What is typically the primary change caused by temporary hair color?

The primary change caused by temporary hair color is a physical change to hair appearance. Temporary hair colors are formulated to deposit color on the hair's outer layer without penetrating the hair shaft. This means they alter how the hair looks—for instance, providing a new shade or vibrancy—without changing the hair's natural structure or composition. Temporary colors typically wash out after a few shampoos, which reinforces the fact that they are meant for short-term use and do not create lasting alterations.

Permanent alteration of hair structure relates to processes that change the internal makeup of the hair, such as bleaching or permanent dyes, which is not the case with temporary colors. Deep conditioning treatments are aimed at improving the health and moisture of hair rather than changing its color. The restriction of natural oils doesn't apply here, as temporary hair colors do not affect the scalp or hair's natural oil production in a significant way.