Articles about PPD allergy are among the most popular on this website, especially the listing of PPD-free hair dye and colour alternatives, which showcases the wide variety of options you can try if you are sensitive to the chemical para-phenylenediamine, or related chemicals, or are concerned about using them.
If you’ve landed here looking for product suggestions, the link above is for you.
What does a PPD-free claim on a product mean?
This question often arises.
In February 2025, the UK’s Advertising Standards Authority (ASA) ruled against the makers of Natur Vital (included in our round-up linked to above) for marketing their products as “PPD-free” when they contained PTDS, a similar compound that can cause similar allergic reactions in PPD-sensitized individuals.
According to the CTPA, hair dyes must explicitly declare they contain PPD and related compounds, and not make a PPD-free claim unless free of all of them. (Read their updated position statement here.)
PTDS, also known as toluene-2,5-diamine sulfate, was this year named Allergen of the Year by the American Contact Dermatitis Society (ACDS), in order to highlight particularly problematic or often overlooked skin allergens which deserve attention.
This was almost twenty years after PPD earned itself the same dubious honour.
Is there a safe permanent hair dye?
Previous research suggests that a new ‘gentler’ molecule, called ME-PPD (2-methoxymethyl-p-phenylenediamine), is tolerated by 67% of PPD-allergic individuals, but some still experienced reactions. I wrote about this at the time.
Clinical trials are ongoing to evaluate new compounds (PPD-6 and PPD-7) for reduced cross-reactivity with PPD in sensitized patients. Early research trials suggest they have weaker sensitization potential — around 22% for PPD-6 and 23.8% for PPD-7, compared to 55.5% for PPD.
In the absence of safer alternatives to oxidative permanent hair dyes, we must keep emphasising the importance of avoidance if you have ever reacted or patch tested positive to PPD or related chemical.
If you haven’t, but have lots of contact allergies or are particularly atopic, it may be worth abstaining completely, to be on the safe side.
If you are committed to dying your hair, you must perform an open application test every time — detailed instructions will be included in the hair dye kit you purchase.
And another point to emphasise is to avoid black henna when abroad. See here for more information.
Be especially careful with products sourced from outside Western jurisdictions — see here, for reasons why. Always buy from trusted local sources from brands with good reputations and standards.