Blue 1 — Allergy Risk & Safety Profile
INCI: CI 42090
Key Facts
- CAS Number
- 3844-45-9
- Category
- colorant
- Risk Level
- low
- Common Allergen
- No
- Found In
- mouthwash, shampoo
Is Blue 1 safe in cosmetics?
Blue 1 is rated low risk in cosmetic products. It is not classified as a common allergen and is generally well-tolerated by most skin types. Safer alternatives include Iron Oxides, Mica, Titanium Dioxide. Commonly found in mouthwash, shampoo.
What is Blue 1?
Blue 1 is a colorant commonly used in cosmetic and personal care products. It is generally considered safe for use in cosmetics at recommended concentrations.
Allergy & Safety Information
Blue 1 is considered safe for cosmetic use. No significant safety concerns have been identified at typical use concentrations. As with any cosmetic ingredient, discontinue use if irritation occurs.
This ingredient is considered low risk from an allergenicity perspective. Reactions are uncommon at typical cosmetic use concentrations. However, no ingredient is universally safe — if you notice redness, itching, or irritation after using a product containing this ingredient, discontinue use and monitor whether symptoms resolve.
About Colorant / Pigment Ingredients
Colorants are used in makeup and some skincare products to provide colour. Inorganic colorants (iron oxides, ultramarines, chromium oxides) and organic dyes (CI numbers) are regulated by cosmetic authorities for purity and safety. Iron oxides naturally contain trace metal impurities including nickel, which can cause reactions in nickel-sensitised individuals.
Relevance for Blue 1: Coal tar dyes (FD&C and D&C numbers) are more likely to cause reactions than inorganic mineral pigments. Azo dyes can release aromatic amines upon degradation. Metallic and shimmer pigments (mica, bismuth oxychloride) may contain trace nickel contamination.
How to Identify Blue 1 in Products
Cosmetic ingredients are listed by their INCI (International Nomenclature of Cosmetic Ingredients) name in descending order of concentration. To check whether a product contains Blue 1, scan the ingredient list for its INCI name exactly as it appears above. Ingredients present at 1% or less may appear in any order after the 1% threshold.
Product types to prioritise checking: Mouthwash, Shampoo. These product categories are the most common sources of Blue 1 exposure based on formulation data.
Not sure if your products contain Blue 1? Paste the ingredient list into the free ingredient checker to scan for Blue 1 and other allergens automatically.
Safer Alternatives
These ingredients serve a similar function with lower allergy risk:
Frequently Asked Questions
Is Blue 1 safe for sensitive skin?
Blue 1 is generally well-tolerated, even by sensitive skin types.
What products contain Blue 1?
Blue 1 is commonly found in mouthwash, shampoo.
What does Blue 1 do in cosmetics?
Blue 1 functions as a colorant in formulations.
Related Guides
Is Blue 1 causing YOUR skin reactions?
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