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HC YELLOW NO. 9

Description

HC Yellow No. 9, also known as 1-Methoxy-3-(β-hydroxyethylamino)-4-nitrobenzene, is a synthetic hair dye ingredient primarily used in semi-permanent hair coloring products. This water-soluble compound imparts a vibrant yellow hue to hair and is often combined with other dyes to create a range of warm tones. HC Yellow No. 9 is particularly effective on lighter hair shades and can produce golden to brassy results depending on the concentration and application method.

The ingredient penetrates the hair shaft, depositing color molecules that adhere to the cortex without significantly altering the hair's natural structure. This non-oxidative dye gradually fades with washing, typically lasting 4-6 weeks. HC Yellow No. 9 is considered a low molecular weight dye, allowing for easier penetration and more uniform color distribution.

While generally regarded as safe for use in hair coloring products, some individuals may experience skin sensitization or allergic reactions. Patch testing is recommended before use. The ingredient is regulated by cosmetic authorities worldwide, with concentration limits varying by region to ensure consumer safety.