CosmeticBet
Cleansers

Sodium lauryl sulfate

INCI: SODIUM LAURYL SULFATE · also SLS

A strong cleanser, and science’s standard skin irritant.

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C12H25NaO4S288.38 g/mol
sulfursodiumoxygencarbon
2D drawing from PubChem 3423265 (hydrogens hidden)

How common

All products6.4%
In toothpastes44%
In shampoos14%
In conditioners6.7%

947 of 14,784 products with a full ingredient list in Open Beauty Facts; No. 46 of all the names found on their labels.

What it is

  • A strong cleanser (an anionic surfactant).

    2 sourcesHide
    sodium lauryl sulfate[1] Study · 2015 · open source
    anionic surfactants are strong cleaners[1] Study · 2015 · open source

Why it is in products

  • It cleans very well, foams richly, rinses easily, and works in hard or soft water. It is common in shampoos for oily hair.

    SourceHide
    Lauryl sulfates: Popular primary cleansers, they work well in both hard and soft water, produce rich foam, and are easily rinsed. They are excellent cleansers, commonly used in shampoos for oily hair.[2] Study · 2015 · open source

Downsides and safety

  • It is the standard irritant of skin research: scientists use it to damage the skin barrier on purpose in tests.

    Well established2 sourcesHide
    the standard irritant sodium lauryl sulfate (SLS)[3] Study · 2003 · open source
    a barrier damage due to a repeated washing with sodium lauryl sulphate[4] Study · 1999 · open source

  • Far harsher than its relative SLES: in a patch-test study, SLS caused a pronounced reaction and SLES a far milder one.

    Good evidenceSourceHide
    We found a pronounced reaction to SLS, and a far milder one to SLES.[3] Study · 2003 · open source

  • It can leave hair harsh and rough, so shampoos pair it with a second, milder cleanser and conditioning agents.

    Some evidencehairSourceHide
    As the hair becomes harsh and rough, careful selection of a secondary detergent and possible use of a conditioning agent is always required as part of the shampoo formulation.[2] Study · 2015 · open source

Where it works

Surface (cuticle)Inside (cortex)Core (medulla)

On the surface of hair and scalp, where it removes oil (sebum).

SourceHide
they are very good at removing sebum from the scalp and hair[2] Study · 2015 · open source

Rules

European Union

  • No EU limit: it is not on the regulation’s lists of banned or restricted substances, preservatives or UV filters.

    How we checkedHide
    We searched Annexes II to VI of the EU regulation (consolidated text of 18 May 2026): no entry.open the list

United States

  • Not on the FDA’s list of prohibited or restricted cosmetic ingredients. In the US, cosmetics and their ingredients (other than colour additives) don’t need FDA approval before sale.

    SourceHide
    Under U.S. law, cosmetic products and ingredients, other than color additives, do not need FDA approval before they go on the market[5] US Food and Drug Administration · open source
    We searched the FDA’s list of prohibited and restricted cosmetic ingredients: no entry.open the list

Sources

  1. Hair Cosmetics: An Overview International Journal of Trichology, 2015Study
  2. Shampoo and Conditioners: What a Dermatologist Should Know? Indian Journal of Dermatology, 2015Study
  3. Profile of irritant patch testing with detergents: sodium lauryl sulfate, sodium laureth sulfate and alkyl polyglucoside Löffler H et al., Contact dermatitis, 2003Study
  4. Glycerol accelerates recovery of barrier function in vivo Fluhr JW et al., Acta dermato-venereologica, 1999Study
  5. Prohibited & Restricted Ingredients in Cosmetics | FDA US Food and Drug Administration

Checked against these sources on 4 November 2026. Spot a mistake? Tell us.