E127: Erythrosine

E127: Erythrosine

What is E127 (Erythrosine)?

Erythrosine (E127), also known as FD&C Red No. 3 or Cherry Red, is a synthetic cherry-pink iodine-containing xanthene dye used as a food colorant. Unlike most synthetic food dyes which are azo compounds, erythrosine belongs to the xanthene class of dyes. It contains four iodine atoms per molecule, making it unique among food colorings and raising specific thyroid-related health concerns. It has a distinctive cherry-red shade used in certain specific food applications.

Source and Production

Erythrosine is produced synthetically through a specific chemical process:

1. Base Compound: Fluorescein serves as the starting material 2. Iodination: Four iodine atoms are introduced onto the fluorescein molecule 3. Saponification: The ester is hydrolyzed under alkaline conditions 4. Salt Formation: The disodium salt form is most commonly used in food 5. Purification: Recrystallization produces food-grade quality material

The high iodine content (approximately 58% by weight) distinguishes erythrosine from other food dyes and contributes to its unique biological activity.

Common Uses in Food

E127 is used in relatively limited food applications due to its specific color profile:

• Cocktail and maraschino cherries
• Canned fruit products
• Certain confectionery and sweets
• Some cake decorating products
• Glacé cherries
• Certain medications (tablets and capsules)
• Dental disclosing tablets (highlights plaque)
• Some red-colored sweets

Health and Safety

Thyroid Effects

The most significant concern with erythrosine is its effect on the thyroid gland. Because the dye contains iodine:

• High doses in animal studies caused thyroid follicular cell adenomas (benign tumors)
• This led the US FDA to ban erythrosine from cosmetics and externally applied drugs in 1990
• The iodine released from erythrosine metabolism can affect thyroid hormone levels
• Individuals with thyroid conditions or iodine sensitivity may be particularly at risk

Other Health Concerns

• Photosensitivity: Can cause light sensitivity reactions in some people
• Neurobehavioral effects: Some early research suggested a link to hyperactivity, though less robustly than the azo dyes
• Chromosome effects: In vitro studies showed some genotoxic potential at high concentrations

Regulatory Status

• European Union: Permitted as E127, primarily in cocktail cherries and canned cherries in syrup
• United States: The FDA issued an order on January 15, 2025 revoking authorization for FD&C Red No. 3 in food, including dietary supplements, and ingested drugs. Food manufacturers have until January 15, 2027 to reformulate; products made before the deadline may remain on sale. The FDA says the order was required by the Delaney Clause based on high-dose effects in male rats, and that available evidence does not show the same effect in humans. See the FDA's current Red No. 3 guidance.
• ADI: 0.1 mg/kg body weight/day (JECFA) — one of the lower ADIs for food colorings

Identification on Labels

Erythrosine may be listed as:

• E127
• Erythrosine
• FD&C Red No. 3
• Red 3
• C.I. 45430
• Food Red 14

Alternatives

Natural alternatives with similar red/cherry hues:

• Cochineal/Carmine (E120): Natural insect-derived red dye
• Betanin (E162): Beetroot-derived red
• Anthocyanins (E163): Berry-derived red-purple pigments
• Cherry/fruit juice concentrates: Natural coloring from fruit itself

Conclusion

E127 (erythrosine) is a synthetic, iodine-containing red dye. Its authorization depends on the country and product: the FDA revoked U.S. food-use authorization in 2025, with the food reformulation deadline set for January 15, 2027, while some uses remain authorized elsewhere. The FDA describes its action as a legal requirement under the Delaney Clause and says available evidence does not show the rat-specific effect in humans. Check the current rules for your country and product type.