Blue 1 (Brilliant Blue FCF, E133): how it is made, where it shows up, absorption and ADI evidence, FDA vs EU vs California school rules, and how to spot it.
9/8/2026 · 9 min read · Chris Carrillo · Reviewed by Armin Rad, Co-Founder & CTO, Aurascan · Last reviewed 9/8/2026
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Written by Chris Carrillo. Reviewed by Armin Rad, Co-Founder & CTO, Aurascan. It cites 4 sources; use the source list and methodology to check the evidence directly.
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View the sample resultBrilliant Blue FCF (FD&C Blue No. 1, E133) is a synthetic triarylmethane dye derived from petroleum hydrocarbons, providing vibrant cyan-blue shades in foods, beverages, and cosmetics. Regulators such as the FDA and EFSA permit its use because most of it passes through the gut unabsorbed, though state policies like California AB 2316 restrict it in school foods.
Key takeaways:
Brilliant Blue FCF is a synthetic organic compound classified chemically as a triarylmethane dye. On commercial specification sheets, it is frequently designated by its chemical formula C37H34N2Na2O9S3 and its Color Index number, CI 42090. As recorded in the PubChem Compound database, it presents as a dark reddish-blue or violet powder that dissolves readily in water to yield an intensely bright, clear blue solution with a high molecular weight of approximately 792.85 grams per mole.
Manufacturing Brilliant Blue FCF involves an organic synthesis process starting from aromatic hydrocarbons derived from petroleum feedstocks. Specifically, 2-formylbenzenesulfonic acid is condensed with an appropriate alkylated aniline derivative, followed by oxidation and neutralization to produce a disodium sulfonate salt. Because industrial synthesis can yield minor chemical intermediates and trace impurities, regulatory agencies require batch certification to verify that heavy metals like lead stay strictly below 10 parts per million (ppm), arsenic stays below 3 ppm, and total unreacted starting chemicals remain strictly within defined purity thresholds of at least 85 percent pure dye before entering commerce. Analytical methods such as those reviewed in research on A Reliable and Simple Voltammetric Method for Analysis of Brilliant Blue FCF allow labs to verify exact concentrations in commercial lots.
Unlike natural plant extracts, synthetic dyes like Blue 1 offer food processors exceptional chemical stability. Brilliant Blue FCF resists degradation caused by heat processing up to standard baking temperatures, light exposure, low pH acidity down to pH 3, and microbial activity. These physical properties allow consumer packaged goods to retain their bright, uniform visual appeal over long shelf lives of 12 to 24 months without rapid fading or hue shifting.
Brilliant Blue FCF serves primarily as a visual colorant across a broad spectrum of consumer goods. Because human perception of flavor is heavily tied to visual appearance, food manufacturers utilize Blue 1 at typical food concentrations of 5 to 100 parts per million (0.0005% to 0.01% by weight) to reinforce expectations of berry, blueberry, blue raspberry, mint, and tropical punch flavors in packaged items.
You will commonly find Brilliant Blue FCF in products such as:
In addition to delivering standalone blue shades, Brilliant Blue FCF is often combined with other certified color additives. When blended with azo dyes, such as when formulating with What Is Tartrazine (Yellow 5)? Uses, Safety, and Labeling, processors achieve a wide palette of vibrant green tones for lime or sour apple products. Blending Blue 1 with red colorants, including synthetic dyes discussed in What Is Erythrosine? Uses, Labels, and Safety, creates deep purple and grape hues. Outside of consumable products, analytical chemists and industrial researchers study the compound for wastewater treatment testing, such as evaluating Development of New Biosorbent Based on Crosslinked Chitosan Beads with High Brilliant Blue FCF Removal Efficiency to capture synthetic dyes from manufacturing runoff.
Comprehensive toxicological evaluations conducted by international scientific panels conclude that Brilliant Blue FCF exhibits low systemic toxicity when consumed at typical dietary levels. A primary factor supporting its safety profile is its pharmacokinetic behavior: upon oral ingestion, the vast majority of Brilliant Blue FCF passes through the gastrointestinal tract unabsorbed and is excreted directly in the feces. Research indicates that systemic absorption across intact intestinal barriers is generally below 5 percent, meaning over 95 percent leaves the human body completely intact.
The European Food Safety Authority (EFSA) established an Acceptable Daily Intake (ADI) of 6 milligrams per kilogram of body weight per day for Brilliant Blue FCF (E133). For a 60-kilogram adult, that EFSA figure equates to 360 milligrams per day, far above typical dietary intake. In the United States, the FDA does not publish a separate ADI; it permits FD&C Blue No. 1 under 21 CFR 74.101 subject to batch certification.
However, a scientific limitation must be recognized. Available toxicological studies cannot completely eliminate the possibility of idiosyncratic reactions in highly sensitive individuals, nor can they definitively quantify the long-term biological effects of consuming complex mixtures of multiple synthetic dyes over decades. Furthermore, in vitro research on blood components reported in New Findings Regarding the Effects of Selected Blue Food Colorants (Genipin, Patent Blue V, and Brilliant Blue FCF) on the Hemostatic Properties of Blood Components In Vitro has examined whether high concentrations of colorants interact with hemostatic mechanisms, though these laboratory findings do not demonstrate harm under normal dietary exposure conditions.
