Science
Mechanism of Action
This ingredient operates as a pH indicator by altering its electronic structure in response to proton donation or acceptance. This molecular change leads to a highly conjugated, quinonoid-like form in alkaline conditions, causing a distinct color shift from yellow (below pH 3.0) to blue (above pH 4.6). Its primary utility in cosmetic formulations is centered on its colorant properties, rather than active skin benefits.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Tetrabromophenol Blue exhibits stability under standard laboratory conditions. Its characteristic pH indicator color transition occurs between pH 3.0 (yellow) and pH 4.6 (blue). For optimal stability, aqueous solutions are not recommended for storage for longer than one day.
Conflicts
- Undiluted Tetrabromophenol Blue is corrosive to eyes; appropriate dilution is crucial for ocular safety.
Safety
Safety Profile
Evaluated as safe for use in cosmetics by the CIR Expert Panel and the EU's SCCS, with a maximum on-head concentration of 0.2% in hair coloring products. It is listed by the FDA as an approved cosmetic color additive. Studies indicate a low risk of skin sensitization (up to 2%) and no dermal irritation, though skin staining can occur. While the undiluted form is corrosive to rabbit eyes, it is not considered an ocular irritant when diluted to 2%. It is deemed non-genotoxic.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Tetrabromophenol Blue is a well-studied and safe colorant, primarily functioning as a pH indicator in hair products, with no direct efficacy for skin benefits in precision skincare formulations.
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