Sodium Lauryl Sulfate (SLS): Why Dermatocare Recommends Avoiding It

Sodium Lauryl Sulfate (SLS) is a commonly used anionic surfactant, or in simpler terms—a detergent. It is widely incorporated in face washes, shampoos, toothpastes, and other cleansing products for its effective foaming and cleansing properties.

While the more alarming health claims about SLS—like cancer, blindness, or infertility—are not substantiated by scientific evidence, we still recommend choosing SLS-free skincare and hygiene products, especially for individuals with sensitive, allergic, or inflamed skin. Here’s why.

SLS Is a Proven Skin Irritant

SLS is widely acknowledged in dermatological literature as a primary irritant, especially at higher concentrations. Though cosmetic formulations typically use it in lower doses, daily exposure adds up—and for individuals with compromised skin, even small concentrations may be problematic as depicted by following studies:

Standard Control for Irritation Studies
SLS is commonly used as a positive control in dermatological experiments to test the irritation potential of other chemicals—because it reliably induces redness, burning, and skin barrier disruption.

Barrier Damage and Dehydration
At 10% concentration, SLS has been shown to strip away Natural Moisturizing Factors (NMFs) and impair the epidermal barrier, leading to transepidermal water loss and dry, inflamed skin.

Amplified Irritation When Combined with Other Agents
The irritant potential of SLS increases when combined with solvents like octane, toluene, cumene, or PEG compounds.

Sensitive Skin Are More Vulnerable
Individuals with rosacea, eczema, or atopic dermatitis show significantly increased SLS absorption and sensitivity, making it unsuitable for such populations.

Oxidative Stress on Skin
SLS may impair the skin’s antioxidant defense system by depleting free radical–scavenging enzymes, potentially contributing to premature aging or inflammation.

Oral Side Effects of SLS:

Toothpaste is a major source of daily SLS exposure—and absorption from the oral mucosa is far greater than from skin. Additionally, accidental ingestion increases the risk of systemic exposure.

Increased Mucosal Permeability:
SLS alters mucosal lining, making it more permeable to other potentially harmful chemicals.

Fluoride Interference:
SLS may inhibit fluoride deposition on teeth, compromising caries prevention.

Cell Damage at Low Concentrations:
Even at 0.15% concentration, SLS has shown to damage oral epithelial cells.

Mucosal Peeling and Irritation:
In controlled studies, brushing with SLS-containing toothpaste for just 4 days caused desquamation, unlike SLS-free options.

Trigger for Mouth Ulcers (Aphthous Stomatitis):
Individuals prone to frequent canker sores are advised to avoid SLS toothpaste.

Ineffective Compared to Chlorhexidine:
Despite its antibacterial claims, SLS is less effective than ingredients like chlorhexidine, and comes with higher irritation risk.

Environmental Concerns: Potential Ecotoxicity

Though direct evidence is limited, SLS is suspected to harm aquatic organisms when washed off into water bodies. Moreover, its persistence in marine ecosystems raises concerns about entry into the seafood-based food chain, which could have long-term implications for human health and biodiversity.

Myths and Facts About SLS

Does SLS Cause Cancer?

No. There is currently no scientific evidence linking SLS to cancer. It is not listed as a carcinogen by the American Cancer Society or major regulatory bodies.

Does SLS Cause Blindness?

No. While SLS can irritate the eyes, claims of it causing blindness are unfounded and lack scientific support.

Does SLS Cause Infertility?

Unproven. While some websites allege a link to infertility, no peer-reviewed human studies confirm this association.

When Should You Avoid SLS?

We recommend avoiding SLS in the following scenarios:

• If you have any dermatological condition, including eczema, psoriasis, or rosacea.
• In infant care products, as baby skin is highly permeable and sensitive.
• In leave-on products, such as moisturizers, sunscreens, toners, or serums—where prolonged exposure increases risk of irritation.
• In rinse-off products (like face wash or shampoo) if SLS appears in the first 5 ingredients, as it may indicate a concentration above the recommended 1%.
• In toothpaste, especially if you experience frequent mouth ulcers or have sensitive oral tissues.

How to Identify SLS on Labels

When checking product ingredient lists, look out for these alternate names for SLS:

• Sodium Lauryl Sulfate
• Sodium Dodecyl Sulfate
• Sulfuric Acid, Monododecyl Ester, Sodium Salt
• Sodium Salt Sulfuric Acid

Final Takeaway: Is SLS-Free Worth It?

Yes—especially for individuals with sensitive skin, allergies, skin conditions, or oral ulcers. While not inherently dangerous at regulated concentrations, the cumulative effect of daily exposure via skin and mucosa, combined with potential barrier disruption, makes SLS-free formulations a safer long-term choice.

Use Dermatocare Reviews to identify and avoid skincare products containing SLS and other potentially harmful ingredients.