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Hydroxide K

What Hydroxide K is & what it does

Potassium hydroxide (listed as Hydroxide K) is a strong alkali used in tiny amounts purely as a pH adjuster. It neutralises acids so the finished sunscreen sits at a skin-friendly pH and the other ingredients stay stable. None of the raw, caustic material remains active in the final product.

What is Hydroxide K doing in my sunscreen?

Hydroxide K is the INCI label name for potassium hydroxide, used in tiny amounts purely as a pH adjuster. It neutralises acids so the finished formula sits at a skin-friendly pH and the rest of the ingredients stay stable. None of the raw lye remains active in the final product.

Is Hydroxide K safe in cosmetics?

Yes. Although concentrated potassium hydroxide is caustic on its own, in finished products it is used at minute, fully-neutralised levels that are safe and non-irritating. It is a standard, well-reviewed pH adjuster used across many sunscreens and skincare products.

What else is Hydroxide K called?

Hydroxide K is the INCI name for potassium hydroxide, also known as potash lye or caustic potash. It is the potassium counterpart to sodium hydroxide and is used in the same way, to fine-tune a formula's pH.

Does Hydroxide K clog pores?

No. It is a water-soluble alkali used in trace, neutralised amounts to balance pH, not an oil or wax, and it is not flagged as comedogenic. It plays no role in pore-clogging.

Is Hydroxide K natural?

No, it is synthetic, typically made by electrolysis of a potassium salt solution. It is used only in tiny, fully-neutralised amounts to adjust pH, so none of the raw, caustic material remains active in the finished product.

Sunscreens with Hydroxide K

We rate 268 sunscreens that contain it, showing the top 10 by overall score:

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