What Is Red 40? Ingredients, Side Effects, and Regulation

That bright cherry-red color in your sports drink or candy likely comes from a synthetic dye called Red 40. It’s one of the most widely used food colorings in the United States, but its safety has become a subject of debate.

Common name: FD&C Red 40 (US) or E129 (EU) ·
Source: petroleum distillates and coal tar ·
Annual US consumption estimate: over 4.5 million pounds ·
Common uses: candy, soda, dairy, cereals, condiments ·
Regulatory status in UK: not banned, but warning labels required on some products

What is Red 40?

Red 40, also known as Allura Red AC, is a synthetic azo dye that gives foods and drinks a bright cherry-red color. It’s one of the most common artificial colorings in the American food supply, showing up in everything from candy and sports drinks to cereals and condiments. The WebMD (health information publisher) notes that Red No. 40 is a synthetic color additive regulated by the FDA, and manufacturers must undergo batch certification to use it.

It holds two official designations: FD&C Red 40 in the United States and E129 in the European Union. Chemically, it belongs to the azo dye class — molecules characterized by nitrogen-nitrogen double bonds that produce vivid colors. The GoodRx (pharmacy health service) states that Red No. 40 is one of nine color additives certified by the FDA for use in food.

The implication: Red 40 is thoroughly regulated on paper but rarely absent from processed foods. Its approval in 1971 set the stage for decades of widespread use that the public is now questioning.

What is Red 40 made of?

Red 40 is produced entirely from petroleum-based raw materials. Specifically, manufacturers extract aromatic hydrocarbons from crude oil and coal tar, then chemically transform them through a series of reactions that produce the vivid red sodium salt known as Allura Red AC. Its chemical formula is C₁₈H₁₄N₂Na₂O₈S₂.

• Petroleum and coal tar origins: The dye starts with petroleum distillates — the same raw materials used to produce gasoline and plastics. Through sulfonation and diazotization, these become the azo compound that binds to food.
• Not from bugs: A common misconception is that Red 40 comes from crushed insects. That’s a different red dye — carmine (E120) — which is derived from cochineal beetles. Red 40 is fully synthetic.

What this means: The “natural vs. synthetic” debate around Red 40 isn’t really a debate — it’s unambiguously artificial. For consumers seeking naturally derived colors, the distinction from carmine matters a great deal for both ethical and dietary reasons.

What does Red 40 do to the body?

This is the question driving most consumer concern, and the answer depends on which regulatory body you ask.

Digestive tract and inflammation

A 2023 peer-reviewed study published in PubMed Central (National Institutes of Health database) found that Red 40, “acting as a foreign substance, induces a subtle and low-grade inflammatory response specific to the colon and rectum” in mice. The same study reported that the dye caused DNA damage in colon cells and disrupted the gut microbiome. The FEPBlue (federal employee health insurer) notes that studies suggest Red No. 40 may cause gut inflammation and disrupt beneficial bacteria.

Hyperactivity in children

The most well-known human effect is a link to hyperactivity, particularly in children with ADHD. The landmark 2007 “Southampton study” commissioned by the UK Food Standards Agency found that mixtures of certain artificial colors — including Red 40 — were associated with increased hyperactive behavior in children. This research directly led to the European Union requiring warning labels on products containing Red 40 from 2010 onward. The MD Anderson Cancer Center (National Cancer Institute-designated center) reports that red dye 40 has been linked to concerns about hyperactivity and neurobehavioral effects in children.

FDA position

The Wikipedia notes that the FDA considered Red No. 40 safe for use in food, drugs, and cosmetics. The FDA has maintained that Red 40 is safe at current intake levels based on its existing body of research — a position that diverges from the European approach.

The trade-off: The US regulatory system requires proof of harm before restriction, while the EU system applies the precautionary principle — requiring warning labels even when harm isn’t conclusively proven. This philosophical gap explains why the same dye is treated differently in New York versus London.

“The synthetic dye Red 40, acting as a foreign substance, induces a subtle and low-grade inflammatory response specific to the colon and rectum.”

— 2023 PMC study authors (Zhang et al.), PubMed Central (National Institutes of Health database)

“The FDA considered Red No. 40 safe for use in food, drugs, and cosmetics.”

— Wikipedia (citing FDA regulatory records)

Is red dye 40 banned in the UK?

No, Red 40 is not banned in the United Kingdom. After Brexit, the UK retained the EU’s regulatory framework for food additives, including the warning label requirement for products containing Red 40. The Pederson’s Farms (specialty food producer) reports that the European Union allows the dye but requires warning labeling for certain foods containing it. This requirement did not change after the UK left the EU. The warning states that the color “may have an adverse effect on activity and attention in children.”

The practical result: You can buy Fanta, Skittles, and other dyed products in British supermarkets — they just carry a small text warning on the package. It’s a compromise that keeps the products on shelves while putting parents on notice.

What is Red 40 called in Europe?

