Tetrasodium Etidronate

What is Tetrasodium Etidronate?

Tetrasodium Etidronate is the tetrasodium salt of etidronic acid, a synthetic organophosphonate compound chemically known as 1-hydroxyethane-1,1-diphosphonic acid tetrasodium salt. It appears as a white powder soluble in water and is widely incorporated into rinse-off and leave-on cosmetics such as cleansers, shampoos, conditioners, and lotions. In formulations, it works by forming tight complexes with polyvalent metal ions like calcium, magnesium, iron, and copper from water or ingredients. This chelation inhibits metal-catalyzed reactions that lead to product instability, including peroxide formation, color changes, and emulsion breakdown. Beyond chelation, it supports emulsion integrity by reinforcing interfacial films and modulates viscosity for optimal spreadability and suspension of actives, thereby extending shelf life and maintaining desirable sensory properties in diverse cosmetic systems.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1-2 View on EWG →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Chelating agent
Binds to metal ions to prevent them from affecting product stability or skin.
Emulsion stabilizer
Improves emulsion robustness by preventing droplet coalescence and phase separation, often by thickening, structuring, or strengthening the interfacial layer.
Viscosity controlling agent
Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.

Benefits

Binds metal ions to safeguard formulations from oxidative damage and rancidity.

Strengthens emulsions for better phase separation resistance.

Controls viscosity to enhance product texture and application ease.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Users of aqueous-based cleansers and shampoos for stable performance.
Those with rare hypersensitivity to phosphonate compounds.
Individuals preferring products with natural extracts that oxidize easily.
Individuals preferring formulations without synthetic chelators.
People seeking reliable moisturizers with consistent consistency over time.
Users opting for minimalist products free of stabilizing salts.

Safety Notes

  • Recognized as safe for use in cosmetics at typical concentrations.
  • Exhibits low potential for skin irritation or sensitization.

Frequently Asked Questions about Tetrasodium Etidronate

What does Tetrasodium Etidronate do in skincare?

It chelates metal ions to prevent formulation instability, oxidation, and discoloration while aiding emulsion and viscosity control.

Is Tetrasodium Etidronate safe for daily use?

Yes, it is considered safe in cosmetics with low hazard ratings and minimal irritation potential from authoritative reviews.

In which products is it commonly found?

Typically in shampoos, body washes, conditioners, and lotions to maintain stability and performance.