also: FD&C Red No. 3 · Red 3 · Acid Red 51 · CI 45430
A cherry-pink synthetic dye made from iodine-rich fluorone, used to colour cocktail and candied cherries in the UK and EU.
Scan a barcode to check a food for erythrosine. NutraSafe Pro · £6.99/month · iPhone and Android
Fruit (in variable proportions: Peach, Pear, Pineapple, Grapes, Cherries (with colour Erythrosine)), Water, Sugar, Acidity Regulator: Citric Acid
Erythrosine carries a large amount of iodine by weight and at high doses disrupts thyroid hormone regulation in animal studies, leading to thyroid tumour development in male rats.
UK supermarket foods that declare E127: 24 of the 43,325 we checked (under 0.1%)
Counted by its code or its name in the ingredient list.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. Erythrosine carries a large amount of iodine by weight and at high doses disrupts thyroid hormone regulation in animal studies, leading to thyroid tumour development in male rats. The US FDA banned it in January 2025 under a law that prohibits any additive shown to cause cancer in animals, even where human relevance is disputed.
Erythrosine is an organoiodine compound derived from fluorone. It is a water-soluble synthetic dye that produces a vivid cherry-red to watermelon-pink colour. Iodine makes up approximately 58% of its molecular weight, which sets it apart from most other approved food dyes. It is also known as Red Dye No. 3 in the United States.
Erythrosine dissolves readily in water and binds to food proteins, giving preserved cherries their bright artificial red colour. Its high iodine content means that when ingested, erythrosine releases iodide into the bloodstream. At sufficient doses in animals, this elevated circulating iodide suppresses the conversion of thyroid hormone T4 into the active form T3 by inhibiting the enzyme 5'-deiodinase, which in turn drives the pituitary to release more thyroid-stimulating hormone (TSH) and chronically overstimulate the thyroid gland.
In the UK and EU, erythrosine is authorised only in cocktail cherries, candied cherries, glacé cherries, and bigarreaux cherries in syrup or in cocktails. It is not permitted in any other food category, including baking products, sweets, or sprinkles. Outside those permitted uses it is illegal to sell it as an edible colouring. On the label it appears as either 'E127' or 'Erythrosine' in the colour listing within the ingredients.
Male rats fed very high dietary concentrations of erythrosine over their lifetimes developed thyroid follicular adenomas (benign tumours) at rates significantly above controls. Female rats fed the same amounts did not show a significant increase. Regulators and independent reviewers agree the mechanism is indirect: the sustained elevation of TSH caused by suppressed T3 production chronically overstimulates thyroid cells, and at extreme doses this drives tumour formation.
Male Sprague-Dawley rats fed 4% dietary erythrosine from gestation through a 30-month lifetime developed a high incidence of thyroid follicular adenomas. Female rats at the same dose did not show a significant increase.
Short-term rat studies found erythrosine decreases hepatic 5'-deiodinase activity, reducing conversion of T4 to T3 and raising TSH, consistent with the indirect hormonal mechanism for thyroid tumour development.
EFSA concluded that the thyroid tumours in rats are secondary to the hormonal effects of erythrosine and are not due to any genotoxic activity. EFSA considered the rat findings of limited relevance to humans, given differences in thyroid physiology between rats and people.
A controlled human study gave healthy men doses of 20, 60, or 200 mg of erythrosine daily for 14 days. At 200 mg per day, basal TSH rose and the TSH response to stimulation increased significantly. No effects were detected at 60 mg per day or below. EFSA and JECFA used the 60 mg per day no-effect level, with a tenfold safety factor, to set the ADI of 0.1 mg per kilogram of body weight per day.
In 30 healthy men, 200 mg erythrosine daily for 14 days raised basal serum TSH from 1.7 to 2.2 microU/ml and increased peak TSH response significantly. Doses of 20 and 60 mg daily produced no significant changes in thyroid hormone measures.
JECFA set an ADI of 0-0.1 mg per kg body weight per day, based on the human no-observed-effect level of 60 mg per person per day, applying a safety factor of 10. Human data were prioritised over the rat findings given species differences in thyroid physiology.
