Dehydroacetic Acid Good Conservante No known benefits Dehydroacetic Acid description Dehydroacetic acid is a synthetic preservative used in amounts of 0.6% or less where it’s proven to be safe and effective. Dehydroacetic acid is characterized as a white to cream crystalline powder. Sometimes its salt form (known as sodium dehydroacetate) is used, as it is more soluble in certain types of cosmetic formulas. Dehydroacetic acid is most effective on fungi.