Baby Safety / Compounds / Indigotine (Indigo Carmine; FD&C Blue No. 2; E132)

Is Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) safe for babies and kids?

Moderate risk for kids

Infants are more vulnerable to Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

What is indigotine (indigo carmine; fd&c blue no. 2; e132)?

The IUPAC name is disodium;2-(3-hydroxy-5-sulfonato-1H-indol-2-yl)-3-oxoindole-5-sulfonate.

Also known as: disodium;2-(3-hydroxy-5-sulfonato-1H-indol-2-yl)-3-oxoindole-5-sulfonate, Indigo carmine, Acid Blue 74, Indigotindisulfonate sodium.

IUPAC name
disodium;2-(3-hydroxy-5-sulfonato-1H-indol-2-yl)-3-oxoindole-5-sulfonate
CAS number
860-22-0
Molecular formula
C16H8N2Na2O8S2
Molecular weight
466.4 g/mol
SMILES
C1=CC2=C(C=C1S(=O)(=O)[O-])C(=C(N2)C3=NC4=C(C3=O)C=C(C=C4)S(=O)(=O)[O-])O.[Na+].[Na+]
PubChem CID
2723854

Risk for babies

Moderate risk

Infants are more vulnerable to Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

Neonates and infants up to 12 months have incomplete blood-brain barrier development, immature Phase I/II metabolic enzymes (particularly CYP3A4, UGT1A1), and higher gastrointestinal permeability. Equivalent doses produce higher internal concentrations and longer residence times.

What to do: Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

Risk for pregnant and nursing people

Context-dependent

Pregnancy alters the metabolism and distribution of Indigotine (Indigo Carmine; FD&C Blue No. 2; E132), potentially increasing fetal exposure. The developing embryo/fetus is vulnerable during organogenesis (weeks 3-8) and neurological development. Placental transfer should be assumed.

No specific reproductive toxicity data identified, but pregnancy-specific safety data is limited for most chemicals. Precautionary minimization of exposure is recommended.

What to do: Minimize exposure during pregnancy and lactation. Consult healthcare provider regarding specific risks. Consider alternative products with lower hazard profiles.

Regulatory consensus

3 regulatory and scientific bodies have classified Indigotine (Indigo Carmine; FD&C Blue No. 2; E132). The classifications differ — that's the data.

AgencyYearClassificationNotes
IARC2014Not evaluated by IARC for carcinogenicity — Indigotine (Indigo Carmine; FD&C Blue No. 2; E132; CAS 860-22-0; disodium 3,3'-dioxo-2,2'-bi-1H-indole-5,5'-disulfonate; the sodium salt of indigo-5,5'-disulfonic acid) is a sulfonated indigo dye — structurally distinct from synthetic azo dyes — permitted as a food color additive in both the United States (FDA FD&C Blue No. 2, ADI 5 mg/kg/day) and the European Union (E132, EFSA ADI 5 mg/kg/day); Indigotine was NOT included in the Southampton 2007 hyperactivity study (McCann et al., Lancet) and is not subject to the EU mandatory hyperactivity warning label; it is one of the less controversial certified food colorants in current use; no IARC, US EPA, or EFSA carcinogenicity classification exists
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 17 positive / 10 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 17 positive / 10 negative reports)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where kids encounter indigotine (indigo carmine; fd&c blue no. 2; e132)

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Consumer Products — food products, candy, beverages, cosmetics, supplements

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Indigotine (Indigo Carmine; FD&C Blue No. 2; E132):

  • Natural dyes (indigo, madder, weld) where applicable
    Trade-offs: Lower colorfastness. Limited palette. Higher cost per unit.
    Relative cost: 2-5× conventional
  • Reactive dyes with lower aquatic toxicity
    Trade-offs: Not suitable for all fiber types
    Relative cost: 1.2-2×

Frequently asked questions

Is indigotine (indigo carmine; fd&c blue no. 2; e132) safe for kids?

Infants are more vulnerable to Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

What products contain indigotine (indigo carmine; fd&c blue no. 2; e132)?

Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); food products (Consumer products).

What should I do if my child is exposed to indigotine (indigo carmine; fd&c blue no. 2; e132)?

Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

Why do regulators disagree about indigotine (indigo carmine; fd&c blue no. 2; e132)?

Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) has been classified by 3 agencies including IARC, EPA CTX / Genetox, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Indigotine (Indigo Carmine; FD&C Blue No. 2; E132) in the baby app

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Sources (1)
  1. Indigotine Indigo Carmine FD&C Blue No 2 E132 CAS 860-22-0 CI Food Blue 1 Acid Blue 74 Disodium Indigo-5,5'-Disulfonate; EFSA 2014 ADI 5 mg/kg/day No Genotoxicity Ames Negative EFSA Journal 2014;12(7):3768; FDA ADI 5 mg/kg/day FD&C Blue No 2; NOT Southampton 2007 Hyperactivity Study No EU Warning Label; Permitted US EU Canada Australia NZ Japan; Medical Use IV 200mg Urological Surgery Ureteral Identification Hypotension Bradycardia; GI Absorption <1% Disulfonate Groups; No Azo Bond No Azo Reductase Metabolism; Indigo Chromophore Bicyclic Oxindole UV-Vis 610nm Blue; Sulfonated Indigo Parent Indigofera Tinctoria Natural; Synthetic Production Sulfonation Indigo CAS 482-89-3 (2014) — regulatory

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →