Rainbow Henna Rainbow Henna has no additives, chemicals, or pesticides. Rainbow Henna coats each hair shaft with color. Blends naturally. Fades gradually. Lasts 4-6 weeks. Smooths and seals the hair's cuticle for greater shine and body. Our custom-tailored recipes can be used for special effects, covering grey, and improving texture.Note: Henna has no lightening action.History of Henna Secrets of beauty have been cherished throughout the ages. One of the oldest beautifers known is Henna. Famous beauties such as Nefertiti and Cleopatra used Henna to enhance their hair coloring. Silent film stars Theda Bara and Clara Bow colored their hair with Henna to add to their mystery. Today, Henna is used by women and men who understand how to be naturally beautiful.