Chelating

Such ingredients bind metal ions that can enter cosmetics from water, raw materials, or packaging. When there are traces of calcium, magnesium, iron or copper in the formula, they can accelerate oxidation, change the color and smell of the product, and reduce its stability. Chelating agents "intercept" these ions and make them less reactive, so the product retains its claimed properties, transparency and uniform texture for longer. That is why they are often added to shampoos, face wash gels, creams and micellar products. (cosmeticsinfo.org)

For skin and hair, their effects are mostly indirect, but important: they help the formula work predictably and reduce the risk that the active ingredients will break down faster. In hair products, such components also reduce the effect of hard water, which can leave mineral deposits on the hair, impairing softness and shine. In addition, metal bonding helps to better preserve the color and odor of cosmetics and may support the effectiveness of some preservative systems. (cosmeticsinfo.org)

Typical examples are Disodium EDTA and Tetrasodium EDTA; phytic acid and its salts can also be used in this role. EDTA and its salts are one of the most common representatives of this function in cosmetics, as they effectively bind metal ions even in small concentrations and are widely used in formulas of various types. (cosmileeurope.eu)