In the European Union and the United Kingdom, Red 40 is listed on ingredient labels as E129. The “E” stands for “European” and indicates the additive has been approved by the European Food Safety Authority (EFSA). The substance’s chemical name — Allura Red AC — is also recognized globally.

• E129 designation: This is the number you’ll find on ingredient lists for EU-manufactured products. It’s part of the E-number system that covers all approved food additives.
• Allura Red AC: This is the chemical name used in scientific literature and regulatory documents worldwide.

The implication: If you’re an American traveler in Europe checking a candy wrapper, you need to look for E129 — not “Red 40.” The ingredient may be the same, but the labeling system is entirely different.

Where is Red 40 found in food?

Red 40 appears in an astonishing range of processed foods. The WebMD (health information publisher) notes that Red 40 is commonly discussed in relation to foods, beverages, and processed snacks that use synthetic coloring to create a bright red or pink appearance.

Common product categories with Red 40

• Candy and sweets: Skittles, M&Ms, Starburst, Twizzlers, Peeps, jelly beans
• Beverages: Fruit punches, sports drinks, sodas (especially fruit flavors), powdered drink mixes
• Dairy products: Flavored yogurts, ice cream, popsicles, pudding
• Cereals and snacks: Froot Loops, Lucky Charms, Pop-Tarts, fruit snacks
• Condiments and sauces: Ketchup (some brands), barbecue sauce, hot sauce, salad dressings

Does ketchup have Red 40? Some brands do, though the major ketchup manufacturers (Heinz, Hunt’s, French’s) primarily use red dye in their “organic” varieties or specialty flavors. Standard ketchup’s red color comes from tomatoes, but some budget or novelty condiments add Red 40 for a more uniform hue.

Why this matters: Avoiding Red 40 requires reading ingredients on nearly every processed item. It’s not just candy — it’s your kids’ yogurt, your weekday cereal, and sometimes even the sauce on your hot dog.

Why are people avoiding Red 40?

Consumer concern around Red 40 has grown significantly over the past decade, driven by three primary factors.

Health concerns

• Hyperactivity: The Southampton study and subsequent research have created a persistent public perception that artificial dyes worsen children’s behavior. The MD Anderson Cancer Center (National Cancer Institute-designated center) reports that red dye 40 has been linked to concerns about hyperactivity and neurobehavioral effects in children.
• Potential DNA damage: The 2023 mouse study from PubMed Central (National Institutes of Health database) showing DNA damage in colon cells added a new dimension to the safety debate.
• Regulatory uncertainty: The Cleveland Clinic (academic medical center) reported in 2025 that the FDA planned steps to phase out red dye 40 and several other synthetic dyes by the end of 2026, signaling a potential shift in US policy.

Consumer preference for natural alternatives

The clean-label movement has pushed many food manufacturers to reformulate products with natural colorants like beet juice, turmeric, and paprika extract. The NBC News (major network news) reported that many food and beverage makers already had recipes without Red No. 3 because it was prohibited in the EU and elsewhere.

Specifications table: Red 40 at a glance

Seven data points, one pattern: Red 40 is a chemically simple molecule caught between very different regulatory philosophies.

The catch: The same chemical is regulated as safe by the FDA, conditionally permitted with warnings by the EU, and voluntarily phased out by many brands — leaving consumers to navigate conflicting signals.

Confirmed vs. Unconfirmed: What the evidence actually shows

Confirmed facts about Red 40

• Red 40 is a synthetic azo dye from petroleum (WebMD (health information publisher)).
• It is used widely in processed foods in the US, UK, and EU (WebMD (health information publisher)).
• It is not banned in the UK or EU (Pederson’s Farms (specialty food producer)).
• Red 40 requires batch certification by the FDA (WebMD (health information publisher)).
• A 2023 study found it induced DNA damage and colon inflammation in mice (PubMed Central (National Institutes of Health database)).

What remains unclear

• Whether Red 40 causes significant health harm to humans at typical intake is still debated.
• Whether the DNA damage observed in mice translates to humans at dietary levels is not yet confirmed.
• Whether the FDA’s reported 2026 phase-out plan will apply to Red 40 or only Red 3 remains uncertain.

Summary: What the Red 40 debate actually means for you

Red 40 sits at the center of a growing divide between what regulators permit and what consumers trust. The FDA still says it’s safe; the EU says it’s safe enough to sell but risky enough to warn about; and a 2023 animal study raised a DNA-damage flag that science hasn’t resolved yet. For American shoppers, the choice is clear: read ingredient labels carefully, or switch to products colored with natural alternatives like beet juice and turmeric. For European shoppers, the same choice applies — but at least your package will tell you if the dye is inside.

Related reading: **What Does Ozempic Do? Weight Loss, Results & Side Effects**

For a closer look at how different countries approach this controversial dye, see this detailed overview of Red 40 side effects and bans.

Frequently asked questions