PEG-33 at a glance

  • Lightweight, skin-friendly polymer
  • Helps draw and hold moisture within skin
  • Enhances formulary stability
  • Works as a non-irritating solvent

PEG-33 description

PEG-33 is the synthetic polymer of ethylene oxide used as a binding agent and humectant. With any PEG (polyethylene glycol) ingredient followed by a number, the lower the number, the lighter the ingredient. Thus, PEG-33 will feel lighter on skin than PEG-200. Among many other PEG-based ingredients, PEG-33 is considered safe as currently used in a broad range of rinse-off and leave-on cosmetics.

PEG-33 references

  • Toxicological Research, June 2015, pages 105–136
  • International Journal of Toxicology, November 2014, pages 13S–39S; and International Journal of Toxicology, May 1997, pages 269–300

Peer-reviewed, substantiated scientific research is used to assess ingredients in this dictionary. Regulations regarding constraints, permitted concentration levels and availability vary by country and region.

Ingredient ratings


Proven and supported by independent studies. Outstanding active ingredient for most skin types or concerns.


Necessary to improve a formula's texture, stability, or penetration.


Generally non-irritating but may have aesthetic, stability, or other issues that limit its usefulness.


There is a likelihood of irritation. Risk increases when combined with other problematic ingredients.


May cause irritation, inflammation, dryness, etc. May offer benefit in some capability but overall, proven to do more harm than good.


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Not Rated