Henna brows are a form of eyebrow tinting that is used to stain the skin beneath the brow hairs. The purpose of this is to cast a shadow or create an illusion of depth and fullness in the area, visually filling in any sparseness. Henna is a natural dye made from a plant known as hina or the henna tree. Brow henna lasts 7-14 days on the skin and 4-6 weeks on the hair.