Which is Healthier: Red 3 or Red 40?

December 28, 2025 •

3 min read

In early 2025, the FDA finally banned Red Dye No. 3 from use in foods and ingested drugs due to concerns over cancer risks identified decades ago. This landmark decision has caused many consumers to question the safety of its synthetic sibling, Red Dye No. 40, and wonder which of the two is actually the healthier option.

Quick Summary

An in-depth look at Red 3 and Red 40, comparing their chemical properties, health risks, and regulatory status to determine which food dye is the safer alternative. Examine the science behind consumer concerns regarding hyperactivity, allergies, and carcinogenicity.

Key Points

Regulatory Difference: Red 3 was federally banned from foods in 2025 due to carcinogenicity findings in animals, while Red 40 remains FDA-approved.
Carcinogenic vs. Controversial: Red 3's proven animal carcinogenicity led to its ban, whereas Red 40's concerns revolve mainly around behavioral issues, particularly in sensitive children.
Behavioral Concerns: Both dyes have been linked to neurobehavioral effects like hyperactivity, but the evidence is stronger and more widely discussed for Red 40 due to its continued prevalence.
International Scrutiny: Europe mandates warning labels for Red 40, signaling greater caution than the U.S., which only recently banned Red 3, years after other nations.
Healthier Alternatives: The healthiest option is to avoid all synthetic dyes, including Red 40, and choose products that use natural colorings from sources like beets or paprika.
Reading Labels is Key: Until the Red 40 is potentially phased out, informed consumers should always read labels to identify and choose products without synthetic dyes.

The Chemical Composition and Regulatory History of Red Dyes

Both Red Dye No. 3 (Erythrosine) and Red Dye No. 40 (Allura Red AC) are synthetic color additives derived from petroleum. However, their chemical structures and regulatory paths have differed significantly.

Red 3 is an iodine-based compound. Studies in the 1980s linked high doses to thyroid cancer in male rats, leading to its ban in cosmetics in 1990. Following sustained pressure and based on the Delaney Clause, the FDA banned Red 3 in food and ingested drugs in January 2025.

Red 40 is not iodine-based and is currently FDA-approved. However, it is not without controversy. The European Union mandates a warning label about potential effects on activity and attention in children. Concerns also exist in the U.S. from consumer groups and some states, though the FDA deems it safe in regulated amounts.

Comparing the Health Concerns Associated with Red 3 and Red 40

Red 3's ban was primarily due to a proven link to cancer in animal studies, while concerns about Red 40 largely focus on behavioral effects in children.

Red 3 Risks: The main concern leading to Red 3's ban was its association with thyroid tumors in male rats. It has also been linked to endocrine disruption and increased oxidative stress in the brain.
Red 40 Risks: Research has linked Red 40 to neurobehavioral issues, specifically hyperactivity and ADHD symptoms in sensitive children. Other less frequent side effects can include allergic reactions (hives, swelling), migraines, and potential mild inflammation.

Red 3 vs. Red 40: A Comparative Table


Feature	Red Dye No. 3 (Erythrosine)	Red Dye No. 40 (Allura Red AC)
Regulatory Status (U.S. FDA, 2025)	Banned in food and ingested drugs.	Approved for use in regulated amounts.
Carcinogenic Risk	Linked to thyroid cancer in male rats at high doses. The basis for the 2025 ban.	No conclusive evidence of causing cancer in humans, though contains trace amounts of carcinogens.
Behavioral Effects	Associated with neurobehavioral problems, especially hyperactivity in children.	Linked to hyperactivity and ADHD symptoms, particularly in sensitive children.
Chemical Properties	Contains iodine; shown to disrupt thyroid function.	Does not contain iodine; derived from petroleum.
International Regulation	Banned or heavily restricted in Europe.	Requires a hyperactivity warning label in the European Union.
Current U.S. Usage	Previously in items like maraschino cherries and candy; now being phased out.	Widely used in cereals, sports drinks, snacks, and medications.

Making Informed Choices

With Red 3 being phased out of U.S. foods, Red 40 is the prevalent artificial red dye. However, concerns about its link to behavioral issues, especially in children, suggest caution. Many health advocates recommend minimizing or avoiding synthetic dyes and choosing natural colorants instead, such as those derived from beet juice or anthocyanins. Checking ingredient labels for names like “FD&C Red No. 40” or “Allura Red AC” is essential.

Conclusion: The Verdict on Which is Healthier

Based on regulatory actions and health concerns, Red 3 is clearly less healthy than Red 40. Red 3's ban was due to evidence of causing cancer in animal studies. Red 40, while FDA-approved, faces controversy regarding potential links to hyperactivity, allergies, and other issues, particularly for children. Neither synthetic dye is considered healthy. The healthiest approach is to reduce or eliminate both, prioritizing foods with natural coloring agents.

Lists and Information

Foods That Historically Contained Red 3

Maraschino cherries
Seasonal candies like conversation hearts
Some fruit cocktails
Strawberry-flavored milk drinks

Foods That Commonly Contain Red 40

Soft drinks and sports drinks
Breakfast cereals, such as Froot Loops
Candy, including Skittles and gummy bears
Processed snack foods like Doritos
Flavored yogurts and ice creams
Some condiments and salad dressings

Natural Alternatives to Red Dyes

Beet juice or beet powder
Radish extract
Paprika oleoresin
Anthocyanins from fruits like purple sweet potato
Lycopene from tomatoes

What the Science Says

Red 3 is carcinogenic: The key evidence for the Red 3 ban was its link to thyroid tumors in rats, fulfilling the requirements of the Delaney Clause.
Red 40 and behavior: Multiple scientific reviews confirm a link between synthetic food dyes and adverse neurobehavioral effects in children, including worsening ADHD symptoms.
More research needed: Long-term, high-quality human studies are still needed to fully understand the effects of Red 40 and other synthetic dyes.

For Your Consideration

Given the evidence linking Red 40 to behavioral issues in sensitive individuals and its controversial status internationally, consumers should consider these factors. A diet rich in whole foods naturally avoids these synthetic additives. Reading labels and choosing brands with natural colorings are practical steps to reduce exposure. While Red 40 is FDA-approved, minimizing or avoiding synthetic dyes is the healthiest choice.

Center for Science in the Public Interest: Red 3 ban

Frequently Asked Questions

Red Dye 3 is definitively worse for health. In January 2025, the FDA banned Red Dye 3 from food and ingested drugs due to studies linking it to thyroid cancer in rats, a risk not associated with Red Dye 40.

The FDA banned Red Dye 3 based on the Delaney Clause, a law prohibiting food additives proven to cause cancer in animals or humans. Studies in the 1980s linked Red 3 to thyroid cancer in male rats, and after decades of inaction, the FDA finally enforced the ban in 2025.

The main health concerns with Red 40 are its links to increased hyperactivity and worsened ADHD symptoms, particularly in sensitive children. Some individuals also report allergic reactions like hives and migraines.

No, Red Dye 40 has not been conclusively proven to cause cancer in humans. While some studies have suggested potential links, and it contains trace carcinogens, the FDA still considers it safe for consumption within regulated limits.

Yes, in the European Union, products containing Red 40 must carry a warning label stating they "may have an adverse effect on activity and attention in children." This is based on research suggesting a link between the dye and hyperactivity.

Red Dye 40 is the most widely used synthetic red food coloring in the United States today. It is far more prevalent in processed foods and beverages than Red 3 was prior to its ban.

Natural alternatives to artificial red dyes include beet juice, paprika, anthocyanins from fruits like purple sweet potatoes or radishes, and carmine (derived from cochineal insects).