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PEG-100 Stearate

What PEG-100 Stearate is & what it does

An emulsifier almost always paired with glyceryl stearate to create stable, smooth lotions. It helps keep oil and water evenly blended and adds a light feel.

What is PEG-100 Stearate and what does it do in sunscreen?

PEG-100 Stearate is an emulsifier, the ingredient that keeps the oil and water phases of a sunscreen blended into one smooth, stable cream. It is almost always paired with glyceryl stearate, and together they give a light, even feel without separating in the tube. You will usually find it partway down the ingredient list, doing structural work rather than acting on the skin.

Is PEG-100 Stearate safe?

Yes. It is a widely used, well-tolerated emulsifier that works on the surface to hold a formula together rather than penetrating the skin. Like other PEG (ethoxylated) ingredients it can carry trace 1,4-dioxane from manufacturing, a by-product that reputable makers purify out. That is a contaminant of the process, not the ingredient itself.

Does PEG-100 Stearate clog pores?

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

Is PEG-100 Stearate fungal-acne safe?

It is a potential trigger, so people who specifically manage fungal acne may prefer to avoid it. The Malassezia yeast behind fungal acne can feed on the fatty (stearate) part of this ester, which is why it shows up on fungal-acne avoid lists. To be clear, this is one narrow skin concern, not a general safety issue: PEG-100 Stearate is harmless for everyone who does not have fungal acne.

Is PEG-100 Stearate natural or synthetic?

It is synthetic, though built from fairly natural starting materials. It joins stearic acid (a fatty acid from plant or animal sources) with ethylene oxide in a lab step called ethoxylation, which is what makes the waxy fatty acid water-dispersible. The finished emulsifier does not occur in nature.

Sunscreens with PEG-100 Stearate

We rate 1170 sunscreens that contain it, showing the top 10 by overall score:

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