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Onsen-Sui

What Onsen-Sui is & what it does

Onsen-Sui is the Japanese term for natural hot spring water. In skincare and sunscreen formulas it is used as the water phase or as a mineral-rich aqueous base. It is valued for the dissolved minerals it naturally contains, which formulators highlight as a gentle, soothing-feeling source of water for the product.

Is Onsen-Sui safe?

Onsen-Sui is natural hot spring water used as the water phase or a mineral-rich base in cosmetics, and it is generally considered safe for topical use. It is valued for its dissolved minerals. As with any product, patch testing is reasonable if your skin reacts easily.

What does Onsen-Sui do in skincare?

In skincare and sunscreen formulas, Onsen-Sui serves as the water phase or a mineral-rich aqueous base. The minerals it naturally contains are highlighted by formulators as a gentle, soothing-feeling source of water. It forms the foundation that carries the other ingredients in the formula.

Is Onsen-Sui natural or synthetic?

Onsen-Sui is natural. It is water sourced from hot springs and carries naturally dissolved minerals. It may be filtered or treated for cosmetic use, but its origin is a natural spring rather than a synthetic process.

Sunscreens with Onsen-Sui

We rate 8 sunscreens that contain it:

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