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If you’re a salon owner or beauty pro, you’ve probably seen talk about the 2026 UK cosmetics regulation changes, especially the TPO ban for nail products.
But TPO is just one piece of a bigger update for our industry.
SI 2026/23 brought in a few key changes for salons in Great Britain: 16 new banned ingredients (including TPO), a ban on the UV filter 4-MBC, and a lower threshold for when products need a formaldehyde warning label.
If you’re wondering what this means for the products on your shelves, there’s one more thing to keep in mind:
Not every change has the same deadline.
Depending on the ingredient or rule, you’ll see different key dates: 15 July and 14 January, or 15 August and 14 February.
Here’s what actually matters for salon pros.
What Is SI 2026/23 and What Does It Ban?
“SI 2026/23” is simply the abbreviated name for Statutory Instrument 2026 No. 23.
Its full title is The Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026.
The legislation amends the rules governing cosmetic products in Great Britain – England, Scotland and Wales.
For salon professionals, three areas are particularly relevant:
- 16 substances classified as CMRs were added to the prohibited substances list in Annex II, including TPO.
- The UV filter 4-MBC was prohibited.
- The threshold at which relevant products must carry the warning “releases formaldehyde” was reduced from 0.05% to 0.001%.
You don’t need to be a legal expert to keep your salon safe and compliant.
What matters is knowing which changes affect your products, when the deadlines hit, and what to check on your shelves.
The 16 newly classified CMR substances
One part of SI 2026/23 adds 16 CMR substances to Annex II of the Great Britain Cosmetics Regulation, meaning they're prohibited for use in cosmetic products.
CMR stands for substances classified as carcinogenic, mutagenic or toxic for reproduction.
That might sound worrying, but here’s what salon pros really need to know.
CTPA says that, of these 16 substances, TPO is the one with an INCI name that is used in cosmetic products.
So you don’t need to stress about memorising 16 chemical names or checking every single bottle in your salon.
For most of us, TPO is the main ingredient to focus on.
TPO: the most relevant ban for nail and gel professionals
TPO – Trimethylbenzoyl Diphenylphosphine Oxide – is a photoinitiator that has been used in some UV and LED-curable nail products.
Its role is essentially to help start the chemical reaction that allows the product to cure when exposed to the appropriate light.
Under SI 2026/23, TPO has now been added to Annex II and is prohibited for use in cosmetic products in Great Britain.
This is particularly relevant if you work with:
- gel polish
- builder gels
- enhancement gels
- other UV/LED-curable nail systems.
Not every gel product contains TPO. Formulas vary, and lots of pro brands already have TPO-free options.
Related Products
If you're a nail professional, we've covered the ingredient, existing stock rules and transition in much more detail in our TPO nail ingredient ban: full update.
And you maybe interested in our previous post 'BIAB and Builder Gel: The professional guide'
4-MBC: the UV filter ban and what it affects
SI 2026/23 also prohibits 4-methylbenzylidene camphor (4-MBC), which has been used as a UV filter in cosmetic products.
4-MBC was added to Annex II and removed from Annex VI, the list of permitted UV filters.
Importantly, 4-MBC doesn't have the same transition dates as TPO.
For 4-MBC:
15 July 2026 was the placing-on-market deadline.
14 January 2027 is the making-available or “off-shelf” deadline.
You don’t need to figure out the legal status of every ingredient yourself.
Check your product info and current stock, buy from trusted pro suppliers, and reach out to the brand or supplier if you’re unsure about a product.
The Deadlines: What Each One Means for Your Business
This is the part you really want to get right.
You'll see four dates associated with SI 2026/23 because different changes have different transitional periods.
| Change |
Placing on the market
|
Must be off the shelves by
|
| 4-MBC prohibition |
15 July 2026
|
14 January 2027
|
| Formaldehyde warning threshold |
15 July 2026
|
14 January 2027
|
| 16 CMR substances, including TPO |
15 August 2026
|
14 February 2027
|
These are the dates confirmed in CTPA's published guidance.
