What it is
CI 77492 is yellow iron oxide, an inorganic colorant consisting of hydrated iron(III) oxide that can range from a light lemon to an orange-yellow shade depending on how it is made. It gives the yellow component of foundations, tinted sunscreens and tone-up creams, and when blended with red and black iron oxides it produces the warm, flesh-toned shades used across complexion products. In sunscreens it contributes to tint and tone-up effects rather than acting as a UV filter. Iron oxide pigments are prized for being strongly colored and stable.
Safety & warnings
Cosmetic-grade yellow iron oxide is generally well tolerated and is broadly used in complexion makeup, with reference sources noting very low irritancy and no comedogenicity in this pigment class. Because cosmetic iron oxides are produced to defined purity specifications, they are widely considered suitable even for sensitive or reactive skin.
History
Iron oxides are among the oldest known pigments: iron-oxide-based pigment was used in prehistoric cave art, with examples dated to roughly 15,000 BCE. Their long-standing use as inexpensive, strongly colored and nontoxic colorants carried over into modern industries, including standardized cosmetic and food-grade (E172) applications.