EDTA, Ethylenediaminetetraacetic acid is a molecule which complexes metal ions in aqueous environments. It is available in four neutralizations, two of which, Disodium EDTA and Tetrasodium EDTA, are commonly used in the cosmetics. Generally, the choice of which product to use is determined by the pH of your product. Tetrasodium EDTA is recommended for alkaline products, like most handcrafted soap. It can also be used in creams, lotions and surfactant systems. If your formulation is clear or transparent, it may be preferred over Disodium ETDA as it is much more soluble in water. Either form works synergistically with your preservative to improve preservative efficacy. In soaps, it can counteract the defoaming action of hardness ions, reducing soap scum and improving lather.
