Indigo Carmine | whatsinit

About

What it is and where it shows up.

Indigo Carmine (E132) is a synthetic indigoid blue food dye derived from indigo, used to impart a deep blue or blue-green colour to foods, beverages, confectionery, and pharmaceutical products. It is widely employed across the food, textile, pharmaceutical, and medical industries.

Safety summary

The regulatory and scientific consensus.

EFSA and JECFA have established an ADI of 5 mg/kg body weight per day; EFSA confirmed in its 2023 follow-up that there is no safety concern at reported use levels, noting the dye is poorly absorbed and does not raise concern for genotoxicity or developmental toxicity. Some in vitro studies suggest potential cytotoxicity at high concentrations, but these are difficult to extrapolate to normal human dietary exposure. Trace unsulfonated aromatic amines may be present as impurities depending on purity grade, and the dye has been reported to cause hypertension, hypotension, skin irritation, or gastrointestinal disorders in case reports, particularly at high non-dietary doses.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
EFSA (European Food Safety Authority) (European Union)	Approved	Authorised under Regulation (EC) No 1333/2008 on food additives; maximum permitted level is 500 mg/kg food. ADI of 5 mg/kg bw/day confirmed in 2023 follow-up opinion. EU specifications require minimum 85% colouring matter. EU label must declare E132 or 'Indigotine, indigo carmine'.source
FSSAI (Food Safety and Standards Authority of India) (India)	Approved	Listed as a permitted synthetic food colour under FSS (Food Products Standards and Food Additives) Regulations, 2011. Minimum total dye content of 85% required. Final concentration in foods and beverages should not exceed 100 ppm (mg/kg) as per FSSAI general limits for synthetic colours.source
FDA (Food and Drug Administration) (United States)	Approved	Approved as FD&C Blue No. 2 (Indigotine); listed in 21 CFR Part 74 as a certified color additive subject to batch certification by FDA. Approved for general use in food, drugs, and cosmetics. No US-specific ADI set; batches must be certified before use in marketed products.source

Who should approach with care

Whose guidance would steer them away.

Children — EFSA's 2014 re-evaluation noted that at the maximum permitted level (500 mg/kg food), exposure estimates for toddlers and children at the high level could exceed the ADI of 5 mg/kg bw/day, warranting dietary caution for this age group.

Hypertension — Case reports and the published review 'Indigo Carmine: Between Necessity and Concern' (2023) document hypertension as a reported adverse effect of indigo carmine, particularly at higher doses used in medical/diagnostic settings.

Ibs — Indigo carmine has been reported to cause gastrointestinal disorders in sensitive individuals; those with existing gastrointestinal conditions such as IBS may be more susceptible to adverse GI effects.

Other — Indigo carmine should be considered a potential skin and respiratory sensitiser in occupational/inhalation exposure contexts (EFSA FEEDAP Panel, 2015); individuals with known dye hypersensitivity should consult a doctor before regular consumption of E132-containing products.

Research citations

The sources behind this verdict.

1FDA. Color Additives in Foods – Summary of Color Additives for Use in the United States. fda.gov
2PubMed. Food Safety and Health Concerns of Synthetic Food Colors: An Update, 2024. pmc.ncbi.nlm.nih.gov
3PubMed. Indigo Carmine: Between Necessity and Concern, 2023. pmc.ncbi.nlm.nih.gov
4FSSAI. Food Safety and Standards (Food Products Standards and Food Additives) Regulations – Chapter 3: Substances Added to Food, 2023. fssai.gov.in
5EFSA. Follow-up of the re-evaluation of indigo carmine (E 132) as a food additive, 2023. efsa.europa.eu
6PubMed. Follow-up of the re-evaluation of indigo carmine (E 132) as a food additive, 2023. pubmed.ncbi.nlm.nih.gov

Independently researched7 citations