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Trimethylsiloxysilicate

What Trimethylsiloxysilicate is & what it does

A silicone resin that forms a durable, water-resistant film, boosting the staying power and transfer resistance of long-wear formulas. It helps sunscreens resist sweat and water.

What is Trimethylsiloxysilicate and what does it do in sunscreen?

Trimethylsiloxysilicate is a silicone resin that forms a durable, water-resistant film on the skin. In a sunscreen it boosts staying power and transfer resistance, which is why it shows up so often in long-wear and tinted formulas. The film it leaves helps the product resist sweat and water and keeps it from rubbing off too quickly.

Is Trimethylsiloxysilicate safe?

Yes. Silicone resins like Trimethylsiloxysilicate are inert, sit on the surface of the skin, and are not absorbed in any meaningful way. They have a long record of safe, well-tolerated use in cosmetics, including long-wear makeup and sunscreens. For most people it is non-irritating and non-sensitizing.

Does Trimethylsiloxysilicate clog pores?

Generally no. Trimethylsiloxysilicate is a film-forming silicone rather than an oil or wax, and silicones of this type are usually treated as low on the comedogenicity scale. It forms a breathable film and does not feed skin bacteria. Very acne-prone skin can occasionally find heavy long-wear films harder to remove, so thorough cleansing helps.

Is Trimethylsiloxysilicate a UV filter?

No. Trimethylsiloxysilicate is a film former, not a UV filter, so it does not absorb or block UV light on its own. Its job is to lock the actual sunscreen filters into a water-resistant film so they stay put. The protection still comes from the listed UV filters; this ingredient just helps them last.

Is Trimethylsiloxysilicate natural?

No, it is synthetic. Trimethylsiloxysilicate is a silicone resin built from silicon and oxygen in the lab, and it does not occur in nature. Synthetic here simply means it was engineered for a durable, water-resistant finish, not that it is unsafe.

Sunscreens with Trimethylsiloxysilicate

We rate 297 sunscreens that contain it, showing the top 10 by overall score:

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