Nutrition Diet: Is erythrosine a natural or synthetic dye?

October 8, 2025 •

4 min read

First synthesized in 1876, FD&C Red No. 3 is a synthetic dye commonly known as erythrosine. This raises a key question for health-conscious consumers: is erythrosine a natural or synthetic dye?

Quick Summary

Erythrosine, also known as FD&C Red No. 3, is a synthetic, petroleum-derived food colorant that provides a cherry-pink hue to products. Due to various health concerns, its use is heavily regulated and recently banned in food and ingested drugs in the US.

Key Points

Synthetic Origin: Erythrosine is a synthetic dye, manufactured in a laboratory from petroleum-based chemicals, not from natural sources.
FD&C Red No. 3: It is formally known as FD&C Red No. 3 in the U.S. and E127 in Europe, and it imparts a cherry-pink or red color.
Regulatory Bans: Due to health concerns, the FDA has banned its use in food and ingested drugs in the US, with bans taking full effect in 2027 and 2028 respectively.
Health Concerns: Studies have raised concerns about erythrosine's potential effects on thyroid function, its links to hyperactivity in children, and carcinogenic effects in animal studies.
Nutritional Relevance: Growing consumer demand for 'clean label' products has accelerated the food industry's shift away from synthetic colorants towards natural alternatives derived from plants.
Alternative Dyes: Natural colorants, such as beetroot extract or anthocyanins, offer alternatives for achieving red and pink hues, aligning with consumer preferences for fewer artificial additives.

What is Erythrosine?

Erythrosine is an organoiodine compound, specifically a xanthene derivative, that creates a reddish-pink or cherry-red color. It has been extensively used as a food coloring, earning it designations like FD&C Red No. 3 in the United States and E127 in Europe. However, unlike natural food colorings derived from plants or minerals, erythrosine is created exclusively through chemical synthesis in a laboratory. Its chemical formula is $C{20}H{6}I{4}O{5}Na_{2}$.

The Manufacturing Process: A Synthetic Journey

The creation of erythrosine is a clear demonstration of its synthetic origin. It is a multi-step process that starts with petroleum-based compounds:

Step 1: Creating Fluorescein. The process begins with heating two chemicals, phthalic anhydride and resorcinol, to produce fluorescein, a yellowish-green compound.
Step 2: Iodination. The fluorescein is then treated with iodine and potassium iodide in a process called iodination. This reaction replaces certain hydrogen atoms with iodine atoms, resulting in the reddish-pink erythrosine compound.
Step 3: Stabilization. For commercial use, erythrosine is converted to its disodium salt form to improve its solubility in water, making it suitable for a wide range of food and beverage products.

This entire process, from raw materials to the final dye, takes place in a controlled laboratory or industrial setting, confirming that erythrosine has no natural counterpart.

History and Regulatory Restrictions

First synthesized in the late 19th century, erythrosine was initially used for textiles before its adoption in the food industry in the 1920s. The US Food and Drug Administration (FDA) first approved its use in food products in 1963. However, over the decades, evidence emerged suggesting potential health risks associated with synthetic dyes, including erythrosine.

Key regulatory milestones include:

1990: The FDA banned erythrosine for use in cosmetics and external drugs based on animal studies linking high doses to cancer in male rats.
Early 2020s: Growing concerns over its safety, fueled by continued research and public petitions, intensified.
October 2023: California passed a bill to ban FD&C Red No. 3 and several other additives in food products, effective January 2027.
January 2025: The FDA formally banned erythrosine from all food and ingested drugs. Manufacturers have until January 2027 (for food) and January 2028 (for drugs) to reformulate their products.

Health Concerns and Nutritional Context

Concerns over erythrosine's safety stem from various studies investigating its biological effects. While the evidence is complex and some studies are conflicting, the overall body of research has led to significant regulatory action.

Health issues potentially linked to erythrosine include:

Thyroid Function: Its high iodine content may interfere with thyroid hormone production and function, leading to potential thyroid issues.
Hyperactivity: Some studies, though mixed, have linked synthetic food dyes, including erythrosine, to increased hyperactivity and attention deficit disorders in children.
Potential Carcinogenicity: Animal studies have raised concerns about its carcinogenic properties at high doses, leading to regulatory bans based on the precautionary principle.
Hepatorenal Toxicity: Recent studies in animal models indicate that erythrosine can cause oxidative stress and damage to liver and kidney tissues in a dose-dependent manner.

