Artificial Food Dyes: The Color That Took 35 Years to Pull
In January 2025, the FDA finally revoked its authorization for Red No. 3, a synthetic dye that turns candy, supplements, and medications a bright cherry red. The dye caused thyroid tumors in male rats. That finding wasn't new. The FDA had banned Red 3 from cosmetics in 1990 on exactly the same evidence, then left it in food and swallowed drugs for another thirty-five years.
Read that timeline again. The same agency, looking at the same cancer data, decided the dye was too dangerous to put on your skin but fine to put in your child's vitamin. For three and a half decades.
That gap is the whole story of artificial food dyes.
What they are and why they're in there
Red 40, Yellow 5, Yellow 6, Blue 1, Blue 2, Green 3, and the now-departing Red 3 are petroleum-derived colorants. They are made from the same crude-oil feedstock as fuel and plastics, purified into pigments.
Their function is entirely cosmetic. They make a supplement look like fruit, a drink look like it contains something it doesn't, a cereal look like a toy. The dye does nothing for the product except sell it to your eyes, and increasingly to a child's eyes. There is no nutritional, preservative, or stability reason for a capsule to be neon.
What the evidence actually shows
Two separate concerns, and they sit at different strengths.
The cancer signal is specific to Red 3, well documented in animals, and now acted on. That one is settled enough that even the FDA moved.
The neurobehavioral signal covers the rest. The landmark Southampton study, published in The Lancet in 2007, found that mixtures of common dyes increased hyperactivity and inattention in children. The effect was real enough that the European Union now requires foods containing those dyes to carry a printed warning: "may have an adverse effect on activity and attention in children." In 2021, California's state health assessment reviewed the literature again and reached the same conclusion. California has since moved to ban Red 3 statewide and to pull several dyes from school food.
So Europe labels them, California restricts them, the FDA banned one and still permits the rest. Same molecules, three different risk tolerances.
Where you're eating them
In food, dyes cluster in anything marketed on appearance: candy, sodas and sports drinks, brightly colored cereals, frostings, flavored snacks.
In the health aisle, they show up where they have the least excuse: chewable and gummy vitamins aimed at children, brightly coated tablets, protein and pre-workout powders dyed to match a flavor name. A blue raspberry that contains no raspberry gets its blue from Blue 1.
How to skip them
Read the ingredient line for color names with numbers: Red 40, Yellow 5, Yellow 6, Blue 1, Blue 2, Green 3, and Red 3 until it fully clears the shelves. Also watch for "artificial color" and "color added," which hide the specifics.
The clean alternatives are already everywhere, because color from food is trivial: beet juice, turmeric, spirulina, annatto, fruit and vegetable extracts. A supplement brand that colors with food, or doesn't bother coloring at all, has told you something about how it thinks. The neon ones told you something too.
If it took the FDA thirty-five years to act on a dye it already knew caused tumors, the move is not to wait for them on the rest.
Part of our running file on what's hiding in your supplements: Toxic Supplement Additives: What to Avoid and Why.