Understanding the Controversy: How Bad Is Red Dye Number 40 for You?

October 12, 2025 •

3 min read

Made from petroleum, Red Dye 40 is one of the most widely used synthetic food dyes, found in over 38,000 food products in the U.S. alone. This prevalence sparks a critical question for consumers focused on nutrition and wellness: How bad is red dye number 40 for you?

Quick Summary

Red Dye #40 is a common synthetic additive derived from petroleum, associated with potential health risks. Concerns include hyperactivity in sensitive children, allergic reactions, and possible links to gut inflammation and DNA damage based on animal studies. Its regulatory status varies globally, prompting many consumers to seek natural alternatives.

Key Points

Source and Purpose: Red Dye #40 is a synthetic color additive derived from petroleum, used to make processed foods more visually appealing.
Behavioral Concerns: It has been linked to increased hyperactivity and worsened ADHD symptoms in sensitive children, though it does not cause ADHD itself.
Allergy Risk: Allergic reactions to Red Dye #40 are possible but rare, with symptoms like hives, itching, or swelling.
Emerging Gut Health Issues: Recent animal studies have linked Red Dye #40 to DNA damage, gut inflammation, and a altered microbiome, suggesting potential long-term risks.
Global Regulatory Differences: The EU requires warning labels on products containing the dye, while some countries have banned it entirely, and certain U.S. states are restricting its use.
Natural Alternatives: Consumers can find natural alternatives derived from sources like beetroot, paprika, and pomegranate, especially in less-processed or organic foods.

What is Red Dye #40?

Red Dye #40, also known as Allura Red AC or FD&C Red No. 40, is a synthetic color additive derived from petroleum. It is widely used in processed foods and beverages to enhance their visual appeal. The dye is also used in pharmaceuticals and cosmetics. While certified as safe by the FDA, which also tests batches for purity, Red Dye #40 has faced controversy and debate for decades due to potential health concerns raised by some studies and consumer groups.

Potential Health Concerns Associated with Red Dye #40

Regulatory bodies like the FDA and WHO deem Red Dye #40 safe for most individuals within acceptable daily intake levels. However, ongoing research indicates potential health issues, particularly for sensitive people. The main concerns include:

Hyperactivity and ADHD in Children

There is a persistent controversy regarding the link between Red Dye #40 and neurobehavioral problems in children. Studies, including the 2007 Southampton study, have suggested a connection between artificial food dyes and increased hyperactivity. A 2021 report by California's OEHHA concluded that synthetic food dyes could worsen neurobehavioral issues in some children.

Exacerbation, not Causation: Experts note that Red Dye #40 doesn't cause ADHD but might amplify symptoms like hyperactivity and irritability in susceptible children.
Individual Sensitivity: The FDA acknowledges that sensitivity to color additives can vary among individuals.

Allergies and Hypersensitivity Reactions

Though considered rare, synthetic food dyes can trigger allergic or hypersensitivity reactions in some individuals. Symptoms can include hives, itching, swelling, asthma-like issues, and migraines. These reactions are distinct from true IgE-mediated allergies, which are extremely uncommon with synthetic dyes. Some people report sensitivities causing headaches or digestive upset.

Gut Health and Inflammation

Animal studies have raised concerns about Red Dye #40's effects on gut health. Continuous exposure harmed the gut microbiome and caused inflammation in mice. The study also indicated DNA damage in cell cultures and animals.

Potential Carcinogenic Contaminants

Red Dye #40 itself is not classified as a carcinogen, but it can contain trace amounts of carcinogens like benzidine. While the FDA certifies batches for purity, the presence of these contaminants, even in small amounts, is a concern for long-term exposure. The evolving understanding of synthetic dye safety is highlighted by actions like the ban on Red Dye 3 due to cancer risks.

A Global Perspective on Red Dye #40

Regulatory approaches to Red Dye #40 differ globally due to ongoing debate and varying interpretations of scientific evidence.


Feature	United States	European Union	Norway and Iceland	California
Status	Approved by FDA, potential re-evaluation underway	Approved, with warning label requirement	Banned	Banning from school meals starting 2028
Labeling	Must be listed as FD&C Red No. 40 or Allura Red AC	Must include warning about effects on children's activity and attention	Not applicable	Will be restricted in some products
Impact on Companies	No federal mandate for formulation changes	Many companies have reformulated products for the European market to avoid warnings	Companies must use natural colorants	Prompting broader review of synthetic dye use
Stance on Safety	FDA deems safe for general population, notes sensitivity in some children	Precautionary approach due to behavioral concerns	Strict precautionary principle	State-level regulation based on evidence

How to Limit Your Intake and Identify Alternatives

To limit Red Dye #40 intake, focus on whole, unprocessed foods and carefully read product labels.

Reading Labels: Look for 'Red 40', 'FD&C Red No. 40', 'FD&C Red No. 40 Aluminum Lake', or 'Allura Red AC' on ingredient lists.

Commonly found in foods like:

Breakfast cereals, candy, fruit snacks, gelatins
Dairy products (yogurt, ice cream)
Soda, sports drinks, fruit juices
Baked goods and cake mixes
Some medications and cosmetics

Natural Color Alternatives: Natural ingredients like beetroot (red/pink), paprika (red-orange), pomegranate juice (rich red), annatto (reddish-orange), and carmine (red) can provide color.

Conclusion: A Balanced Perspective on Red Dye #40

The health impact of Red Dye #40 varies depending on individual factors. While regulatory bodies like the FDA consider it safe within current limits, scientific evidence suggests potential risks, particularly for sensitive children. The link to hyperactivity is noted in some individuals, and animal studies indicate potential long-term issues like inflammation and DNA damage. Since Red Dye #40 offers no nutritional value and is primarily in processed foods, choosing natural alternatives or reducing consumption is a sensible approach for those with concerns. Reading product labels is key to making informed dietary choices.

Frequently Asked Questions

No, Red Dye #40 does not cause ADHD. However, some studies have found that it can exacerbate or worsen hyperactivity and other behavioral symptoms in children who are already sensitive to it, including those with ADHD.

Yes, while not banned in the entire European Union (where it requires a warning label), it is completely banned in countries such as Norway and Iceland. In the U.S., California is implementing restrictions on its use in school meals starting in 2028.

Reported symptoms of sensitivity or intolerance to Red Dye #40 can include hyperactivity, irritability, headaches, migraines, and gastrointestinal upset. Allergic reactions like hives and swelling are possible but rare.

You can check a product's ingredient label for 'FD&C Red No. 40', 'Allura Red AC', or 'Red 40'. It's most commonly found in brightly colored processed foods like candy, cereal, and drinks.

Natural food colorings derived from sources like beets, paprika, and turmeric are generally considered safer and are used by many manufacturers as an alternative to synthetic dyes. Choosing products with these natural alternatives can help reduce exposure to artificial dyes.

While Red Dye #40 is not classified as a carcinogen, it has been found to contain trace amounts of known carcinogens like benzidine. Recent animal studies have also raised concerns about DNA damage and colonic inflammation, though human studies are still needed.

The FDA currently considers Red Dye #40 safe for consumption within regulated limits. However, it acknowledges that some children may be sensitive and is continuing to monitor new research findings.