For those focused on a clean and balanced nutrition diet, understanding the synthetic nature and associated risks of erythrosine is crucial for making informed food choices.

Common Sources of Erythrosine Before Regulatory Bans

Before recent bans took effect, erythrosine was a prevalent food coloring in many products, particularly those marketed to children. Common items included:

Confectionery: Hard candies, bubble gum, jelly beans, and other sweets.
Baked Goods: Cake-decorating gels, frostings, and snack cakes.
Desserts: Ice cream, popsicles, and other frozen novelties.
Processed Fruits: Maraschino cherries and canned fruits.
Snacks: Some fruit snacks and cereals.

Synthetic vs. Natural Dyes: A Comparison


Feature	Synthetic Dyes (e.g., Erythrosine)	Natural Dyes (e.g., Beetroot Extract)
Origin	Derived from petroleum and coal tar; chemically synthesized in a lab.	Extracted from plants, minerals, or insects; naturally occurring pigments.
Vibrancy & Shade	Provide very bright, consistent, and wide-ranging colors.	Tend to produce more muted, earthy tones with some color variability.
Stability	Highly stable and resistant to heat, light, and pH changes.	Generally less stable and can degrade when exposed to heat or light.
Cost	Less expensive for mass production due to efficient, large-scale manufacturing.	Often more expensive due to variable yields, extraction costs, and seasonality.
Regulatory Status	Subject to stringent certification and monitoring, with many facing restrictions or bans.	Typically considered safe and face fewer regulatory restrictions, though some require certification.
Health Perception	Often viewed with skepticism due to potential health risks, like hyperactivity or carcinogenicity.	Perceived as a safer, healthier alternative by many consumers.

Conclusion

The question, is erythrosine a natural or synthetic dye, can be answered unequivocally: it is a synthetic colorant. Derived from petroleum compounds and created in a laboratory, erythrosine has no natural origin. The increasing body of scientific evidence suggesting potential links to health concerns, from thyroid issues to behavioral effects in children, has driven significant regulatory action, including recent bans by the FDA and state governments. For individuals focusing on nutrition and clean eating, understanding the difference between synthetic dyes like erythrosine and their natural alternatives is a vital step in making informed dietary choices. As consumer demand for natural ingredients grows, many manufacturers are moving away from synthetic colorants toward plant-based options, shaping a cleaner and more transparent food landscape for the future. You can verify the regulatory status of FD&C Red No. 3 with the FDA's official color additives list.

Frequently Asked Questions

Concerns have been raised over erythrosine's safety due to animal studies linking it to thyroid issues and potential carcinogenicity at high doses, as well as a link to hyperactivity in children. This has led to restrictions and recent bans by regulatory bodies like the FDA.

The FDA banned FD&C Red No. 3 (erythrosine) in food and ingested drugs due to potential health risks, citing decades-old animal studies showing carcinogenic effects in male rats. This action followed years of regulatory debate and public petitions.

Historically, erythrosine was used in many products, such as maraschino cherries, frostings, sweets, ice pops, and some medications. With the recent FDA ban, manufacturers have a deadline to reformulate these products to remove the dye.

Yes, natural alternatives exist, such as beetroot extract, anthocyanins (from berries), and lycopene (from tomatoes). While these can be less stable and provide different shades, they are increasingly popular due to health-conscious consumer preferences.

On food labels in the U.S., erythrosine is identified as FD&C Red No. 3. In other parts of the world, it may be listed by its E-number, E127.

Yes, erythrosine (Red No. 3) is a different synthetic dye than Allura Red AC (Red No. 40). Both are artificial colorants, but they have distinct chemical compositions and are regulated separately.

Erythrosine was first synthesized in 1876 and later adopted by the food industry in the 1920s. Its use grew until increasing health concerns and regulatory actions in the late 20th and early 21st centuries led to bans and restrictions in many regions, including the recent U.S. ban.