In the world of surfactant chemistry, ethoxylation is a chemical process where ethylene oxide, a highly reactive three-membered ring molecule, is added to a base ingredient, typically an alcohol. Ethoxylation can also be part of the process to make a wide variety of chemical intermediates and additives like Isethionic Acid and Triethanolamine.

The starting alcohols can come from natural sources like coconut or palm kernel oil, or they can be synthetically derived from petrochemicals. Depending on how much ethylene oxide gets added, you end up with ingredients that have very different properties—some dissolve better in water (high HLB), others in oil (low HLB).

The Workhorse Ingredients

Ethoxylated ingredients have been industry favorites for decades because they’re incredibly versatile:

Steareth-2 and Steareth-20: The classic oil-in-water emulsifier combination that keeps your lotions stable
Polysorbates: Another go-to emulsifier family
PEG-40 Hydrogenated Castor Oil: The fragrance industry’s favorite solubilizer—helps those lovely scents blend into water-based products
Sodium Laureth Sulfate (SLES): A gentler cousin of SLS, this cleansing surfactant creates abundant lather in shampoos
PEG-150 Distearate: A thickening agent that helps keep cleansing formulations from running through your fingers
PEG-7 Glyceryl Cocoate: Adds that moisturizing, “refatting” feel to rinse-off products

Why They’ve Been So Popular

The beauty of ethoxylation is customization. By varying the amount of ethylene oxide added, chemists can fine-tune ingredients for specific jobs like making them more water-soluble, less irritating, or better at foaming. This flexibility made ethoxylates the foundation of modern personal care formulation.

However, there’s a catch. During the ethoxylation process, a byproduct called 1,4-dioxane can form—and that’s raising some serious concerns we’ll explore in our next post.