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E132ColorantModerate concern
Indigotine
In plain words
The short version
A synthetic blue dye (indigo carmine) — common in confectionery and ice cream, with documented allergy reports.
Why we flag it amber
A synthetic blue dye (Indigotine / Blue 2). It adds colour only and can occasionally cause allergic-type reactions in sensitive people, which is why we flag it.
Safety profile
ADI of 5 mg/kg body weight. Considered safer than the Southampton six but documented to cause hypersensitivity reactions (urticaria, bronchospasm) in a small subset of individuals, particularly when injected as a diagnostic dye. Some studies report behavioral effects but evidence is weaker than for azo dyes.
The detail
A sulfonated derivative of the ancient natural indigo dye, first synthesized in the 1880s. Industrially produced by sulfonation of indigo (the molecule originally extracted from Indigofera plants and now made synthetically).
Used to color sweets, ice creams, soft drinks, baked goods, and pharmaceutical tablets and capsules. Frequently combined with tartrazine (E102) for green shades or with brilliant blue (E133) for deeper blues. Common in pill coatings.
Dark blue to purple-blue powder, moderately soluble in water. Sensitive to oxidation, heat, and light — among the less stable synthetic food dyes. Fades noticeably in light-exposed products.
Permitted in the EU, US (as FD&C Blue No. 2), and most jurisdictions. No mandatory warning label.
Sources
- WHO JECFA database: Indigotine (INS 132), ADI 0–5 mg/kg bw confirmed (2018 evaluation) — World Health Organization / JECFA, 2018. ADI of 5 mg/kg body weight
- EFSA: Follow-up of the re-evaluation of indigo carmine (E 132) as a food additive, EFSA Journal 2023;21(7):8103 — European Food Safety Authority, 2023. ADI of 5 mg/kg bw/day confirmed by EFSA
- FDA: Regulatory Status of Color Additives (FD&C Blue No. 2) — U.S. Food and Drug Administration. Permitted in the US as FD&C Blue No. 2
- EUR-Lex: Regulation (EC) No 1333/2008, consolidated text of 18 August 2026 (Annex II, Group III) — European Union (EUR-Lex), 2026. Permitted in the EU (no Annex V warning)
Checked against these sources on .
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