INCI: Sodium Lauryl Sulfate
Anionic surfactant with strong cleansing properties. Effectively removes oil but aggressively disrupts the lipid barrier. The standard irritant in dermatological patch testing.
Topical application
DVery weak or conflicting data.
A surfactant, not an active ingredient. CIR deemed safe in rinse-off products. In leave-on formulas at concentrations above 1%, it irritates skin. True SLS contact allergy is extremely rare – irritation is commonly mistaken for allergy.
Sodium Lauryl Sulfate (SLS) is an anionic surfactant with a short, harsh cleansing chain (C12). INCI: Sodium Lauryl Sulfate. Produced by esterifying lauryl alcohol with sulfuric acid and neutralizing with sodium. Main function is strong cleansing and foam. Used in toothpastes, shampoos, body washes, and cleansing masks. Typical use concentration is 0.5% (toothpaste) to 10% (concentrated shampoos). Pregnancy safety. SLS is considered safe during pregnancy. Systemic absorption through intact skin is minimal, exposure is brief in rinse-off products. Use in toothpaste and shampoo during pregnancy is unrestricted. Skin safety. A harsh surfactant with high irritation potential. SLS strips lipids from the skin, disrupts the keratin barrier with prolonged contact, and can cause dryness and flaking. SLS is used as a standard irritant in patch testing – mildness of other surfactants is benchmarked against it. Important nuance. Irritation scales with concentration and contact time. In rinse-off products (body washes, shampoos) at 1–3% SLS, irritation is uncommon in people with a healthy barrier. People with atopic dermatitis, eczema, or a damaged barrier should avoid SLS. In toothpaste. SLS in toothpaste is associated with more frequent aphthous stomatitis in predisposed individuals. People with recurrent aphthae do better on SLS-free pastes. Compared with SLES and cocamidopropyl betaine. Sodium Laureth Sulfate (SLES) is an ethoxylated form of SLS and noticeably milder. Cocamidopropyl betaine is a mild amphoteric surfactant, often combined with SLS to reduce total irritation. Non-comedogenic. SLS does not clog pores but can indirectly worsen acne through irritation and barrier disruption. Bottom line. SLS is effective but harsh. Safe during pregnancy and lactation, but people with sensitive skin, atopy, or recurrent aphthae should choose milder alternatives.
Irritation potential
HighAllergen risk
LowPregnancy
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Sodium Lauryl Sulfate (SLS) is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
Sodium Lauryl Sulfate (SLS) suits: oily. Use with caution in: sensitive, dry, combination.
Yes, Sodium Lauryl Sulfate (SLS) has high irritation potential. Start at low concentrations, introduce gradually, and always use SPF during the day.
Anionic surfactant with strong cleansing properties.
The INCI name is Sodium Lauryl Sulfate. It may also appear as: SLS.
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For sensitive skin
SLS is used as the reference irritant in patch testing. For sensitive skin, eczema, and rosacea, choose gentler surfactants (coco-glucoside, lauryl glucoside).
Suitable for
Use with caution