What is it?

“o-Phenylenediamine is an organic compound with the formula C6H4(NH2)2. This aromatic diamine is an important precursor to many heterocyclic compounds. It is isomeric with m-phenylenediamine and p-phenylenediamine, and is commonly referred to as OPD.” Wikipedia

What are the effects?

This substance belongs to the groups:

o-Phenylenediamine is on the Red List* from Campaign for Safe Cosmetics, a project of Breast Cancer Prevention Partners (previously the Breast Cancer Fund).They list the substance as probable carcinogen.

The European Chemicals Agency (ECHA) identifies that o-Phenylenediamine is “toxic if swallowed, is very toxic to aquatic life with long lasting effects, is harmful in contact with skin, causes serious eye irritation, is harmful if inhaled, is suspected of causing genetic defects, is suspected of causing cancer and may cause an allergic skin reaction.”

O-Phenylenediamine and its salts are prohibited for use in cosmetic products in the European Union. The compound is listed in annex II (list of substances prohibited in cosmetic products) by CosIng, the European Commission database for information on cosmetic substances and ingredients.

This substances contains amines and may form toxic nitrosamines in products.


Even though it is not listed on the list of ingredients, products with o-Phenylenediamine may contain impurities from:

  • Nitrosamines –  Linked to endocrine disruption, cancer, organ system toxicity, and is prohibited to use in cosmetics in the EU and Canada.

* “The Red List includes chemicals found in personal care products that pose serious, chronic health concerns including cancer, hormone disruption, and reproductive and developmental harm. The list also flags chemicals that are banned or have use restrictions by the U.S. or other world governments, ingredients that adversely impact worker health, and ingredients that are widely used in products marketed to women of color.” – Campaign for Safe Cosmetics

How is it used?

o-Phenylenediamine mainly functions as a dye substance in oxidative hair dye products. The substance can be found in cosmetic products* such as hair dyes, hair colors, hair tints and rinses.

We use the European Commissions definition of Cosmetics:
“Cosmetics range from everyday hygiene products such as soap, shampoo, deodorant, and toothpaste to luxury beauty items including perfumes and makeup”.

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