What is Henna?
Henna is a plant, Lawsonia inermis, that grows in the middle east. It's leaves are harvested, dried and ground into a very fine powder. Body art quality henna has been triple sifted so that it is ultra fine and free from all impurities. The powder is then made into a paste using various ingredients such as essential oils, coffee, tea, lemon juice, and sugar.
How Long Does Henna Last?
The short answer : 7-14 days.
The long answer: Henna dyes the top layer of your skin and the stain lasts as long as that skin lasts. Skin cells typically last around 2-3 weeks but everyone is a little different. Some people have henna designs that last nearly a month while others might only last a week. A lot of it also comes down to care. Frequent washing and scrubbing will take the design off faster. Protecting your henna from water, harsh chemicals and exposure to friction will keep your design lasting a lot longer.
What is Black Henna?
There is no such thing as black henna. Henna is a plant and the colors of the natural henna range from orange, burnt red to dark brown. There are techniques that involve caustic chemicals that can turn the henna black but this can cause severe irritation and is NOT RECOMMENDED.
Anyone claiming to use black henna is most likely using black hair dye. Black hair dye is not safe for long term exposure to the skin and can cause painful chemical burns and may even lead to scarring. Always ask your henna artist what ingredients are in their henna and be weary of any artist that didn't mix the henna themselves or cannot tell you exactly what is in the henna. Be especially cautious when traveling abroad.
What is White Henna?
White henna is not really henna. It is medical adhesive used my doctors and makeup artists to glue prosthetics to the skin. It is not especially dangerous but it is not a natural compound and the same rules for henna care do not apply.