Table 1:

Summary of colorants using in hair fiber products (2–4, 7, 9, 10)

Colorant	Colour Index (CI)	Nano particle	Molecular Formula	NP Composition Ratio%	Toxicological Effect
Black	CI 77266	Carbon Black	C	-	Carcinogenic
Red	CI 77491	Iron Oxide Red	Fe2O3	Less than 50	Genotoxic
Yellow	CI 77492	Iron Oxide Yellow	FeO(OH) · xH2O	More than 50	Respiratory Problems
Black	CI 77499	Iron Oxide Black	FeO · Fe2O3	Less than 10	Genotoxic
White	CI 77891	Titanium Dioxide	TiO2	17–35	Cytotoxic
White	CI 77947	Zinc Oxide	ZnO	-	Genotoxic