Tetrasodium EDTA is a sodium salt of ethylenediaminetetraacetic acid (diamine amino acid), a widely used chelating agent against metal ions. It is similar to disodium EDTA, but all four carboxylic groups are occupied with sodium, making this ingredient solution alkaline pH value ~11. Thus, besides being a chelating agent, it can serve as a pH balancer in acidic formulas.
In a chemical view, Tetrasodium EDTA has six active functional groups (two amino and four carboxylic), which enables it to form complexes (chelating action) with metal ions, including heavy metals that leave harmful effects on skin health and complexion. It binds, sequesters, and eliminates harmful ions, detoxifying the skin. Furthermore, Tetrasodium EDTA captures Ca2+ and Mg2+ ions from hard water and makes it softer, enhancing the effectiveness of surfactants in cleansing applications.
Combination with other ingredients
Tetrasodium EDTA can increase the penetration rate of other ingredients, improving adsorption levels and the entire effectiveness of preparation. Furthermore, it exhibits antibacterial and anti-biofilm properties helpful in wound healing and skin bacteria-induced conditions like acne while enhancing the preservatives efficiency and shelf-life of the product. This multifunctional ingredient also increased the antioxidant action of vitamins such as vitamin E and C.
Multiple clinical studies showed no absorption of an EDTA and its salt through the skin, thanks to large molecule size and limited lipophilicity. Therefore, the Cosmetic Ingredient Review Expert Panel included Tetrasodium EDTA in the ingredients list, which is safe for use in personal care applications.