Glyceryl Stearate: The Invisible Helper in Creams
Arin Editorial · how this is made
You saw 'glyceryl stearate' on a cream's ingredient list. It sounds like pure chemical, but it is one of the most common helpers in cosmetics. This ester, formed from glycerin and stearic acid, keeps water and oil together in the same formula.
What exactly is this substance?
Glyceryl stearate is an ester formed from glycerol and stearic acid. It is also called glycerol monostearate. It can be produced from vegetable oils (corn, soybean, palm kernel) or animal fats. So you can find it in both 'natural' and synthetic products.
What does it do in cosmetics?
Its best-known role is as an emulsifier: it prevents water and oil from separating, keeping the cream smooth and homogeneous. Its second role is as an emollient; it gives softness to the upper layer of the skin. It also works as a viscosity builder, opacifying agent and pearlizing agent. You can find it in many formulas, from face creams to sunscreens, cleansers and makeup products.
What do the safety data say?
In EPA's compiled data, the skin irritation test is recorded as 'no significant irritation'. The same dataset shows positive genotoxicity tests; the bacterial gene test is also positive. These results measure different things: one looks at the effect of skin contact, the other looks at genetic material under laboratory conditions. A positive result points to a potential hazard; but without combining dose, species and route of exposure, you cannot say it is harmful in this product.
Current regulatory data available do not show a ban or usage restriction for this ingredient.
Seeing glyceryl stearate on a label does not require any special action on its own. This ingredient is a routine emulsifier in cosmetics. Still, when you first use a new product, trying it on a small area is always a good habit.
Sources
- U.S. EPA ToxValDB (CAS 31566-31-1)