A powerful anionic surfactant found in 1,110 products in our database. CIR rated it "Safe with Qualifications" — meaning it is considered safe when used in rinse-off formulations designed for brief skin contact at appropriate concentrations. SLS has strong cleansing power and is one of the most widely studied surfactants, but its well-documented skin irritation potential at higher concentrations makes it a polarising ingredient.
Sodium Lauryl Sulfate (SLS) is an anionic surfactant — a cleansing agent that lowers the surface tension between oil and water, allowing dirt, sebum, and makeup to be washed away. It is a widely used surfactant with strong cleansing power in personal care, found in cleansers, shampoos, body washes, and toothpaste. SLS produces a rich, satisfying foam that many consumers associate with thorough cleaning.
Chemically, SLS (also known as Sodium Dodecyl Sulfate or SDS) is the sodium salt of lauryl sulfuric acid, with the molecular formula CH₃(CH₂)₁₁OSO₃Na. It is typically derived from lauryl alcohol, which can be obtained from coconut or palm kernel oil, followed by sulfation and neutralisation. Despite sometimes being marketed as "natural" due to its plant-derived precursor, SLS undergoes significant chemical processing. It is a white or cream-coloured powder or crystal that is highly soluble in water.
SLS has been used in cosmetics and personal care products for decades and is one of the most extensively studied surfactants. CIR (Cosmetic Ingredient Review) evaluated SLS and rated it "Safe with Qualifications." The key qualifications are that products containing SLS should be formulated to minimise irritation — primarily by using SLS in rinse-off products with brief skin contact, keeping concentrations as low as practical, and avoiding prolonged or occlusive exposure. SLS is not restricted under the EU Cosmetics Regulation and has no maximum concentration limit, but responsible formulation practice acknowledges its dose-dependent irritation potential.
SLS has strong degreasing and cleansing ability, efficiently removing sebum, dirt, and oil from skin and hair. Its strong degreasing ability makes it particularly effective in shampoos for oily hair and facial cleansers for oily or acne-prone skin.
Produces abundant, dense foam that consumers associate with effective cleansing. While foam itself does not determine cleaning power, it helps distribute the product evenly across skin and hair, improving the wash experience.
As an emulsifier, SLS helps oil-based and water-based ingredients stay mixed in formulations. This is critical for cleansing products that need to lift oily residue and suspend it in water for rinsing.
SLS is inexpensive to produce and has decades of safety data behind it. Its behaviour is well-understood by formulators, making it a reliable choice when formulating within appropriate concentration and use parameters.
Best suited for: Normal to oily skin, in rinse-off products with brief contact time. Not recommended for sensitive, dry, or eczema-prone skin — milder surfactant alternatives (Coco-Glucoside, Sodium Cocoyl Isethionate) are preferable for these skin types.
SLS is a well-documented skin irritant whose risk depends heavily on concentration, contact time, and individual skin sensitivity. CIR rated it "Safe with Qualifications" — safe in rinse-off products at appropriate concentrations with brief skin contact, but not recommended for prolonged exposure or leave-on use. No dedicated SCCS opinion exists for SLS. Our medium risk rating reflects the genuine irritation potential balanced against the established safety in properly formulated rinse-off products.
SLS has no EU harmonised classification in CLP Annex VI. All hazard codes below are self-classifications reported by REACH registrants and CLP notifiers — individual companies' own assessments, not an official EU regulatory determination:
H302 — Harmful if swallowed H310 — Fatal in contact with skin H311 — Toxic in contact with skin H312 — Harmful in contact with skin H315 — Causes skin irritation H318 — Causes serious eye damage H319 — Causes serious eye irritation H332 — Harmful if inhaled H335 — Respiratory irritation H370 — Causes damage to organs H373 — May cause damage to organs (prolonged) H400 — Very toxic to aquatic life H412 — Harmful to aquatic life (long lasting)
Important context: The large number of hazard codes reflects the wide range of self-classifications from different suppliers and registrants. Variations arise because different companies test different grades of SLS (varying purity, physical form, and concentration) under different conditions. Some severe codes (H310, H370) appear in only a small number of notifications and may reflect specific test conditions or impurities, while others (H315, H319) are more consistently reported. Because there is no EU harmonised classification for SLS, there is no single official regulatory determination of its hazard profile for the raw material.
