Earlier this year the Advertising Standards Agency (ASA) upheld a complaint from the UK beauty and personal care industry trade body Cosmetic, Toiletry & Perfumery Association (CTPA) about a hair colour product on the market that was claiming to be free from the chemical para-phenylenediamine free (PPD-free).
The product contained a related chemical, toluene-2,5 diamine sulphate (PTDS), which the CPTA said could also cause allergic reactions in consumers with PPD allergies, and therefore could still potentially cause a severe allergic reaction for someone with a sensitivity to PPD – in some cases causing anaphylaxis and posing an immediate risk to life.
When the ruling was made, the CTPA’s director-general Dr Emma Meredith said the ruling was welcome as it “underlined the importance of protecting allergic consumers from experiencing reactions, which can be very serious.”
By law the product must be correctly labelled
PPD itself is a widely used ingredient in permanent hair colourants. Although it is not always present in hair colour products, PPD or related ingredients such as PTD, MePPD or other derivatives can often be present in darker hair colourant shades.
As a result, after the ruling, the CTPA issued a warning to cosmetic manufacturers about making claims about PPD-free hair colours, noting that if a hair colourant contains PPD, or a related hair dye, by law the product also has to be labelled with “Contains phenylenediamines” or “Contains phenylenediamines (toluenediamines)” to alert users with a PPD allergy that the product is unsuitable for them.
These alternatives can produce a similar type of reaction in people who have the potential to become sensitised to the ingredient, and there can be cross-reactivity to both hair dyes. This means that someone who is allergic to PPD is also likely to react to PTDS and other derivatives, even if they have not used them before.
According to the CEO of TrichoCare Diagnostics, Nick Plunkett, this could be an industry-wide issue that spread further than the actions of one company.
“Following on from news that the CTPA has issued a warning to cosmetic manufacturers about making claims about PPD-free hair colours, a team of US scientists tested 51 best-selling hair colours and they found PPD in four “PPD-Free” colours and one contained more than the legal limit,” he said.
“Seven of the products contained allergens that were not listed on the ingredients. It is a legal requirement in the EU and US to label all ingredients used in cosmetics, as per Article 19, the EU rules are based on US rules.”
PTDS dubbed ‘Contact Allergen of the Year 2025’
Plunkett also said that the names of products are not published, and that this is not the first study of its kind.
For him, the real dangers associated with PPD are the development of allergy and a subsequent allergic reaction. “These latest observations are important as an individual with allergy will not be aware that the hair dye they are using contains the substance to which they are allergic,” he said.
He also highlighted that the hair colour ingredient PTDS has been named ‘Contact Allergen of the Year 2025’ by the American Contact Dermatitis Society
“This is one of a list of cross-reacting chemicals used in colour formulations as a replacement to PPD,” he explained.
To conclude, for hair colour manufacturers Plunkett echoed the advice of the CTPA. “As well as having to be listed in the ingredients list on pack, when a hair colourant contains PPD, or a related hair dye, by law the product also has to be labelled with ‘Contains phenylenediamines’ or ‘Contains phenylenediamines (toluenediamines)’ to alert users with a PPD allergy that the product is unsuitable for them,” he said.