Why Should You Avoid SLS (Sodium Lauryl Sulfate) In Toothpaste?

Many of us have experienced the discomfort of a dry mouth, increased sensitivity, or even painful ulcers—but few people consider their toothpaste as the cause. While brushing should leave your mouth feeling fresh and clean, a common ingredient in conventional toothpaste, Sodium Lauryl Sulfate (SLS), may be doing more harm than good.

SLS is a foaming agent found in many household products, from shampoos to detergents, but its use in toothpaste raises serious concerns. Studies have linked it to dry mouth (xerostomia), mouth ulcers, tissue irritation, and even a disrupted oral microbiome. If you’ve ever felt a stinging sensation after brushing, struggled with recurring canker sores, or noticed your mouth feeling parched, your toothpaste could be to blame.

Let’s explore why SLS is problematic, how it affects your oral health, and why switching to an SLS-free toothpaste like Duo Toothpaste can transform your brushing routine.

What Is SLS? A Common Yet Controversial Ingredient

Sodium Lauryl Sulfate is a synthetic surfactant and detergent used in many cleaning and personal care products due to its ability to create a rich, foamy lather. While it helps toothpaste spread and removes debris, its harsh cleansing action can damage the delicate tissues inside your mouth.

SLS is derived from coconut oil or petroleum and is classified as an anionic surfactant, meaning it lowers surface tension to trap oil, grease, and dirt. This makes it an effective cleaning agent in products like:

• Household cleaners
• Shampoos
• Body washes
• Dish soaps
• Toothpastes

However, just because SLS cleans effectively doesn’t mean it belongs in your mouth.

The Science: How SLS Harms Oral Health

SLS has been shown to:

1. Cause Dry Mouth by Disrupting Saliva Production

Saliva is essential for maintaining a healthy mouth—it neutralizes acids, washes away bacteria, and aids in digestion. However, SLS has been found to disrupt the delicate balance of saliva production, leading to xerostomia (dry mouth).

A study published in the International Journal of Molecular Sciences found that SLS exposure damages the mucosal lining in the mouth, reducing moisture and increasing susceptibility to bacterial overgrowth. This is especially problematic because a dry mouth:

• Increases the risk of cavities and gum disease
• Causes bad breath (halitosis)
• Leads to discomfort and difficulty swallowing

If you frequently wake up with a dry mouth or experience excessive thirst, your toothpaste could be a contributing factor.

2. Trigger Canker Sores and Oral Ulcers

SLS has been directly linked to recurrent aphthous stomatitis (canker sores). These painful ulcers form inside the mouth and can take up to two weeks to heal.

A clinical study published in Acta Odontologica Scandinavica compared individuals using SLS-containing toothpaste to those using SLS-free toothpaste. The results were striking:

• People using SLS toothpaste had a 60% higher recurrence of canker sores
• The sores were larger and more painful
• Switching to SLS-free toothpaste significantly reduced the frequency and severity of ulcers

This happens because SLS strips away the protective mucosal layer inside your mouth, leaving it vulnerable to irritation.

3. Disrupt the Oral Microbiome

Your mouth is home to a delicate ecosystem of bacteria—some harmful, but many beneficial. Maintaining a balanced oral microbiome is essential for:

• Preventing cavities and gum disease
• Supporting digestion
• Strengthening the immune system

However, SLS has been shown to act as a broad-spectrum antimicrobial, meaning it kills both harmful and beneficial bacteria. A disrupted microbiome can lead to:

• Increased cavity formation
• Inflammation and gum sensitivity
• Higher susceptibility to infections

4. Cause Tissue Irritation and Peeling

Many people who use SLS toothpaste notice that the inside of their cheeks peel after brushing. This occurs because SLS damages oral tissues, leading to redness, irritation, and inflammation.

A study in the Journal of Clinical Periodontology found that patients using SLS-containing toothpaste reported more cases of gum irritation and oral discomfort compared to those using an SLS-free alternative.

Perspective of a Dentist

Dr. Stevie Roberts, a general dentist, explains:

"Choosing toothpaste without harsh surfactants like SLS can significantly reduce oral irritations, especially for patients prone to dry mouth or ulcers. SLS-free formulas help preserve the delicate balance of the oral microbiome, promoting better long-term oral health."

Duo Toothpaste: The Gentle, Effective Alternative

At Duo Toothpaste, we believe your toothpaste should work with your body, not against it. That’s why we’ve formulated an SLS-free toothpaste that provides superior oral health benefits without irritation.

Why Choose Duo Toothpaste?

✔ SLS-Free & Non-Irritating: No harsh surfactants, just a gentle clean.
✔ Nano-Hydroxyapatite (nHA): Clinically proven to remineralize enamel and reduce sensitivity.
✔ Fluoride-Free Formula: A natural, effective alternative to fluoride.
✔ Supports a Healthy Oral Microbiome: No disruption to beneficial bacteria.
✔ Eco-Friendly & Plastic-Free: Sustainable packaging for a greener planet.

Make the switch today and experience the difference with Duo. Learn more here.