Raw material hazard ≠ product risk: These classifications describe the pure substance. In cosmetic products, SLS is used at much lower concentrations in formulations designed to minimise irritation (typically rinse-off products with brief skin contact). The risk profile of SLS in a properly formulated cleanser is fundamentally different from the pure powder.
Dose-dependent irritation. SLS irritation potential increases with concentration and contact time. At typical rinse-off concentrations (1–5%) with brief contact (<1 minute), most people can tolerate it, though mild dryness or tightness may still occur. Higher concentrations, prolonged exposure, or use under occlusion significantly increase irritation risk. This is why SLS is best suited for rinse-off products.
Barrier disruption. SLS can strip natural lipids from the skin's surface and temporarily disrupt the skin barrier. For people with already compromised barriers (eczema, rosacea, very dry skin), this can exacerbate dryness, redness, and sensitivity. Milder surfactants are a better choice for these skin types.
Primarily an irritant, not a sensitiser. SLS reactions are overwhelmingly irritant contact dermatitis (ICD) — a direct chemical effect on the skin, not an immune-mediated response. True allergic contact dermatitis (ACD) to SLS is rare but has been reported in isolated cases. This distinction matters clinically: ICD resolves immediately upon discontinuation, while ACD involves immune memory and may recur on re-exposure.
SLS does not have specific reproductive or developmental toxicity concerns at cosmetic use levels. It is a topical surfactant used in rinse-off products with minimal systemic absorption. There are no regulatory warnings regarding SLS use during pregnancy or nursing. The primary concern during pregnancy — as at any other time — is skin irritation, which may be heightened during pregnancy due to hormonal skin changes. If your skin becomes more sensitive during pregnancy, consider switching to a milder surfactant rather than specifically avoiding SLS. Consult your healthcare provider if you have concerns.
SLS is best suited for rinse-off products. When using an SLS-containing cleanser or shampoo, apply, lather briefly (30–60 seconds), and rinse thoroughly. Avoid leaving SLS products on your skin longer than necessary. The shorter the contact time, the less opportunity for irritation.
Ensure all product residue is completely rinsed away. SLS residue left on the skin continues to interact with the skin barrier. Pay particular attention to the hairline, jawline, and neck when using SLS shampoos, as residue in these areas can cause breakouts or irritation.
Because SLS can temporarily strip natural skin oils, apply a moisturiser or conditioner after cleansing to restore hydration and support the skin barrier. This is especially important if you use SLS-containing products daily.
Brief application, massage, and rinse. Best for oily skin. Consider milder surfactants if you have dry or sensitive skin.
Effective at removing oil and product build-up. SLS shampoos may be too stripping for colour-treated or dry hair.
Used as a foaming agent. If you experience recurrent mouth ulcers, try switching to an SLS-free toothpaste.
An amphoteric surfactant commonly paired with SLS to reduce irritation potential. The combination provides good foam and cleansing while being gentler than SLS alone.
Formulators add humectants like Glycerin or Panthenol to SLS-based cleansers to offset the degreasing effect and reduce post-wash tightness. Look for these in the ingredient list.
Following SLS cleansing with Hyaluronic Acid serums, Ceramide creams, or Niacinamide moisturisers helps restore the skin barrier and counteract any temporary dryness.
Using SLS cleansers alongside Retinol, AHA, or BHA can compound irritation and barrier disruption. If you use active exfoliants, consider a gentler cleanser to avoid over-stripping your skin.
Combining SLS with other harsh surfactants (Ammonium Lauryl Sulfate, Sodium C14-16 Olefin Sulfonate) intensifies the stripping effect. Well-formulated products balance harsh and mild surfactants.
SLS should not be used in leave-on formulations (moisturisers, serums, masks that remain on skin). Prolonged contact significantly increases irritation risk. SLS belongs in rinse-off products only.
Found in 1,110 products in our database — commonly used in cleansers, shampoos, body washes, and toothpaste. Here are some examples:
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