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METHOXY PEG-40

CAS 9004-74-4
84

Safety score · 0–100

Good

Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.

About

A water-soluble polymer that acts like a glycerin twin with a longer chain — draws moisture to the skin and keeps formulations feeling smooth and slightly thick.

Methoxy PEG-40 is a methyl-capped polyethylene glycol with an average of 40 ethylene oxide units (nominal formula CH3O-(CH2CH2O)40-H). The methyl terminus reduces polarity slightly compared to unterminated PEG, improving skin-feel. It functions as a humectant and skin-conditioning agent. PEG polymers of this size are not significantly absorbed through intact skin and have a well-established safety record in cosmetics.

Skin benefits

  • Strong humectant — attracts and retains water
  • Conditions and smooths skin
  • Improves product texture

Known concerns

  • May increase absorption of other ingredients through damaged skin
  • PEG contamination concerns (ethylene oxide, 1,4-dioxane) in low-purity grades

References

EU

EU CosIng database

European Commission cosmetic ingredient registry — regulatory status, restrictions, authorised functions.

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This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve — always read the physical product label and consult a healthcare professional for personal concerns.