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Ingredient · INCI reference

Potassium Stearate

The potassium salt of stearic acid, used in cosmetics as an emulsifier, surfactant, and cleansing agent.

What it is

Potassium Stearate is a soap formed from stearic acid and potassium hydroxide. In formulations it functions as an emulsifier and surfactant, helping to blend oil and water phases and to stabilize emulsions, and it can contribute to cleansing and texture. It is commonly generated in situ when stearic acid is neutralized in a cream base.

Safety & warnings

As a fatty-acid soap, potassium stearate is widely used and generally well tolerated. Like other soaps it is mildly alkaline, so high levels in rinse-off or leave-on products can be drying for some users.

Origin & sourcing

Can be natural-derived or synthetic. The stearic acid portion is typically sourced from vegetable or animal fats and is then reacted with a potassium base to form the salt.

Questions everyone asks

What does potassium stearate do in a formula?

It works as an emulsifier and surfactant, helping oil and water mix and stabilize, and it can aid cleansing and adjust texture.

Is it a kind of soap?

Yes, it is the potassium salt of stearic acid, which makes it a fatty-acid soap used to emulsify and stabilize products.

Sources & references

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