PEG-4
Reviewed by Daisy · Last updated 18 Aug 2026
Also known as: PEG
Type of polyethylene glycol | Used as a humectant and solvent in cosmetics
Addresses
EWG Safety Score
What Is PEG-4?
PEG-4 is a polyethylene glycol used as a lightweight humectant (an ingredient which attracts and holds moisture to skin) and solvent in skin care products.
The safety of PEG in its various forms has recently been questioned. The primary concern is that they can contain problematic impurities such as ethylene oxide and 1,4 dioxane. Both are by-products from the manufacturing process, not something natural to any form of PEG. Although this was once a concern, reputable cosmetic ingredient suppliers have long since eliminated these impurities from the finished ingredient, which makes PEGs safe for skin.
As for PEG-4 specifically, the independent Cosmetic Ingredient Review board has deemed it safe in its current use. The highest concentration included in cosmetics is 20%, in some manicure preparations.
Clinical Evidence & References
Published Research
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Final report on the safety assessment of Triethylene Glycol and PEG-4, International Journal of Toxicology, 25 Suppl 2:121-38, 01 Jan 2006 [https://pubmed.ncbi.nlm.nih.gov/17090481/]
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https://cosmetics.specialchem.com/inci-ingredients/peg-4 [https://cosmetics.specialchem.com/inci-ingredients/peg-4]
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PEG-4 is a variant of PEG-75, the form you will most often see on an ingredients list.
Functions as a humectant to boost skin’s hydration | May also be used as a solvent to mesh ingredients cohesively and enhance formulary texture
Related Ingredients
PEG-75
Functions as a humectant to boost skin’s hydration | May also be used as a solvent to mesh ingredients cohesively and enhance formulary texture
PEG-14
Functions as a humectant to increase skin’s hydration | May also be used as a solvent to mesh ingredients cohesively
PEG-6
A lightweight humectant and solvent that helps formulations absorb and deliver other actives
PEG-20
A versatile polymer that helps formulations blend and retain moisture
PEG-7m
A synthetic polymer that stabilises formulations and controls texture
PEG-60
A synthetic humectant and solvent that draws moisture into the skin and aids product formulation
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