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Steareth-20

What Steareth-20 is & what it does

A nonionic emulsifier made by attaching about 20 units of ethylene oxide to stearyl alcohol, a fatty alcohol. It blends the oil and water phases of a cream into one stable, smooth mixture and is often paired with steareth-2 to fine-tune the texture. It works on the surface of the formula, keeping oil and water evenly mixed rather than acting on the skin itself.

What is Steareth-20 and what does it do in sunscreen?

Steareth-20 is a nonionic emulsifier. It blends the oil and water phases of a sunscreen into one stable, smooth lotion and stops them separating. It is made by attaching about 20 units of ethylene oxide to stearyl alcohol, a fatty alcohol, and is frequently paired with the more oil-loving steareth-2 to balance the emulsion. The 20 refers to the units of ethylene oxide, not a percentage.

Is Steareth-20 safe?

Yes. It is a widely used, well-tolerated emulsifier reviewed as safe in cosmetics. Like other 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 levels used in sunscreen it is non-irritating for most people.

Does Steareth-20 clog pores?

Generally no. It is treated as low on the comedogenicity scale and is not one of the classic pore-clogging ingredients. It is an emulsifier used in small amounts rather than a heavy oil or wax. If a product is breaking you out, the richer emollients and oils elsewhere in the formula are far more likely the cause.

Is Steareth-20 fungal-acne safe?

For most people it is fine, but if you are fungal-acne prone you may prefer to avoid it. Steareth-20 is built on a fatty (stearyl) part that the malassezia yeast behind fungal acne can potentially use, which is why it appears on feeder lists. This is one specific skin concern, not a general safety issue, so it only matters if fungal acne is something you personally deal with.

Is Steareth-20 natural?

No, it is synthetic. It starts from stearyl alcohol, which is often plant-derived, but it is then ethoxylated in the lab, a man-made step. The finished emulsifier does not occur in nature, and that is fine for the job it does.

Sunscreens with Steareth-20

We rate 122 sunscreens that contain it, showing the top 10 by overall score:

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