Ingredient dictionary

PEG-40 Stearate

Also listed as: Polyoxyl 40 Stearate

A mild emulsifier made from polyethylene glycol and stearic acid, a plant or animal fat. Its main job is helping oil and water blend smoothly. It is on the label of 8 products in our library. Checked against our library November 6, 2026.

What PEG-40 Stearate does

Blends oil and water into one mix
Keeps creams and lotions from separating
Gives formulas a smooth, even feel

PEG-40 Stearate is made by joining many small units of ethylene oxide into a chain, called polyethylene glycol, and attaching that chain to stearic acid. The 40 refers to the average number of repeating units in the chain. Stearic acid is a common fatty acid found in plant and animal fats, so it is familiar to formulators.

Formulators use it because oil and water do not mix on their own. PEG-40 Stearate sits at the boundary between them, so droplets of one stay evenly spread through the other. This helps creams and lotions stay smooth and keeps them from separating. It also appears in cleansers and sunscreens, where it helps give a light, even texture.

Good for

Suits most skin types, since it is a common, well-tolerated ingredient in creams, lotions, cleansers and sunscreens.

Frequently asked questions

Is PEG-40 Stearate safe for sensitive skin?

It is widely used in creams and lotions and is generally well tolerated. Anyone with reactive skin can still react to it, so a patch test on a small area is a sensible first step. Stop using the product if redness or itching appears.

What does PEG mean on a label?

PEG stands for polyethylene glycol, a water-soluble chain of repeating units. The number after it shows how many units are in the chain. Many PEG ingredients act as emulsifiers, thickeners or softeners in creams and lotions.