In January 2025 the US FDA revoked authorisation for erythrosine in food and ingested drugs. The legal trigger was the Delaney Clause, a 1958 US law requiring the FDA to ban any additive shown to cause cancer in humans or animals, regardless of dose or mechanism. The FDA acknowledged it had no direct evidence of cancer in people and noted the animal mechanism may not apply to humans, but the Clause left no discretion once the animal tumour finding was established.
The FDA revoked authorisation for FD&C Red No. 3 (erythrosine) in food and ingested drugs on 15 January 2025, citing the Delaney Clause requirement following the established finding of thyroid tumours in male rats. Compliance dates are January 2027 for food and January 2028 for ingested drugs.
Recent animal research found that erythrosine at doses including the ADI level, given daily for 28 days, produced measurable changes in rat brain tissue: suppressed antioxidant enzyme activity, increased lipid peroxidation, DNA strand damage in a comet assay, and abnormal brain cell appearance under microscopy. These are laboratory findings in rats, not human data, and the doses used are far above what typical consumption of the permitted foods would deliver.
Wistar rats given erythrosine at one quarter, one half, or the full ADI dose daily for 28 days showed suppressed antioxidant enzyme activity (CAT, SOD, GST), increased lipid peroxidation, reduced acetylcholinesterase activity, and DNA damage in the brain at all doses tested including the ADI level.
Standard mutagenicity tests, reviewed repeatedly by JECFA and EFSA, found erythrosine to be non-genotoxic. Both bodies concluded the thyroid tumours in rats arose through an indirect hormonal mechanism rather than direct DNA damage. However, more recent in vitro and animal work using sensitive DNA-damage assays has found genotoxic signals at higher doses, creating some scientific disagreement that has not yet been resolved.
JECFA reviewed comprehensive mutagenicity data and concluded erythrosine is not genotoxic, with the rat thyroid tumours arising through hormonal overstimulation rather than direct mutagenic action.
An in vitro study using Allium cepa root meristematic cells found erythrosine induced cytotoxicity, mitotic abnormalities, and DNA damage signals, raising questions about genotoxic potential at higher concentrations.
People with thyroid conditions or iodine sensitivity should be aware that cocktail cherries and candied cherries coloured with E127 carry a concentrated iodine-containing compound. Look for 'E127' or 'Erythrosine' in the colour section of the ingredients list on jars of cocktail or maraschino cherries.
The regulatory picture for erythrosine is split along continental lines. The US FDA banned it in January 2025 because a 1958 law requires prohibition whenever an additive causes cancer in any animal at any dose, even if the mechanism does not apply to humans. The EU and UK set a very tight permitted use back in 1994, restricted to a handful of cherry products, and have not issued a ban. EFSA's view, last formally stated in 2011, is that the rat thyroid tumour mechanism is indirect and unlikely to translate to humans at realistic food exposures. More recent animal studies, including a 2025 paper finding DNA damage in rat brain tissue at doses equivalent to the ADI, add new findings that have not yet been through full regulatory review. The science has not converged, and the two largest food regulators in the world have landed in different places with the same underlying data.
No. E127 remains authorised in the UK as of June 2026, but its permitted uses are extremely limited: it can only be used in cocktail cherries, candied cherries, glacé cherries, and bigarreaux cherries in syrup or cocktails. It is not permitted in any other food, including baking sprinkles, sweets, or cake decorations. The US FDA banned it in January 2025; the UK and EU have not followed.
The US invoked the Delaney Clause, a 1958 law that obliges the FDA to ban any additive shown to cause cancer in any animal at any dose. Male rats fed very high concentrations of erythrosine developed thyroid tumours in long-term studies. The FDA acknowledged these findings are likely due to a rat-specific hormonal mechanism that does not apply to humans, but the law left no room for that distinction. The EU and UK use risk-based assessment frameworks that allow regulators to weigh whether animal findings translate to human risk, and both considered the restricted, low-exposure cherry-product uses to remain within acceptable limits.
In the UK, E127 is legally permitted only in cocktail cherries, candied cherries, glacé cherries, and bigarreaux cherries in syrup or cocktails. Imported products from countries with broader permissions (such as the US before 2027) may contain it in other foods, but selling those products in the UK would breach food law. Check the colour declaration in the ingredients list: it appears as 'E127' or 'Erythrosine'.
Yes. Erythrosine is a fully synthetic compound, not derived from animals or animal products. It is suitable for vegans and vegetarians.
Last reviewed: 20 June 2026
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