Here's why:
* Scalp sensitivity: Shampooing can leave your scalp slightly irritated, making it more sensitive to the chemicals in hair dye. Waiting allows your scalp to calm down and minimizes the risk of irritation or allergic reactions.
* Oil barrier: Your scalp naturally produces oils that help protect your hair. Shampooing removes these oils, making your hair more porous and susceptible to dye absorption. Waiting allows your scalp to replenish its natural oils, creating a better barrier and ensuring more even color results.
* Hydration: Shampooing can dry out your hair, making it more prone to damage from the dyeing process. Waiting allows your hair to rehydrate, resulting in healthier and less damaged hair.
Exceptions:
* Some hair dyes specifically recommend applying them to freshly washed hair. Always follow the instructions on the product label.
* If you have oily hair, waiting longer than 24 hours may be necessary.
Remember: If you experience any discomfort or allergic reactions, stop using the dye immediately and consult a dermatologist.