Henna or Mehndi is a dry powder of the henna plant (Lawsonia inermis) which contains hydroxy-1,4-naphthoquinone (HQN) an active ingredient. This red-orange dye is present in the leaves of the henna plant responsible for producing a brown, orange-brown, or reddish-brown tint.

On February 25, 2022, FDA published safety and regulatory information on “decal,” henna, and “black henna” temporary tattoos. This article summarises information about temporary tattoos and their chemical compositions.

What is Henna, or Mehndi, and “Black Henna”?

Henna or Mehndi is a dry powder of the henna plant (Lawsonia inermis) which contains hydroxy-1,4-naphthoquinone (HQN) an active ingredient. This red-orange dye is present in the leaves of the henna plant responsible for producing a brown, orange-brown, or reddish-brown tint.

Traditionally, in the Indian subcontinent, Mehndi is considered a ceremonial art. The traditional recipe of Mehndi was a mere paste of the dry leaves of the henna plant.

Today, each and every Heena and Mehandi products include additives for color enhancement and fragrance, one of the ingredients commonly used is PPD. Black Henna is the best example of a PPD mixed Henna.

What is phenylenediamine?

Phenylenediamine (PPD) is an ingredient commonly used in hair dyes. The Centers for Disease Control and Prevention lists PPD as being a contact allergen (the substance might irritate the skin or trigger an allergic reaction). PPD exposure routes are through inhalation, skin absorption, ingestion, and skin and/or eye contact. Symptoms of exposure to PPD include throat irritation (pharynx and larynx), bronchial asthma, and sensitization dermatitis.

According to FDA’s report, PPD may have caused dangerous skin reactions in some people using Henna. That’s the reason hair dyes have a caution statement and instructions to do a “patch test” on a small area of the skin before using them.

Next time, if you are using Henna products, make sure it is PPD free.