Disodium Phosphate

Disodium phosphate is a “behind-the-scenes” ingredient that is most commonly used as a buffering agent/pH adjuster in skin care and other cosmetic formulations. It also functions as a corrosion inhibitor to prevent the rusting of metals used in packaging. As a raw material, disodium phosphate is a hygroscopic powder (meaning it will absorb moisture from air upon exposure but just how much is dependent on the humidity and temperature). Technically it is not a fragrance ingredient (it is odorless in and of itself) yet it can help intensify other fragrance/flavor ingredients if present in a formula. The 2021 Cosmetic Ingredient Review of disodium phosphate surveyed 280 products containing 0.000054-2.9% of this ingredient, where it was deemed, “safe in the present practices of use and concentration in cosmetics as described in this safety assessment, when formulated to be nonirritating.” In another nod to this ingredient’s safety, the U.S. FDA has determined that it is generally recognized as safe (GRAS) as a direct food additive.