You may have read on various websites about the health dangers of "black henna"... I will once again reiterate the importance of knowing what you're getting and what the risks are.
Please note: not all 'black henna' artists are bad people; the majority don't even realize how unsafe it is! Knowledge is power, and my message will provide you some insight on the risks.
There is no such thing as black-coloured henna. The jet black colour is achieved from a chemical ingredient added to the paste. This synthetic ingredient is usually a coal-tar dye called "PPD" or para-Phenylendiamine. It is absorbed into your skin, enters your blood stream, and in turn passes through your kidneys and liver. People have had extreme reactions and lifelong damage.
The chemical burn caused by PPD causes the skin to blister, swell and itch. You can have a permanently scar. You can also develop allergies to other things, even if you use it once.
Every single application of "black henna" affects you - the toxins stay in your body for the rest of your life.
Even if you don't see a visible reaction to PPD, it is still harmful. PPD penetrates deep into the skin, reaching the dermis (living cells) and passing into the blood stream. This is in contrast to henna, which only penetrates as far as the dead skin cells of the epidermis. Once in the blood stream, PPD may have effects on the kidneys, resulting in kidney impairment. Repeated or prolonged inhalation exposure may cause asthma, so those who prepare PPD-based black henna are at risk as well. PPD never leaves your body - in fact, it accumulates in your body after each and every exposure to it, leading to permanent injury and sensitivities/allergies.
Imagine not being able to use sunscreen, cosmetics, dark-coloured fabrics, leather, and hair dyes ever again. And that's the best-case scenario.
PPD is regulated by Health Canada for limited use in products, such as hair dyes. It is not intended for use directly on skin, especially in high concentrations.
Since Health Canada ruled that using PPD in henna, vendors have started using other chemicals: Nigrosene (or Nigrosine, also called "Acid Black 2") is an Azo dye. It has been commonly used in shoe polish, and dying leather and plastic. Nigrosene is also very harmful and can cause similar reactions (blistering, itching, swelling, scars) and allergies, and has been linked to cancer.
If a vendor tells you the colour is from a food dye, they aren't telling you the truth: Food dye will not make henna black. Food dye cannot stain skin for days. The dye molecule is too big to penetrate into the skin, so it sits on the surface. It can be washed away with soap and water.
What to do if you have a reaction to "black henna" :
The doctor will most likely prescribe a topical steroid cream to reduce swelling, itching and blistering.
Where is "black henna" usually found?
Why even bother with "black henna"?
People have told me they like how it looks like a real tattoo. A safe alternative are Temptu theatrical body paints. These are FDA-approved body paints that have been used on television and in movies to create convincing tattoos. Many colours to choose from, easy to apply and lasts for days.
How can you tell if an artist is using real henna??
Essential oil is an optional ingredient - Tea Tree, Lavender, Cajeput, Ravensara and Eucalyptus are considered "safe" essential oils. (Mehndi or Mahalabya oil are unregulated and may contain strong Clove Bud essential oil, ammonia and even kerosene!)
How to report "black henna" use in Canada
Please contact your nearest Health Canada Product Safety Office if you suspect that PPD is being used by a local vendor, or if you suspect you have suffered an adverse reaction from a "black henna" temporary tattoo. Call toll-free 1-866-662-0666 or send an email to firstname.lastname@example.org.
If sensitivities / allergies form as a result of 'PPD' exposure, here are substances you may also react to: