Propylene Glycol Isostearate
Explained
Propylene Glycol Isostearate is the ester of propylene glycol and isostearic acid.
In formulas, it acts as an emollient that softens skin and and emulsifier that helps blend oil + water phases.
Industry survey data shows this ingredient used at 0.3-15% in current formulations.
One thing worth knowing: several propylene glycol esters, including ones structurally similar to this one, have been shown in lab studies to enhance the penetration of other active ingredients through skin. This isn't an automatic red flag, it's just a reason formulators are told to be careful pairing them with sensitive actives.
Rabbit-ear testing did give this ingredient a comedogenic rating of 3-4. Just remember finished products made with so-called comedogenic ingredients often turn out not to be comedogenic at all.
Human testing has proved that any finished product with a comedogenic ingredient won't automatically make you break out; it really comes down to concentration, formula, and your skin.
Because isostearic acid is a C18 fatty acid, this ingredient may not be fungal acne safe. The Malassezia yeast metabolizes fatty acids in the C11-24 range.
See all 24 products with Propylene Glycol Isostearate
