PPD is one of the most talked-about ingredients in professional hair colour, and one of the most misunderstood. You may have heard that PPD is banned, that "PPD-free" colour can't cause an allergy, or that someone who has coloured their hair for years without a problem doesn't need to worry. None of those statements gives the full picture.
Key takeaways
- PPD is not banned. It is permitted in oxidative hair colour, with strict limits and warnings set in law.
- PPD is a known contact allergen. Anyone can become sensitised, even after years of problem-free colour.
- "PPD-free" does not mean "allergy-free".
- Always follow the manufacturer's Allergy Alert Test instructions, and take any past reaction seriously, including to black henna tattoos.
- Hairdressers educate and refer. They don't diagnose.
What is PPD?
PPD stands for p-phenylenediamine. It is an oxidative dye ingredient used in permanent hair colour.
Oxidative colour works through a chemical reaction between dye precursors and an oxidising agent, usually hydrogen peroxide, which develops the colour inside the hair. This chemistry is what gives professional permanent colour its lasting results and reliable grey coverage.
Is PPD banned?
No. In the UK and EU, PPD is allowed in oxidative hair colour, but only under strict conditions set out in the cosmetics regulations. After mixing, the concentration applied to the hair must not exceed 2% (calculated as free base), and the label must carry warnings. These include that hair colorants can cause severe allergic reactions, that the product is not intended for people under 16, and that temporary "black henna" tattoos may increase the risk of allergy (Regulation (EU) No 1197/2013, amending Annex III of the Cosmetics Regulation).
That doesn't mean we should dismiss concerns about PPD. It is a known contact allergen, and some people become sensitised and go on to react. This is exactly why professional colour safety procedures matter.
Allergy and irritation aren't the same thing
The two words are often used interchangeably, but they describe different things:
- Irritation happens when something directly irritates the skin.
- An allergic reaction involves the immune system responding to a substance the person has become sensitised to.
For a hairdresser, the important point is not to try to work out which one has happened. If a client has a suspected reaction, take it seriously and follow the appropriate professional and medical guidance.
"I've coloured my hair for 20 years and I've always been fine"
Hairdressers hear this all the time. Unfortunately, years of problem-free colour don't guarantee that someone will never develop an allergy, because sensitisation can build up after previous exposure.
That's one reason following the manufacturer's Allergy Alert Test instructions still matters, even for long-standing colour clients.
What is an Allergy Alert Test?
An Allergy Alert Test is designed to help identify whether a client might react to a hair colour product before the full colour service goes ahead.
Each manufacturer gives specific instructions on how and when their test should be carried out. Follow the instructions supplied with the colour you're using, rather than creating your own testing routine.
Does PPD-free mean allergy-free?
No, and this is one of the most important misconceptions to clear up. Removing one known allergen doesn't make a product incapable of causing a reaction. Other oxidative dye ingredients are used in colour, and people can be allergic to other substances too.
"PPD-free" tells you something specific about the formula. It is not a guarantee that nobody can react to it.
What replaces PPD, and is it better?
Most "PPD-free" permanent colours replace PPD with a closely related dye ingredient. The two you'll see most often on ingredient lists are:
- PTD, listed as toluene-2,5-diamine or toluene-2,5-diamine sulfate. This is the most common alternative.
- ME-PPD, listed as 2-methoxymethyl-p-phenylenediamine. This is a newer version of the PPD molecule, designed to be less sensitising.
So is it better? For some people, yes, but neither is a guaranteed fix. PTD is itself a known allergen, and studies show around 30–50% of people allergic to PPD also react to PTD (American Academy of Dermatology). ME-PPD performs better: in studies of 73 PPD-allergic people under hair dye use conditions, 62% did not react to ME-PPD and another 18% had a weaker reaction (published research review). That still means some people react.
Professional colour ranges also differ shade by shade. In Eva Professional's permanent colour, for example, some shades use PPD and others use PTD, so always check the ingredient list for the specific shade you're using. Some newer colour technologies are marketed as PPD-free too, and we'll look at those in a future post.
The key point: anyone with a known or suspected PPD allergy shouldn't simply switch to a "PPD-free" colour. They should get advice from a dermatologist, and the manufacturer's Allergy Alert Test instructions still apply.
What about black henna tattoos?
So-called black henna temporary tattoos have been linked to high exposure to PPD, which is why UK and EU law requires hair colour labels to warn about them.
Anyone who has reacted to a black henna tattoo should tell their hairdresser before having oxidative colour. It's another reason a thorough consultation matters.
What should salons take from this?
We don't need fear around professional hair colour. We need good practice. Hairdressers should:
- Follow the manufacturer's safety instructions
- Carry out Allergy Alert Testing where instructed
- Take previous reactions seriously
- Ask the right questions during consultation
- Keep clear client records
- Avoid making medical diagnoses
- Refer clients for medical advice where appropriate
Professional colour is chemistry, and understanding that chemistry helps us use it responsibly.
Better education creates safer conversations
Clients increasingly arrive with information from TikTok, Instagram, Google and online ingredient checkers. Some of it is useful; some of it is missing important context.
Our job as professionals isn't to dismiss people's concerns. It's to understand our products well enough to explain what we know, recognise the limits of our role, and follow the safety guidance supplied with the products we use.
PPD isn't a subject we need to be frightened of discussing. It's a subject we need to understand.
Keep learning
Want colour and product education for your team? Savvy & Shine offers technical training on the professional colour ranges we supply.
This article is general professional education and isn't medical advice. Anyone with a suspected reaction to hair colour should seek advice from a pharmacist, GP or dermatologist.