PPD (paraphenylenediamine) is the most widely used permanent hair dye as it is one of the few dyes that can successfully colour light or grey hair back to a dark colour. Permanent or oxidative hair colorant products involve the mixing of the 'hair dye' substance (e.g. PPD) with another substance called a 'coupler' immediately before applying to the hair.
The two then react to form the required colour inside the hair itself and, because the new coloured molecules are too big to get out of the hair, the colour is 'trapped' or permanent until the hair grows or is naturally shed. These products tend to come in two separate containers inside the packet.
PPD is the hair dye most often associated with allergic reactions to hair colorant products. Sensitivity or allergy to PPD may develop over time, which is why an allergy alert test must be carried out each time the hair is to be coloured.
The safety of PPD has been extensively investigated over decades. The opinion of independent scientists across the world who have been asked to provide an official opinion on its safety is that PPD is safe for use as a hair dye. Its use is strictly regulated. At this time, PPD cannot be replaced in hair colorants: nothing else is as effective and it is safe when used as directed.
It is often mis-reported that PPD is banned in some European countries. This is not the case. PPD is allowed for use throughout the UK and EU according to the requirements of the respective laws.
PPD is sometimes illegally found in temporary skin tattoos. The use of PPD for this purpose is not authorised by UK cosmetics laws.
View more about temporary 'black henna' tattoos.
Download a factsheet about safe use of PPD in hair colorants.