Friday, Jul 24, 2026 The claims desk. Receipts included. POWERED BY LENZ
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SCIENCE

The Claim

Most shampoos are primarily composed of five ingredient categories: water (as a solvent), surfactants such as sodium lauryl sulfate (SLS) or sodium laureth sulfate (SLES), conditioning agents such as silicones or quaternary ammonium compounds (quats), preservatives such as sodium benzoate, and fragrances or colorants.

The Short Version

The claim captures the main functional backbone of many shampoo formulas. Technical references consistently describe shampoos as water-based systems built around surfactants, conditioning materials, preservatives, and aesthetic additives. However, it simplifies formulation practice by leaving out other routine categories such as co-surfactants, thickeners, and pH adjusters, and sodium benzoate is only one of several common preservative choices.

Caveats

  • The list is not exhaustive: many shampoos also include co-surfactants, viscosity modifiers, pH adjusters, opacifiers, and chelating agents.
  • Sodium benzoate is a legitimate preservative example, but mainstream shampoos also commonly use other preservative systems.
  • Not every shampoo contains all listed examples; sulfate-free, fragrance-free, colorant-free, and low-conditioning formulas are common variants.

The Receipts

  1. ANNEX V – List of preservatives allowed in cosmetic products

    European Commission (CosIng / Cosmetics Regulation Annex V)

  2. Sodium benzoate

    PubChem (NIH)

  3. Overview of preservatives used in cosmetics

    PubMed

  4. Shampoo: More Than Just Hair Cleanser

    Gastronomica (University of California Press)

  5. Shampoos: Their Composition and Function

    PubMed Central

  6. Shampoos: ingredient base and formulation

    PubMed

  7. Formulation of Shampoos (chapter in Conditioning Agents for Hair and Skin)

    ScienceDirect (Woodhead Publishing)

  8. Formulation of Shampoos (chapter in a cosmetic science text)

    Wiley Online Library

  9. Shampoo and conditioning agents

    PubMed

  10. Shampoo compositions and methods of use

    Google Patents

+ 22 more sources — see the full list on Lenz

Filed Under

Sodium BenzoateSodium Laureth SulfateSodium Lauryl Sulfate