What Is Red 40

In 2011 , the FDA said that synthetic color additives had no adverse effects. However, research has since shown that they can cause ADHD symptoms and that some children are particularly sensitive to their effects.

What is Red No. 40?

Red no. 40 is a synthetic dye that’s used in a variety of foods. It’s one of nine synthetic dyes that the U.S. Food and Drug Administration (FDA) has approved for human consumption. It’s also currently approved by the European Food and Safety Authority (EFSA).

The full name of this dye is FD and C red no. 40. It’s considered a color additive. This describes any substance that adds color to food, cosmetics, and drugs.

What Is Red 40 Made of?

Red no. 40 consists of a chemical compound called Allura red AC. This is a naphthalene sulfonic acid.

Allura red AC typically comes in the form of a dark red powder or small granules. You can dissolve it in water, 50-percent-alcohol solutions, glycerol, and propylene glycol.

When it’s heated to extreme temperatures — to the point where it molecularly decomposes — it emits toxic fumes composed of nitrogen and sulfur oxides. Luckily, you should never reach such extreme temperatures when using this substance in food production.

There are also non-colored components of the dye. These are typically sodium chloride and sodium sulfate.

How Is Red 40 Made?

Red no. 40 is a synthetic food dye. This means that it doesn’t occur anywhere in nature and needs to be created through man-made processes.

Specifically, it’s the product of a chemical reaction that involves two different types of sulphonic acids. This reaction couples a type of toluene sulphonic acid with a different type of naphthalene sulphonic acid.

There are a number of products that stem from this reaction. Allura red AC is associated with the sodium salt that’s produced. Calcium and potassium salts are also created and are considered safe components of the reaction.

Over 30 companies currently produce this dye.

What Is Red 40 Used For?

The purpose of red no. 40 — and all synthetic dyes — is to create distinct, uniform colors in consumable products. They’re great for fun, eye-catching foods like cake mixes, frostings, and soft drinks. They’re commonly added by large-scale food manufacturers but can also be used in home cooking.

Color additives can also help consumers identify the flavors of consumable goods. For example, purple coloring usually implies a grape flavor, and yellow usually implies lemon. Using red no. 40 could imply some kind of cherry, strawberry, or raspberry flavor. Synthetic dyes can blend together easily, which allows you to get a wide variety of hues.

The FDA has to approve every type of dye before it can be used in consumable goods. Synthetic dyes need to go through the approval process for every new use. The FDA specifies exactly how the dyes can be used and the amount that’s allowed.

Red no. 40 is approved to add color to a wide range of food products. These include:

  • Gelatins
  • Puddings
  • Beverages — both alcoholic and non-alcoholic
  • Dairy products
  • Frostings
  • Fruits
  • Bakery products
  • Jams
  • Condiments
  • Meat and poultry

Allura red AC can also be used to color arts and crafts supplies like crayons, pens, and markers.

Is Red 40 Safe?

The FDA has ruled that red no. 40 is safe for public consumption. They reviewed the dye as recently as 2019.

There’s some controversy about the ruling that this dye is completely safe, though. People are petitioning the FDA to at least include a warning label in all foods that contain this synthetic dye.

The reason for this protest is that preliminary evidence indicates that consuming certain synthetic dyes might make symptoms of attention deficit hyper activity disorder (ADHD) worse. The synthetic dyes that could be to blame include:

To date, studies have only shown very minor effects from these dyes. There are also some problems with most of these studies, calling into question the quality of the data. Problems include things like studying so many additives at one time that it’s impossible to pin the effects on a particular substance.

However, overall, there does seem to be conclusive evidence that consuming certain synthetic dyes, like red no. 40, can increase hyperactivity — and possibly irritability — in susceptible children. Only a small percentage of people are affected. Most of these people are children who are diagnosed with ADHD and seem to be particularly sensitive to these additives.

To be clear, there’s no evidence that consuming these dyes actually causes ADHD, but they might make certain symptoms worse.

The FDA, however, needs more evidence before they’re willing to add a warning label to foods that contain red no. 40.

Tips for Avoiding Synthetic Dyes

Despite their relative safety, some families may want to avoid synthetic dyes. This is particularly likely if you believe that your child is sensitive to food dyes.

There are a few tips that you should keep in mind to help you with this process.

