Blue No. 2 Lake

Blue No. 2 Lake is a synthetic color additive used to impart a blue hue to foods. It is the aluminum lake of Indigotine (also known as Blue No. 2), which is a synthetic dye derived from petroleum. A "lake" is created by combining the dye with a metallic salt, typically aluminum, making it insoluble in water.

Manufacturers add Blue No. 2 Lake to color foods, especially those with low moisture content or high fat, where the color needs to remain stable and not bleed. It is commonly found in products like popcorn, peanuts, snacks, chocolate, candy, and baked goods.

Blue No. 2 Lake is an FDA-approved color additive for use in food. The FDA has concluded that it is safe for consumption under approved conditions. JECFA has evaluated Indigotine (Blue No. 2) and set an acceptable daily intake, and EFSA has also evaluated it and set an acceptable daily intake. Some studies have explored a potential link between synthetic food dyes and hyperactivity in children; however, the FDA states there is no conclusive evidence that food color additives cause hyperactivity in the general population, though some children may be sensitive. In April 2025, the FDA announced a plan to phase out petroleum-based synthetic dyes, which includes Blue No. 2.