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PEG-40 Stearate

What PEG-40 Stearate is & what it does

An emulsifier and solubilizer that disperses oils into water phases and stabilizes lotions. It gives a smooth, light feel.

What is PEG-40 Stearate and what does it do in sunscreen?

PEG-40 Stearate is an emulsifier and solubilizer. It disperses oils into the water phase of a sunscreen and helps stabilize the finished lotion, giving a smooth, light feel. It is made by joining stearic acid, a fatty acid, with polyethylene glycol, where the 40 refers to the units of ethylene oxide rather than a percentage. It works on the formula rather than on the skin.

Is PEG-40 Stearate safe?

Yes. It is a widely used, well-tolerated emulsifier considered safe in cosmetics. Like other PEG (ethoxylated) ingredients it can carry trace 1,4-dioxane from manufacturing, which reputable makers purify out. That is a contaminant, not the ingredient itself, and at the small amounts used in sunscreen it is non-irritating for most people.

Does PEG-40 Stearate clog pores?

Generally no. It is treated as low on the comedogenicity scale and is not a classic pore-clogging ingredient. It is a lightweight emulsifier and solubilizer used in small amounts, not a heavy oil or wax. If you are breaking out, the richer emollients and oils elsewhere in a formula are the more likely cause.

Is PEG-40 Stearate fungal-acne safe?

For most people it is fine, but those who are fungal-acne prone may prefer to avoid it. PEG-40 Stearate carries a fatty (stearic) part that the malassezia yeast behind fungal acne can potentially use, which is why it shows up on feeder lists. This is one specific skin concern rather than a general safety issue, so it is only worth avoiding if you react to fungal-acne triggers.

Is PEG-40 Stearate natural?

No, it is synthetic. The stearic acid side is often plant-derived, but it is joined to polyethylene glycol in the lab, a man-made step. The finished emulsifier does not occur in nature, so PEG-free formulas usually swap it for polyglyceryl-based emulsifiers instead.

Sunscreens with PEG-40 Stearate

We rate 110 sunscreens that contain it, showing the top 10 by overall score:

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