  • Carefully read food labels to see if particular synthetic dyes are listed.
  • Avoid processed foods.
  • Carefully research fast food places before making any purchases — many include synthetic dyes in ways that you wouldn’t necessarily anticipate.
  • Stick to fresh foods like fruits and vegetables at snack time.

You can try eliminating all foods with synthetic dyes from your child’s diet for at least two weeks to see if they’re particularly sensitive. You should carefully observe and record their behavior, though, for two weeks prior to this trial period. Continue doing this throughout the trial period to see if eliminating synthetic dyes affects their behavior in any way.

How Is Red 40 Regulated?

Synthetic dyes are regulated in a very specific way by the FDA. Manufacturers have to undergo a process called batch certification. This means that the FDA needs to test a subset of samples from every new batch that a company produces.

This is different from how they regulate natural dyes. Naturally occurring dyes need to be approved for use in food once. Then, they can be used as needed.

There are a number of factors that the FDA considers when evaluating a synthetic dye either for first-time approval or for a new use. These considerations include:

  • Short and long-term effects of consuming the dye
  • The composition of the substance
  • Its properties
  • Its stability
  • The likely amount that people will consume or otherwise encounter
  • The quality and availability of analytical methods needed to determine the purity and amount of the dye
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Like all synthetic dyes, red no. 40 needs to be listed by name on food labels.

Show Sources

ADDitude: “The Truth About Food Dyes and ADHD: What Science Tell Us.”

Children and Adults with Attention Deficit/Hyperactivity Disorder: “Do Artificial Food Colors Cause ADHD Symptoms.”

Food and Drug Administration: “Color Additives Questions and Answers for Consumers.”

Michigan State University: “101 Series: Food Dyes.”

PubChem: “Allura Red AC.”

Is the Food Dye Red 40 Dangerous to Your Health?

Homemade Gourmet Donuts with colorful fruity Cereal on Top

While some people are skeptical of food dyes, specifically Red No. 40, formally known as Allura Red AC, the FDA deems the additive to be safe and regulates its use in food.

Still, other organizations, including the Center for Science in the Public Interest (CSPI) consider Red Dye 40 potentially harmful (particularly to children). One thing experts can agree on is that Red Dye 40 has been highly controversial throughout the years.

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The Food and Drug Administration deems Red Dye 40 to be safe and regulates its use in food; however, other organizations, such as the Center for Science in the Public Interest, believe it to be carcinogenic.

What Is Red Dye 40?

As a color additive, Red Dye 40 is used by manufacturers to give products — including food, drugs and cosmetics — a certain appearance, according to the FDA. When it comes to food, color additives can either enhance the food’s natural color, give color to a food that doesn’t have color or help give a flavored food a certain identity.

For example, think of the last time you ate something that was strawberry-flavored, such as candy or yogurt. It might not have had any real strawberry in it (or not enough to give it an enticing red color), so the manufacturer used Red No. 40 to turn it pinkish red to help you associate it with strawberries.

Red Dye, like most artificial dyes, is derived from petroleum, per the CSPI.

Foods With Red Dye 40

Red Dye 40 can be found in a multitude of foods It is classified as a synthetic or artificial coloring rather than a natural coloring, which are derived from plants, animals or minerals.

The following foods are some of the more common sources of Red Dye 40, according to the FDA:

  • Cereal
  • Beverages
  • Gelatins
  • Puddings
  • Dairy products
  • Sweets and baked goods

Red Dye 40 is eaten most often by children and, as such, it shows up in a lot of children’s foods (think flavored milks and yogurts, colorful desserts and snacks and saccharine drinks).

Children ages two to five ate the most Red Dye 40 per day, according to a June 2017 study in ​Food Additives & Contaminants.​ Two- to five-year-olds had an average daily intake of Red Dye 40 at 0.0045 milligrams per pound (0.01 milligrams per kilogram) of body weight, while adults had the lowest at 0.0014 milligrams per pound (0.003 milligrams per kilogram) of body weight.

Red 40 is generally considered vegan, according to the Vegetarian Resource Group, which lists artificial colors as “typically synthetic.”

