Yes, generally it is recommended to dye hair when it is not freshly washed.
According to expert advice, the general rule of thumb is to not wash your hair the day of coloring – or even the day before coloring if your hair washing routine allows. You might hear colorists say a second (or even third) day hair is best.
Why Dyeing on Unwashed Hair is Recommended
Dyeing hair requires the color chemicals to interact with the hair shaft. Having a natural buildup of oils can offer several benefits during this process.
- Natural Protection: Unwashed hair produces a natural oil protective layer. This layer can help shield your scalp from irritation caused by the dyeing chemicals.
- Easier Application: The natural oils can sometimes help the dye distribute more evenly through the hair.
- Reduced Sensitivity: With a protective barrier on the scalp, you might experience less itching or burning during the coloring process.
Therefore, having slightly "dirty" hair (meaning it hasn't been washed recently) is often preferred over freshly washed hair when applying dye. This applies to most types of hair dye, including permanent, semi-permanent, and highlights.
However, note that this guidance is for hair that is simply unwashed for a day or two, not hair that has excessive product buildup or is excessively greasy, as that could potentially interfere with color penetration.
