Tetrasodium EDTA

What is it?

A higher-substitution sodium salt of EDTA (ethylenediaminetetraacetic acid), used as a chelating agent in cosmetic formulations to bind trace metal ions and improve product stability; the same chelating function as the already-catalogued Disodium EDTA.

What does it do?

According to PubMed, a 2002 Cosmetic Ingredient Review (CIR) Expert Panel safety assessment of EDTA and its salts, including tetrasodium EDTA, found no absorption of an EDTA salt through intact skin in clinical tests, and concluded these ingredients are safe as used in cosmetic formulations at typical use concentrations, while noting EDTA's chelating action can increase the skin penetration of other co-formulated ingredients (DOI: https://doi.org/10.1080/10915810290096522). A 2023 L'Oreal formulation study used EDTA (and tetrasodium EDTA's close relative, disodium EDTA) as the benchmark metal-chelating stabilizer for retinol formulations, against which a newer, more biodegradable EDDS-based alternative was compared (DOI: https://doi.org/10.1111/ics.12853).

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