PCA Dimethicone
Well toleratedSiliconeskin conditioningemollientfilm-former
No meaningful concern for most people; irritation is possible but rare.
What it is
PCA dimethicone is a dimethicone chain carrying pyrrolidone carboxylic acid (PCA) groups. PCA is one of the skin's own natural moisturising factors, so this hybrid combines the smooth slip of a silicone with a small water-attracting element, and it disperses more easily in water-based formulas than plain dimethicone.
What it does well
Adds silicone smoothness with a slight hydrating character
The slip and film-forming behaviour are well established for silicones; the added benefit from the bound PCA groups at typical use levels has not been separately quantified in published clinical work.
Limited evidence
Where the EU stands
No specific restriction
No EU restriction on use or concentration in cosmetics.