How to Identify Red Dye 40 in Foods

You can start by reading food labels: The FDA requires Red Dye 40 to be listed on the ingredients list of food products that use the coloring. The ingredient may be listed under one of the following names:

  • Red 40
  • Red 40 Lake
  • FD&C Red No. 40
  • FD&C Red No. 40 Aluminum Lake
  • Allura Red AC
  • CI Food Red 17
  • INS No. 129
  • E129

2 Potential Dangers of Red Dye 40

The CSPI, one of the largest opponents of the synthetic red dye, has been working to pressure the FDA to ban food dye in commercially prepared food since 2008, according to Harvard Health Publishing. The group has several concerns:

1. Allergies and Red Dye 40

It’s possible that Red Dye 40 is an allergen for some groups of people, though it’s often very difficult to identify the cause of an allergic reaction in these cases, according to a September 2017 review in ​Food Chemistry​.

It is especially difficult to associate an allergy with Red Dye 40 specifically because the additive is often used in concert with many others. Still, “the dye causes hypersensitivity (allergy-like) reactions in a small number of consumers,” according to a CSPI report.

2. ADHD and Red Dye 40

The FDA acknowledges that while most children don’t experience adverse behavioral effects when consuming foods that contain Red Dye 40, there’s some evidence that suggests some children may be sensitive to the ingredient.

Indeed, an estimated 8 percent of children living with Attention Deficit-Hyperactive Disorder (ADHD) in the U.S., U.K., Australia and Canada may have behavioral symptoms tied to synthetic food colors, per a January 2012 review of 34 studies published in the ​Journal of the American Academy of Child and Adolescent Psychiatry.

Research suggests that artificial dyes like Red Dye 40 may cause these types of behavioral conditions in children, which include excess inattention, impulsivity and hyperactivity, because they can cause chemical changes in the brain, according to a May 2013 review in ​Nutrition Review.

Several studies on children with ADHD, like the January 2012 review in the ​Journal of the American Academy of Child and Adolescent Psychiatry,​ found that when synthetic food dyes were restricted from their diets, these children showed significant improvements in their symptoms.

Still, the science isn’t so clear-cut as these improvements were found mainly in children with general food sensitivities or intolerances, according to an April 2011 study in ​Clinical Pediatrics​.

Is Red 40 Safe?

The answer to this question really depends on who you ask. The FDA considers the artificial dye safe in the amounts it regulates, though it does acknowledge that some children may be sensitive to the ingredient and experience side effects.

On the other hand, the CSPI suggests that Red 40 can lead to adverse reactions and trigger ADHD symptoms in children.

For now, at least, it seems that it’s up to the consumer to decide whether Red 40 is safe. While the official jury is still out (depending on who you consider the official jury), manufacturers have made changes to address concerns around synthetic food coloring.

In 2015, for example, General Mills announced its commitment to remove all artificial colorings from its cereals. The company said it would transition to using fruit and vegetable juice as well as spice extracts to color its cereals. Similarly, Kraft also nixed artificial dyes from its iconic yellow macaroni and cheese mixture in 2015, CBS News reported.

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It’s worth noting, perhaps, that these brands made these changes only after a study found that many name brand foods, including those owned by General Mills and Kraft, contained dyes in amounts higher than the levels demonstrated in some clinical trials to impair some children’s behavior, according to the CSPI.

Is there a link between red dye 40 and ADHD?

Red dye 40 is a synthetic food dye. This and other dyes may worsen the symptoms of attention deficit hyperactivity disorder (ADHD) in some children with the condition, but more research is needed.

Researchers have extensively looked at the connection between diet and ADHD. Although data suggest that food dyes increase ADHD symptoms, they only seem to do so by a small amount. However, some children may be more sensitive to their effects than others.

Keep reading to learn about what red dye 40 is, how to find it on food labels, and how it can affect children with ADHD.

A container of frosting, one of which is red.

Red dye 40 is a commonly used synthetic food dye made from petroleum.

It is one of nine certified color additives that the Food and Drug Administration (FDA) has approved for use in food and beverages. Manufacturers use synthetic color additives more often than natural options because they provide a more uniform color, do not add unwanted flavors, and are generally cheaper.

Food manufacturers can only use synthetic additives that the FDA has certified. Natural color additives, which are pigments from vegetables, minerals, and animals, are exempt from certification. However, the FDA must still approve them for use.

Red dye 40 is one of the most commonly used color additives. It is present in many foods and beverages, including:

  • energy and sports drinks
  • soda
  • protein powders
  • cereals
  • dairy products
  • gelatins
  • candy
  • chewing gum
  • confections

A person can identify whether a food or beverage contains red dye 40 by reading the ingredients list. Although manufacturers are not required to disclose the amount of a listed ingredient present in the product, they must list the ingredients by weight.

