Mississippi Cosmetology Board Practice Exam 2025 - Free Cosmetology Practice Questions and Study Guide

When hair that has been treated with henna is subsequently colored, it can lead to unpredictable results due to the nature of henna as a dye. Henna coats the hair shaft and can create a unique base that may react unpredictably with chemical color products. The reaction may not be uniform throughout the hair, resulting in variances in color depth and tone. This unpredictability is compounded by the fact that henna can impart a range of colors—typically reddish or brownish hues—substantially differing from the desired color outcome when mixed with conventional hair dyes.

Other outcomes, such as the hair becoming resistant to dye or not taking color at all, may occur but are less common. Residual henna may alter the chemical composition of the hair, impacting how new dyes bond. Therefore, while some hair might not take color at all, the hallmark of using henna as a base is more often the unpredictability in the resulting color than complete resistance to new hair coloring. The complexity of this interaction necessitates caution for anyone considering coloring hair that has previously been treated with henna.