What changed for head spa therapists, stylists and cosmetic practitioners in 2025, from straightener chemistry to licensing plans, and the education that follows.
From the editors
This edition looks back at 2025 from the salon chair and the head spa bed. It is part of our Four years in review series, written in 2026; Trichozette did not exist in 2025, and we are not pretending otherwise. What we have done is gather the developments that mattered to cosmetic practitioners that year and check each one against its source.
Two themes stand out. The first is chemistry: a French safety agency warned about glyoxylic acid in straightening products, and the European Union banned the nail-gel ingredient TPO. The second is scope: England and Scotland both set out how non-surgical cosmetic procedures would be regulated, with training, insurance, premises and age limits at the centre.
Neither theme is about head spa or hairdressing alone, and that is the point. Cosmetic practitioners work closer to the scalp than almost anyone, and the rules around them are tightening. The best preparation is sound education: knowing your products, knowing your limits and knowing whom to call.
The Trichollective editorial team
Products
Two chemical stories from 2025 carry the same lesson for anyone who applies products to a client's hair or scalp: availability is not the same as assessment.
Photograph Todd Trapani / Unsplash
Words by the Trichollective editorial team
In January 2025 the French Agency for Food, Environmental and Occupational Health and Safety, ANSES, published an opinion on hair-straightening products containing glyoxylic acid. It concluded that it is highly probable that the substance can cause acute kidney injury, likely by passing through the scalp into the bloodstream and forming calcium oxalate crystals in the kidney.
ANSES advised against using straightening products that contain glyoxylic acid and called for an assessment at European level that could limit or prohibit it. At the time, glyoxylic acid had never been assessed by the EU and was not regulated in European cosmetics. Reporting on the opinion noted that Israel had banned the substance in 2022 after documenting cases of kidney injury.
From 1 September 2025, trimethylbenzoyl diphenylphosphine oxide, known as TPO, was prohibited in all cosmetic products in the European Union. TPO helps UV nail gels and hybrid polishes harden under a lamp. It had previously been permitted for professional use only, but its classification as a CMR substance, one that may cause cancer, genetic damage or harm to reproduction, triggered a full ban. Ireland's HPRA told salons to check ingredient lists, stop using affected products and dispose of stock; there was no period to use up old supplies. Great Britain has a separate system for cosmetics and set its own timetable.
“A product being on sale does not settle whether it is safe for every client or every setting.
None of this requires a cosmetic practitioner to become a toxicologist. It requires the habit of checking. When a client asks whether a treatment is safe, the honest answer is often that it has been sold widely, that the manufacturer's precautions must be followed, and that regulators are still reviewing some ingredients.
Test yourself
Why was TPO banned in EU cosmetics from 1 September 2025?
Sources
Every fact in this edition, and where it came from.
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