"After having your hair colored, wait a full 72 hours before shampooing," says Eva Scrivo, a hairstylist in New York City. "It takes up to three days for the cuticle layer to fully close, which traps the color molecule, allowing for longer lasting hair color."
Don't Wash Your Hair—at First
We all ask ourselves the same question a day or two after our color appointment: “How long do I have to wait before washing my hair?” Celebrity colorist Aura Friedman makes it simple: “Wait at least three days before shampooing your hair after color,” she says.
So, you've just dyed your hair and are wondering if dry shampoo will work? Rest assured that yes! It can be used on freshly coloured locks. Some people find that washing their hair too much can damage the integrity of the hair colour.
Do not shampoo
Once applied, simply rinse out the hair dye and condition as usual. (IMPORTANT: This ONLY applies to semi-permanent hair colors.) This will allow your hair to absorb the hair dye.
Wash Hair With Cold Water
To keep your new hair color vivid and bright, we advise that you wash your hair with cold water (as cold as is bearable). Cold water keeps the hair cuticles closed and therefore stops the color running out and fading too soon.
You generally shouldn't shampoo immediately before coloring, because this will remove the natural oils that help protect your scalp during the coloring process. It's best to shampoo 12 - 24 hours before coloring when using semi-permanent or demi-permanent hair color. Shampoo 24 hours before using permanent color.
Since semi-permanent hair dye isn't formulated with peroxide or ammonia, it can be beneficial to use it on wet hair. This will open up the cuticles of the hair shaft and allow the color to absorb better into wet strands.
Not using a conditioner for color-treated hair
Dyed Hair is more likely to become dry and brittle, so treat it often with conditioners specifically formulated for color-treated hair.
Shampoo 24 to 48 Hours Before Coloring Your Hair
When it's time to wash out your dry shampoo, do so a day or two before having your hair dyed. This gives your scalp a chance to create a healthy layer of sebum oil to coat your skin and protect it from the harsher chemicals in your dye.