SLS in Toothpaste: What Does the Research Say – and Should You Switch?

When choosing a toothpaste, most people focus on flavour, freshness or whitening. But one common ingredient often goes unnoticed: Sodium Lauryl Sulfate (SLS).

SLS is added to many toothpastes to create foam. While this foaming action can make brushing feel more effective, research suggests it may not always be the best choice for everyone — particularly those with sensitive mouths.

At Oswyn House Dental Practice, we believe in evidence-based dentistry. Here’s what the research tells us about SLS, and why some patients may benefit from switching to an SLS-free toothpaste.

What Is SLS and Why Is It Used?

Sodium Lauryl Sulfate is a detergent. Its role in toothpaste is to:

• Create foam.

• Help spread toothpaste around the mouth.

• Lift debris from tooth surfaces.

Importantly, SLS itself does not prevent tooth decay or gum disease. Its role is mainly cosmetic and functional rather than therapeutic.

What Does the Research Show?

1. Plaque and Gum Health

Randomised controlled trials comparing SLS-containing and SLS-free toothpastes have shown:

• No significant difference in plaque levels.

• No significant difference in gingivitis or gum bleeding.

In simple terms, SLS is not essential for effective cleaning.

2. Mouth Ulcers (Canker Sores)

This is where the strongest evidence lies.

Systematic reviews of randomised controlled trials have shown that people prone to recurrent aphthous ulcers (canker sores) experienced:

• Fewer ulcers.

• Shorter ulcer duration.

• Less pain.

when using SLS-free toothpaste compared to standard toothpaste.

For patients who regularly suffer from mouth ulcers, switching to an SLS-free toothpaste is a clinically supported recommendation.

3. Oral Irritation and Sensitivity

RCTs and controlled studies also suggest that SLS can:

• Increase oral mucosal irritation in some individuals.

• Contribute to dryness or a burning sensation.

This is particularly relevant for patients with:

• Sensitive oral tissues.

• Dry mouth.

• Orthodontic appliances.

• Dental implants.

Who May Benefit from an SLS-Free Toothpaste?

You may wish to consider an SLS-free toothpaste if you:

• Frequently get mouth ulcers.

• Experience stinging or soreness when brushing.

• Have sensitive gums or dry mouth.

• Prefer a gentler oral care routine.

For many patients, this small change can make a noticeable difference.

Our Recommended SLS-Free Toothpaste: Curaprox Enzycal

One toothpaste we regularly recommend at Oswyn House Dental Practice is:

Curaprox Enzycal Toothpaste

Why we like it:

• SLS-free, reducing irritation to the oral tissues.

• Uses natural enzymes to support saliva’s protective function.

• Low abrasivity, protecting enamel and gums.

• Suitable for sensitive mouths, braces and implants.

• Compatible with medicated mouthwashes.

Curaprox Enzycal cleans effectively without relying on harsh detergents, making it an excellent everyday option for patients looking for a gentler alternative.

Will an SLS-Free Toothpaste Still Protect My Teeth?

Yes — provided it contains fluoride (or appropriate alternatives where indicated).

The most important factors for decay prevention remain:

• Fluoride exposure.

• Effective brushing technique.

• Consistency (twice daily brushing).

• Regular dental check-ups.

Foam is not a marker of effectiveness.

The Bottom Line

• SLS is not harmful for everyone, but it is also not essential.

• High-quality research shows no added benefit for plaque or gum health.

• Strong evidence supports SLS-free toothpaste for patients with recurrent mouth ulcers.

• Many people find SLS-free options more comfortable and better tolerated.

If you’ve struggled with irritation, sensitivity or mouth ulcers, switching toothpaste is a simple, low-risk step that may help.

Need Personalised Advice?

If you’re unsure which toothpaste is right for you, our team at Oswyn House Dental Practice will be happy to advise you based on your individual needs.

Contact us or ask at your next appointment — we’re always happy to help!