Potassium sorbate is the potassium salt of sorbic acid used as a preservative in cosmetics. Although it may be naturally derived, most potassium sorbate is produced synthetically. It is almost always used with other preservatives because of its weaker activity.
The independent Cosmetic Ingredient Review Panel found that potassium sorbate is safe in amounts up to 10%; it is most commonly used in skin care products in amounts of 1% or less. https://www.paulaschoice.com/ingredient-dictionary/ingredient-potassium-sorbate.html?q=Potassium%20Sorbate&fdid=ingredients