The ingredients labels on packaged foods and drinks may sometimes list red dye 40 by one of its other names, which include:

  • Allura Red AC
  • Red 40
  • Red 40 Lake
  • FD&C Red no. 40 Aluminum Lake
  • FD&C Red no. 40
  • E129
  • CI Food Red 17
  • INS no. 129

Research in both animals and humans has shown synthetic color additives such as red dye 40 to have links to ADHD symptoms and other neurobehavioral conditions.

In 2011 , the FDA said that synthetic color additives had no adverse effects. However, research has since shown that they can cause ADHD symptoms and that some children are particularly sensitive to their effects.

According to a 2021 report from the state of California, research does indicate that children who consume synthetic food dyes, including red dye 40, can experience hyperactivity and other neurobehavioral issues.

Experts believe that red dye 40 and other synthetic color additives may cause behavioral changes due to:

  • a depletion of minerals that play a role in growth and development, including zinc and iron
  • chemical changes in the brain
  • hypersensitivity, which causes allergic reactions such as inflammation

Many studies on synthetic color additives look at red dye 40. Although the data vary, the majority of studies report at least some connection between color additives and ADHD symptoms.

Sensitivity to food dyes varies from one person to another, but most research has focused on children. Adverse effects can occur in children with and without preexisting behavioral conditions, such as ADHD.

Hyperactivity symptoms can include :

  • constant fidgeting
  • an inability to concentrate
  • being unable to sit still
  • excessive movement
  • an inability to wait their turn
  • interrupting conversations
  • little or no sense of danger

In adults, hyperactivity symptoms may also include restlessness and excessive talking.

Research indicates that hyperactivity in some children may increase due to exposure to synthetic food dyes, including red dye 40.

People often assume that sugar consumption, especially in children, can lead to an increase in ADHD symptoms, such as hyperactivity and inattention.

However, there are mixed study findings on whether sugar and ADHD are related.

According to a 2019 study in the Journal of Affective Disorders, there is some evidence that a diet high in refined sugar and saturated fat increases the risk of ADHD. However, the authors say that the current evidence, which relies primarily on observational studies, is weak and that more research is necessary.

A 2020 study in Complementary Therapies in Medicine suggests that there may be a relationship between sugar consumption and ADHD symptoms. However, another 2019 study found that there was no link between sucrose, a type of sugar, and ADHD incidence in children.

Although there is a need for more studies to determine the effects of sugar on ADHD symptoms, most research suggests that there is a link between food dyes and hyperactivity. This is especially true of the widely studied food dyes, including red no. 3, red dye 40, and yellow no. 5.

Red dye 40 is a synthetic food dye made from petroleum. Research has shown that it is linked to certain ADHD symptoms, such as hyperactivity, and may also cause other neurobehavioral effects in children.

People can check for red dye 40 on food labels if they wish to limit their intake. It is important to note that it may go by other names, including Allura Red AC, Red 40, Red 40 Lake, FD&C Red no. 40 Aluminium Lake, and FD&C Red no. 40.

Last medically reviewed on February 25, 2022

  • Food Allergy
  • ADHD / ADD
  • Nutrition / Diet
  • Pediatrics / Children’s Health

How we reviewed this article:

Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

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  • Batada, A., et al. (2016). Prevalence of artificial food colors in grocery store products marketed to children [Abstract].
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    https://www.fda.gov/food/food-additives-petitions/color-additives-questions-and-answers-consumers
  • Del-Ponte, B., et al. (2019). Dietary patterns and attention deficit/hyperactivity disorder (ADHD): a systematic review and meta-analysis.
    https://www.sciencedirect.com/science/article/abs/pii/S0965229919320540?via%3Dihub
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    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6193136/
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Alex Koliada, PhD

Alex Koliada, PhD

Alex Koliada, PhD, is a well-known doctor. He is famous for his studies of ageing, genetics and other medical conditions. He works at the Institute of Food Biotechnology and Genomics NAS of Ukraine. His scientific researches are printed by the most reputable international magazines. Some of his works are: Differences in the gut Firmicutes to Bacteroidetes ratio across age groups in healthy Ukrainian population [BiomedCentral.com]; Mating status affects Drosophila lifespan, metabolism and antioxidant system [Science Direct]; Anise Hyssop Agastache foeniculum Increases Lifespan, Stress Resistance, and Metabolism by Affecting Free Radical Processes in Drosophila [Frontiersin].
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