What it is
This ingredient is made by reacting hydrogenated castor oil with roughly 100 units of ethylene oxide, producing a water-dispersible nonionic surfactant. In sunscreens and creams it helps emulsify oils into water, stabilize the emulsion, and solubilize oil-soluble components such as fragrances or oil-soluble UV filters. It is a common processing aid that contributes to a smooth, uniform texture.
Safety & warnings
PEG castor oil derivatives are widely used and generally well tolerated in cosmetics. As with other ethoxylated ingredients, the manufacturing process must control residual ethylene oxide and 1,4-dioxane; reputable suppliers purify to low residual levels. It is not considered a notable comedogen at typical use levels, and contact sensitization is uncommon.
Origin & sourcing
Semi-synthetic; derived from castor oil (from the seeds of Ricinus communis), which is hydrogenated and then ethoxylated with ethylene oxide.
Questions everyone asks
What is the role of PEG-100 Hydrogenated Castor Oil?
It acts as a nonionic emulsifier and solubilizer, helping blend oil and water phases and dissolve oil-soluble ingredients into the formula.
Is it derived from a natural source?
It starts from castor oil, a plant oil, which is then hydrogenated and chemically modified with ethylene oxide, so it is best described as semi-synthetic.