Trisodium Ethylenediamine Disuccinate

What it is

Trisodium ethylenediamine disuccinate is a chelator structurally related to EDTA but built from succinic acid units; the [S,S] isomer used in cosmetics is readily biodegradable, unlike EDTA itself. It is used at similarly low levels to protect against metal-catalysed oxidation and colour change. The concentration survey behind the Cosmetic Ingredient Review's 2023 assessment gives the only mask-specific figure in this catalogue: the highest level reported for paste masks was 0.063%, against a maximum of 0.56% anywhere in products meant for contact with skin.

What it does well

• Protects the formula from trace metals while breaking down after use

  It performs the same stabilising job as EDTA, and the [S,S] stereoisomer is degraded by common soil and wastewater bacteria, which is the reason it is chosen.

  Moderate evidence

Where the EU stands

Sources (1)

Every link goes to the original: a journal, a PubMed record or an EU document.

1. [1]
   Safety Assessment of Trisodium Ethylenediamine Disuccinate and Tetrasodium Iminodisuccinate as Used in Cosmetics

   Cosmetic Ingredient Review · 2023

   Status: Final Report, released 31 March 2023, with no do-not-cite stamp on any page. On concentration it says: "the reported maximum concentration of use is 0.64% Trisodium Ethylenediamine Disuccinate in tonics, dressings, and other hair grooming aids; the greatest reported maximum concentration of use in products intended for dermal contact is 0.56% in moisturizing products." Its frequency-and-concentration table breaks out a mask row - Paste Masks (mud packs), 3 reported uses, 0.063% - which is a maximum reported to the survey rather than a typical level. The Expert Panel "concluded that Trisodium Ethylenediamine Disuccinate and Tetrasodium Iminodisuccinate are safe in cosmetics in the present practices of use and concentration described in the safety assessment." Checked 31 August 2026.