FD&C Red #3.
Colors your supplement red. That's it. No health function whatsoever.
Reviewed March 2026
- Category
- General
- Also filed under
- Provides cherry red coloring
What FD&C Red #3 is, and what it does.
- Does it work
- All risk, zero benefit. Why is this in a health product?
- How much to take
- Not applicable. You shouldn't be taking this on purpose.
- Time to feel it
- The soluble dye dissolves with the tablet within minutes and is cleared. It is present for shade only, not as an active, so it has no onset of its own.
- The first dose
- The soluble dye dissolves with the tablet within minutes and is cleared. It tints the product and nothing else, so day one brings no change you would feel.
- With regular use
- Human risk at supplement doses is debated but unnecessary.
- How well tolerated
- FDA revoked authorization in 2024. Being phased out by 2027. California already banned it.
- How it feels
- No taste and no sensation at the level used for colour. What registers is the shade of the tablet, which is the only reason it is in the formula.
- The overlooked benefit
- Every molecule carries four bound iodine atoms and the colour fades in light, which is why products coloured this way are usually packed in opaque bottles.
The proof, claim by claim.
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
- Causes thyroid tumors in rats
- Dangerous at supplement doses in humans
Questions people ask about FD&C Red #3.
- When will it be completely gone?
- The FDA gave manufacturers until January 2027 to reformulate. You might still see it on shelves until then.
- Is Red #40 the same thing?
- No. Red #40 (Allura Red) is a different dye and hasn't been banned. They're often confused because of similar names.
- Should I throw out supplements containing it?
- Don't panic. The amount in supplements is tiny. But when it's time to reorder, choose a brand without artificial dyes.
- Why was it in health products in the first place?
- Marketing. Red-colored supplements look more 'vibrant' and 'natural' to consumers. Ironic, since the dye is completely synthetic.
- Are European supplements dye-free?
- The EU requires warning labels on products with Red #3, which effectively pushed most manufacturers to remove it. The US is catching up.
Why these belong in the same formula. Each row says what the basis is, from settled biochemistry through to a trial that measured the pair.
Erythrosine is an iodinated xanthene dye, and part of its iodine is released and joins the body's iodide pool. Intake therefore adds to the total iodine load alongside any iodine or kelp in the same formula.
Erythrosine is a xanthene dye and its colour depends on an intact conjugated chromophore. Ascorbic acid is a strong reducing agent, and reducing conditions in a wet or high-moisture formulation drive fading. This is a stability interaction between an excipient and an active, not a nutritional one.
The colourant is supplied as a water-soluble disodium salt whose solubility falls sharply as pH drops toward the acid range, where the free acid form precipitates. An alkaline buffer keeps it in solution. An acidified formula can cloud or throw a precipitate. Formulators pick the pH deliberately for that reason.
Opaque mineral fillers such as calcium carbonate sit alongside colourants in tablet coats and change the apparent shade at a given dye load. The interaction is optical and physical rather than chemical. It affects how much colourant a coating needs, nothing about how either ingredient behaves in the body.
Talk to a doctor before taking FD&C Red #3 if any of these apply to you: Linked to thyroid tumors in animal studies, Banned in cosmetics since 1990, FDA announced ban in food/supplements (phase-out in progress), Already banned in California (2027 effective date). These are flags to check first, not effects FD&C Red #3 is known to cause.
Not medical advice. Show the label to your pharmacist.What FD&C Red #3 actually does.
Red 3 is a lab-made dye, not a nutrient. It's added purely for color and doesn't do anything nutritionally in a formula.
The dye molecule contains iodine locked into its own structure, but that's not the same as the iodide your body gets from food or iodized salt.
How well this dye dissolves in a liquid depends on acidity. In more acidic products it can separate out instead of staying dissolved.
Light breaks this dye down and changes its color over time, which is why products colored with it are usually packaged to keep light out.
Where FD&C Red #3 comes from.
It is made in a chemical plant from petroleum-derived starting materials, then iodine is added to the molecule to give the shade. Nothing about it is extracted from a plant or an animal, and it is in a product for colour only.
Chemically synthesised. The molecule is identical to the one a plant or an animal makes, and building it deliberately means a known purity, a fixed dose and no crop contaminants. For several nutrients this is the only route that reaches a usable amount.
Resorcinol and phthalic anhydride, both derived from petroleum aromatics in modern production. Older literature describes the class as coal tar dyes, which reflects the historical feedstock rather than current practice.
Resorcinol and phthalic anhydride are condensed under acid catalysis to give fluorescein, the parent xanthene structure.
Fluorescein is iodinated to substitute four iodine atoms onto the ring system, producing tetraiodofluorescein. The iodine count is what distinguishes this colourant from its brominated and chlorinated relatives.
The product is converted to the disodium salt, recrystallised and washed to control residual intermediates and unreacted iodine species.
Dye content, subsidiary colours and residual intermediates are assayed against a colour additive specification, and the material is blended with diluent to a declared strength.
Sold either as the soluble sodium salt or laked onto alumina to give an insoluble pigment for tablet coatings.
Manufacturer, plant location and diluent identity are not usually stated on a supplement label; only the colour additive name appears.
Getting FD&C Red #3 from food.
The whole-food sources on file. A supplement closes the gap, it does not replace dinner.
A gram-for-gram figure (how much of each you would eat to match a dose) will appear here once it is sourced and reviewed. This page will not print a number it cannot cite.
The forms it comes in.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.
