Science
Mechanism of Action
This ingredient functions as a cosmetic colorant by physically reflecting specific wavelengths of light, delivering a precise red hue to topical formulations. It does not exhibit any active biological mechanism on the skin itself.
Research
Clinical Evidence
Low confidence3%
Transparency
Dusting Analysis
Pigment Red 4 is typically incorporated into formulations at a maximum concentration of 3%, a quantity not associated with the micro-dosing concerns of highly potent ingredients requiring stringent dusting controls.
The Formula
Formulation
Stability
Pigment Red 4 exhibits robust resistance to acids, alkalis, alcohol, and water, maintaining optimal stability within a pH range of 5.5 to 8.0. It possesses a medium lightfastness rating of Grade 6, indicating potential darkening upon prolonged solar exposure. While some sources note poor general heat resistance, it tolerates temperatures up to 140°C-180°C for short durations.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) has deferred evaluation, citing assessment by the U.S. FDA, which approves Pigment Red 4 (D&C Red No. 36) for use in externally applied cosmetics, including lip products, at a maximum concentration of 3%. Importantly, it is strictly prohibited for use in the eye area. The European Union's SCCS approves its use without specific restrictions. However, Canada and China also impose a 3.0% maximum concentration, with China additionally forbidding its use in hair dye products. As a member of the azo dye family, it is associated with broader concerns regarding potential mutagenicity, genotoxicity, and carcinogenicity. Certain individuals, particularly those with sensitive skin, may experience mild irritation or allergic reactions. The Environmental Working Group (EWG) assigns a high rating for use restrictions.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Pigment Red 4 serves as an FDA-approved colorant providing vibrant red hues for external cosmetic applications up to 3%; however, its association with the azo dye family, potential for sensitive skin irritation, and high regulatory restrictions warrant a cautious formulation approach.
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