Sodium levulinate is the sodium salt of levulinic acid, a keto acid derived from the degradation of cellulose. In cosmetics and personal care products, sodium levulinate functions as a natural preservative. The use of preservatives in cosmetics is important because these types of products have a high potential for microbial contamination and growth. The most susceptible products are creams and lotions that are packaged in jars, opened frequently, and applied to the skin with the fingers. Inadvertent contamination may also occur after the use of makeup brushes around the eyes or other parts of the face that touch the skin and the cosmetic repeatedly.

Microbial contamination not only causes product spoilage, but can also lead to significant health problems, from skin irritation to infections. Sodium levulinate is an appealing option to brands of natural cosmetic products because it is a natural alternative to the synthetic preservatives. Another benefit of sodium levulinate is that it will not alter the pH level or the color of the cosmetic formulation. Lastly, sodium levulinate is said to provide skin-conditioning effects, which makes it an excellent addition to creams, lotions, and other types of moisturizers.