What it is
Red 4 is a water-soluble synthetic azo dye that produces a red to orange-red shade. In cosmetics it is used purely for coloring the product, with no skin-conditioning or protective role. It is typically present at very low levels sufficient to achieve the desired tint.
Safety & warnings
As a synthetic azo colorant used at very low concentrations, Red 4 is generally well tolerated on skin. Permitted uses and concentration limits for color additives vary by region, so its inclusion is restricted to approved applications. Individuals with known sensitivity to azo dyes may wish to take note.
Origin & sourcing
Synthetic, produced by chemical synthesis as a sulfonated monoazo dye.
Questions everyone asks
What is Red 4 used for in sunscreen?
It is a colorant added in small amounts to give the product a specific tint; it does not contribute to sun protection.
Is Red 4 a natural or synthetic ingredient?
It is a synthetic azo dye made by chemical synthesis.