PEG-4 is a low-molecular-weight polyethylene glycol used in skincare as a humectant, solvent, and emollient base ingredient that improves texture and helps dissolve other components. It functions primarily as a formulation aid rather than an active treatment ingredient.
| Reported effect | How often | Notes |
|---|---|---|
Mild skin irritation | Uncommon | Possible in sensitive individuals, especially on broken or compromised skin. |
Contact dermatitis / allergic sensitization | Rare | Documented in patch-test literature, more often on damaged skin or with higher concentrations. |
Increased penetration of other ingredients | Uncommon | PEGs can enhance absorption of co-formulated substances, which may amplify their effects. |
Systemic toxicity from impurities | Very rare | Concern relates to potential ethylene oxide/1,4-dioxane residues from manufacturing, not PEG-4 itself; minimized by purification. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.