Abstract
Keywords
Conclusion
In the 1998 safety assessment of HC Yellow No. 4, the Cosmetic Ingredient Review Expert Panel stated that this ingredient was safe as used in hair dyes. 1 The Expert Panel reviewed newly available studies since that assessment along with updated information regarding types and concentrations of use. 2 –6 The Expert Panel determined to not reopen this safety assessment. Therefore, the Expert Panel confirmed the original conclusion that HC Yellow No. 4 is safe for use in hair dyes.
Discussion
HC Yellow No. 4 had been used in 78 hair dyes and colors and 3 hair tints. 1 Use concentrations were reported to be up to 3.0% in oxidative and semipermanent hair colors according to a 1998 industry survey. 1 The US Food and Drug Administration reported that HC Yellow No. 4 is used in 18 hair dyes and colors, 1 hair tint, and 1 hair shampoo (coloring), 6 at a reported concentration range of 0.04% to 0.75% in hair dyes and colors 2 according to survey data. No concentration of use was reported for hair tints and hair shampoo (coloring).
The Expert Panel cautioned that HC Yellow No. 4 should not be used in formulations where N-nitroso compounds may be formed. The Expert Panel considered study results that indicate reproductive effects to rats and noted that these were all oral studies and at concentrations much higher than the reported concentration of use of 0.75%. 3 These new reproductive toxicity data, therefore, do not suggest a concern for use of HC Yellow No. 4 in hair coloring.
The Expert Panel recognized that HC Yellow No. 4 can be considered a coal tar hair dye. Accordingly, products containing this ingredient are exempt from certain adulteration and color additive provisions of the Federal Food, Drug, and Cosmetic Act, when the product label bears a caution statement and patch test instructions for determining whether the product causes skin irritation. The Expert Panel has considered concerns about such self-testing but agreed that following this procedure enables consumers to determine, prospectively, whether they will have an irritation/sensitization reaction and allow them to avoid subsequent significant exposures. In the future, the Expert Panel will consider the results of ongoing studies by the industry to evaluate the risks and benefits of consumer self-testing.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The articles in this supplement were sponsored by the Cosmetic Ingredient Review. The Cosmetic Ingredient Review is financially supported by the Personal Care Products Council.