Question: how long should you wait to dye your hair after using henna?
Answer: Hair Dyes after Henna: If henna isn't for you and you want to get back to commercial hair dyes, it's fine to backtrack within the first two to three weeks. Ideally, however, we recommend that you wait two months or longer after your last henna application. If that is too long for you then aim for at least one month.