CI 16035 (Red 40 / Allura Red) vs CI 19140 (Yellow 5 / Tartrazine): which is worse?

What is CI 16035 (Red 40 / Allura Red)?

CI 16035 (Allura Red AC) is a red azo dye that is one of the most widely used synthetic colorants in both food and cosmetics. In cosmetics it provides vivid red coloring in products for external use.

What is CI 19140 (Yellow 5 / Tartrazine)?

CI 19140 (tartrazine) is an azo dye that produces a bright lemon-yellow color. It is approved for use in food (as FD&C Yellow 5) and cosmetics in the US. In cosmetics, it is used in products applied to the skin, nails, and hair.

Documented risks

CI 16035 (Red 40 / Allura Red): Topical cosmetic use of CI 16035 is considered safe. Systemic absorption from properly formulated rinse-off or leave-on products is minimal. Unlike food consumption (where concerns include potential behavioral effects in hyperactive children), topical cosmetic exposure does not raise the same issues. The CIR and FDA have assessed it as safe for cosmetic use. It is not a carcinogen for topical applications.

CI 19140 (Yellow 5 / Tartrazine): CI 19140 is considered safe for cosmetic use by the CIR when used at regulated concentrations in rinse-off and leave-on external products (excluding eye area). The EU restricts its use and requires allergen labeling for tartrazine-sensitive individuals. It is not approved for use in products applied near the eyes in the EU. Some aspirin-sensitive individuals may also react to tartrazine. There is no evidence of carcinogenicity or systemic toxicity from topical cosmetic use.