. It's cheap, effective, and shelf-stable, which is why it shows up in everything from baby wash to toothpaste to dish soap.
SLS works by breaking down the surface tension between water and oil, lifting dirt and grease off skin and hair. Functionally, it does the job. But the same properties that make it a powerful cleanser are also what raise questions for parents with label-reading habits.
What Does the Research Actually Say About SLS and Baby Skin?
Regulatory bodies like the FDA and the EU's Scientific Committee on Consumer Safety (SCCS) have reviewed SLS and consider it safe in rinse-off products at concentrations under 1–2%. Most baby shampoos fall within this range.
But safe-at-low-doses isn't the same as ideal for a baby's skin. Here's what dermatological research has found:
- Skin barrier disruption: Multiple studies have shown that SLS can degrade the skin's lipid barrier — the protective layer that keeps moisture in and irritants out. A 2005 study published in Contact Dermatitis found that even low-concentration SLS exposure caused measurable damage to the stratum corneum (the outermost layer of skin).
- Irritation in sensitive skin: Babies have thinner, more permeable skin than adults. Their skin barrier is still developing through the first few years of life, making them more susceptible to ingredients that disrupt it.
- Cumulative exposure: SLS is in shampoo, body wash, toothpaste, and countless other daily-use products. The concern isn't one bath — it's daily, repeated contact on developing skin.
None of this makes SLS a villain. But if you're reading labels for a reason, it's a worthwhile ingredient to understand.
Is "SLS-Free" Enough — or Do You Need to Look Deeper?
Here's where it gets nuanced. Many brands reformulate away from SLS only to swap in sodium laureth sulfate (SLES) or cocamidopropyl betaine — both considered gentler, but still synthetic surfactants that warrant scrutiny for truly sensitive skin.
If you're evaluating a "gentle" or "SLS-free" baby wash, look at the full surfactant system — not just the absence of one ingredient. What's doing the cleansing work instead?
What Is Soapwort and Why Does It Matter?
Soapwort (Saponaria officinalis) is a flowering plant that has been used as a natural cleanser for centuries. Its leaves and roots contain saponins — naturally occurring compounds that produce a gentle lather and lift dirt without the harsh stripping effect of synthetic surfactants.
Unlike SLS, soapwort:
- Doesn't disrupt the skin's lipid barrier
- Is biodegradable and plant-derived
- Has been used safely on sensitive and eczema-prone skin
- Produces a softer, less aggressive lather — which is actually what you want for a baby
It's not a marketing claim. It's a different category of ingredient entirely.
At Kindred Naturals, our Baby Shampoo & Body Wash uses soapwort as its primary surfactant — no SLS, no SLES, no synthetic fragrance, no endocrine disruptors. We list every ingredient and we explain why each one is there. That's the standard we hold ourselves to.
How Do You Read a Baby Shampoo Label Like a Pro?
A few things to look for when evaluating any baby wash:
- Surfactant source: Is it synthetic (SLS, SLES, ammonium lauryl sulfate) or plant-derived (soapwort saponins, decyl glucoside, coco glucoside)?
- Fragrance: "Fragrance" or "parfum" on a label can represent a cocktail of undisclosed synthetic chemicals. Look for products that specify the source of any scent.
- Preservative system: Parabens and formaldehyde-releasing preservatives are common in conventional baby products. Look for alternatives like sodium benzoate (at appropriate pH) or products with short ingredient lists that don't require aggressive preservation.
- pH: Baby skin has a naturally acidic pH (around 5.5). Gentle cleansers should be pH-matched to avoid disrupting the acid mantle.
Frequently Asked Questions
Is SLS really that bad for babies?
At regulated concentrations, SLS is considered safe. But for babies with sensitive or eczema-prone skin, the skin barrier disruption it can cause is a real concern worth avoiding. If your baby has reactive skin, switching to a soapwort-based or plant-surfactant wash is a low-effort change that may make a noticeable difference.
What's the difference between SLS and SLES?
Sodium laureth sulfate (SLES) is a milder derivative of SLS — it goes through an additional processing step that makes it less irritating. However, that process can introduce 1,4-dioxane, a potential contaminant. Neither is ideal for babies with sensitive skin.
Is soapwort safe for newborns?
Soapwort saponins used in cosmetic formulations are gentle enough for newborn skin. Because they don't strip the skin barrier, they're actually better suited to a baby's developing skin than synthetic surfactants.
What does "fragrance-free" actually mean on a baby product?
"Fragrance-free" means no fragrance ingredients were added to scent the product. It's different from "unscented," which can mean masking fragrances were used to neutralize odor. Fragrance-free is what you want.
How do I know if a baby shampoo is truly clean?
Look for full ingredient transparency, no "fragrance" on the label, plant-based surfactants, and a brand that explains why each ingredient is included. Certifications like EWG Verified or Made Safe can also help, though they're not the only signal.
If you're ready to make the switch, explore our Baby Shampoo & Body Wash at shopkindrednaturals.com — formulated with soapwort, fully transparent, and made for families who read the label.
Written by Mike & Carly Pronsky, founders of Kindred Naturals.