Ingredient dictionary

Tetrasodium Etidronate

The sodium salt of etidronic acid, a chelating agent that grabs stray metal ions like calcium and iron. Its main job is keeping a formula stable and clear. It is on the label of 5 products in our library. Checked against our library November 6, 2026.

The catch: none for most people; check the full product list if your skin reacts easily.

What Tetrasodium Etidronate does

Binds metal ions that can cloud or discolor formulas
Helps keep scent and color steady
Supports overall formula stability

Tetrasodium Etidronate is a synthetic ingredient. It starts as etidronic acid, a phosphorus-based acid made through controlled chemical reactions, and is then combined with sodium to form this salt. Its structure has several binding points, so it can hold onto metal ions such as calcium, magnesium, and iron.

Formulators use it because stray metal ions can cloud a formula, shift its color, change its scent, or speed up the breakdown of other ingredients. Tying those ions up helps a lotion stay smooth, clear, and consistent over time. It dissolves in water, so it blends into the water-based part of a formula without changing the feel much.

Good for

Often found in body lotions and similar leave-on products, where steady texture, color, and scent matter.

Be careful if

Nothing in particular for most skin types.

Frequently asked questions

Is Tetrasodium Etidronate safe for skin?

It is generally considered well tolerated in cosmetics at the levels used in finished products. Like any ingredient, a person can react to it, so patch testing a new product is a sensible habit for sensitive skin. If you notice redness, itching, or stinging, stop using the product.

Is Tetrasodium Etidronate the same as etidronic acid?

Not quite. Etidronic acid is the parent acid, and tetrasodium etidronate is its sodium salt. The sodium form dissolves easily in water, which suits water-based formulas. Both forms bind metal ions in a similar way.