Iron Oxides

This ingredient is a combination of red, black, and yellow iron oxide pigments. This combination of colors is usually found in foundation, because it results in a "skin" color.

A note on EU vs US ingredient lists:

The EU typically uses CI numbers for colorants when applicable, such as CI 77489. In the US, iron oxides are regulated as color additives and "iron oxides" is the most commonly used name in US cosmetic practice.

Blue light blocking

A 2021 paper looked at skincare formulations containing iron oxides and found that they reduced transmission of blue light when measured optically. In simple terms, the pigment particles helped block or scatter part of the visible light spectrum in lab testing and the authors suggest this could translate into better protection against blue-light-related skin effects.

There is also clinical and experimental research showing that tinted products containing iron oxides can reduce visible light-induced pigmentation:

• In one 2020 study, an iron oxide containing tinted sunscreen provided significantly better protection against visible light induced pigmentation compared to an untinted sunscreen in Fitzpatrick IV individuals.
• Reviews on melasma photoprotection often recommend tinted sunscreen that contain iron oxides as part of managing pigmentation trigger by visible light.

Please note, whether a product reduces visible or blue light depends on things like:

• How much pigment is used
• The shade depth
• How evenly it's applied
• The overall formula

INCI and Cosing

In the EU's CosIng database, iron oxides are only listed as a colorant. CosIng groups ingredients by their main cosmetic role, such as colorant, preservative, or UV filter.

Though studies say iron oxides can "attenuate blue light", they're describing an optical property and not an officially recognized cosmetic function.

So CosIng isn’t contradicting the research. It’s just classifying iron oxides by what they officially are: pigments that add color.