As of September 8, 2026, Brilliant Blue FCF continues to hold full approval for use in foods, beverages, dietary supplements, and cosmetics under federal United States regulations and European Union legislation. In the European Union, it is designated as food additive E133. Under Title 21 of the U.S. Code of Federal Regulations, it is listed as FD&C Blue No. 1, requiring mandatory batch-by-batch certification by the FDA.
While federal agencies maintain their existing safety standards, regulatory momentum has shifted significantly toward state-level oversight and broader legislative initiatives in the United States. In California, the enactment of Assembly Bill 2316 established restrictions prohibiting public schools from serving foods containing specific synthetic food dyes, including Blue No. 1, effective December 31, 2027. This measure forms a cornerstone of what policy advocates refer to as the broader US petroleum-dye phase-out plan for school lunchrooms, prompted by concerns raised by the California Office of Environmental Health Hazard Assessment (OEHHA) regarding dye-induced behavioral sensitivities in school-aged children.
Unlike synthetic azo dyes such as Tartrazine or Allura Red, which require a mandatory warning label in the European Union regarding activity and attention in children following the 2007 Southampton study, Brilliant Blue FCF is a triarylmethane dye and is not subject to that specific EU warning label mandate. Nevertheless, European processors frequently replace synthetic colors to accommodate consumer demand for clean-label formulations. Similar regulatory scrutiny has surrounded other additive categories, as seen in evaluations of What Is Titanium Dioxide? Uses, Safety, and Labeling.
For the broad population, consuming foods containing Brilliant Blue FCF does not trigger noticeable adverse reactions. The most common physical observation following heavy consumption of dark blue icings or concentrated sports beverages is a harmless, temporary greenish or bluish discoloration of the stool, caused by the unabsorbed dye passing through the digestive tract.
Despite its general safety record, scientific reviews and clinical observations highlight two sensitive populations that warrant attention:
A specialized clinical concern occurred historically when Blue 1 was used as a diagnostic coloring agent in enteral tube feedings to detect pulmonary aspiration. Consequently, the FDA issued a public health advisory in 2003 cautioning against the addition of FD&C Blue No. 1 to enteral feeding solutions.
Identifying synthetic blue dyes requires scanning the ingredient panel on packaged foods, personal care products, and over-the-counter medications. Food labeling laws require manufacturers to declare added colors by their recognized regulatory names, although the terminology varies by jurisdiction and product category.
To identify this additive, check the ingredient list for the following synonyms:
Aluminum lakes, listed as "Blue 1 Lake", are insoluble pigment forms created by precipitating Brilliant Blue FCF onto an alumina substrate. These lake pigments typically contain between 10 percent and 40 percent pure colorant and are specifically formulated for oil-based confections, dry cake mixes, and tablet coatings to prevent bleeding or color migration. When reading labels on personal care items like mouthwash or shaving gel, the dye is almost universally declared as CI 42090 or FD&C Blue No. 1.
Driven by consumer preferences for plant-derived ingredients and evolving school nutrition policies, food manufacturers are increasingly reformulating products using natural blue color alternatives. Natural blue pigments are among the most difficult colors to isolate from botanical sources due to pH instability and thermal sensitivity, but recent extraction innovations have expanded available options.
Leading natural color substitutes include:
While natural colorants provide clean-label alternatives, they typically require larger dosage volumes - often 3 to 10 times higher concentration by weight - to match the visual intensity of synthetic dyes and may introduce subtle botanical flavors or increased production costs into the final product.
Yes. Brilliant Blue FCF and FD&C Blue No. 1 are identical chemical compounds (CI 42090). "FD&C Blue No. 1" is the official regulatory term in the United States, while "Brilliant Blue FCF" is used internationally and "E133" is used across the European Union.
Brilliant Blue FCF is poorly absorbed by the human gastrointestinal tract, with over 95 percent passing through the gut unchanged. When consumed in significant amounts, the concentrated blue dye mixes with natural yellow-brown bile pigments, often creating a harmless green or blue tint in bowel movements.
Brilliant Blue FCF is approved by major federal authorities worldwide, including the FDA and EFSA. However, regional restrictions exist; for example, California passed AB 2316 to ban Blue 1 and other synthetic dyes from public school food programs starting December 31, 2027.
Scientific evaluations, including findings from California OEHHA, suggest that synthetic food dyes can contribute to behavioral changes or exacerbate hyperactivity in certain sensitive children. However, general population toxicity is low, and major federal agencies do not classify it as a broad neurotoxin.
FD&C Blue No. 1 is a water-soluble dye suitable for clear drinks, syrups, and gels. Blue 1 Lake is an oil-dispersible pigment made by binding the dye to an aluminum substrate, preventing color from bleeding or dissolving in fats, dry powders, and tablet coatings.
Yes. Brilliant Blue FCF is synthetically produced from petroleum-derived hydrocarbons and contains no animal by-products or gluten. Some consumers choose to avoid it for environmental or synthetic ingredient preferences, but it fits vegan and gluten-free diets.
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