Which hair colors do NOT require a patch or predisposition test?

Temporary hair colors do not require a patch or predisposition test because they are typically less chemically intense and do not penetrate the hair shaft as deeply as other types of color formulations. Temporary colors usually coat the hair rather than alter its structure, making them less likely to cause an allergic reaction. They are designed to wash out within a few shampoos, reducing the risk of long-term adverse effects associated with more permanent solutions.

In contrast, permanent and demi-permanent hair colors contain stronger chemicals that can penetrate the hair and interact with the scalp, necessitating a patch test to ensure the client does not have a sensitivity or allergy to the ingredients. Highlights might involve the use of bleach or other chemical agents, which also can prompt the need for a patch test for safety reasons. Therefore, temporary colors stand out as the safest option regarding the requirement for patch tests.