So if you see someone mention “the 2026 cosmetics deadline,” double-check which rule or ingredient they mean.
15 August 2026: the placing-on-market deadline for TPO and the 16 CMR substances
For the 16 CMR substances added to Annex II, including TPO, the placing-on-market deadline was 15 August 2026.
That deadline has now passed.
In practice, you can’t buy or sell new stock with those banned ingredients in Great Britain anymore.
But that doesn’t mean every product already in the supply chain had to vanish overnight on 15 August.
A transitional period applies to products that had already been legally placed on the market.
14 February 2027: the off-shelf deadline
For these 16 CMR substances, the next important date is 14 February 2027.
Products containing these substances that were legally placed on the market before the August deadline can continue to be made available during the transitional period.
After the making-available deadline, distributors will no longer be able to supply products containing the banned ingredients.
What can you do with stock bought before August 2026?
This is where it matters whether you’re selling a product or just using it in your salon services.
CTPA's current interpretation of the Great Britain Cosmetics Regulation is that professionals may continue using products containing banned ingredients on clients after the making-available deadline, provided they already purchased that stock.
They cannot purchase further affected products from distributors after the relevant making-available date.
CTPA says it has discussed this interpretation with Trading Standards and that both are aligned on the position.
So, for example, current GB guidance means a nail technician doesn't automatically have to throw away a TPO gel they lawfully purchased simply because 14 February 2027 arrives.
This is an important difference from the stricter interpretation you've possibly seen discussed in relation to EU rules.
For salons, don’t rush to throw out your pro stock just because you saw a headline or an EU article. Always check which country and deadline the info is about.
Guidance last checked: 9 September 2026.
Which Product Categories Are Affected in a Salon Setting?
SI 2026/23 is a general cosmetics update, not a salon-specific rule, so there’s no simple list of “banned salon products.”
The products most relevant to salon professionals depend on the particular part of the legislation.
Nail products: TPO is the most significant change for nail professionals because it has been used in some UV/LED-cured nail systems, including some gel and builder products.
Products with UV filters: 4-MBC is a UV filter, so check with your manufacturer or supplier before assuming every UV-protective product is affected.
Cosmetics with formaldehyde-releasing preservatives: these aren’t banned, but the 2026 update means the warning label now applies at a much lower level.
That last distinction is particularly important.
The formaldehyde update is a labelling change, not the same thing as the TPO and 4-MBC prohibitions.
You can read our full guide to the formaldehyde labelling rules for salon products for the ingredients and product categories to check.
How to Check If Your Products Are Compliant
You don’t need a chemistry degree to check your salon shelves.
A smart stock check looks like this:
- Identify the products most likely to be relevant. If you're a nail technician, start with your UV/LED-cured nail products and check for TPO.
- Read the INCI list. For TPO, look for Trimethylbenzoyl Diphenylphosphine Oxide.
- Don’t just go by the product name. Brands update formulas all the time, so two bottles that look the same might have different ingredients.
- Check current manufacturer information. If a product has recently been reformulated, establish which version you actually own.
- Hang on to your purchase and batch info if you can. It helps show when and where your stock came from. Ask when you're uncertain. Your supplier or manufacturer should be able to clarify the status of an individual professional product.
If you're not confident interpreting cosmetic ingredient labels, our guide to how to read an INCI list for banned ingredients takes you through the process step by step.
The main thing is to check the actual product you have, not just assume a whole brand or category is fine (or not) because of something you saw on social media.
TPO-Free and Compliant Alternatives Are Already Available
If you find some of your nail stock has TPO, there’s no need to swap out your whole kit in one go.
Professional brands have already introduced TPO-free formulations across categories such as gel polish and builder gel.
As you run out of products, just start switching to compliant alternatives and follow the latest guidance for what you already have.
When you switch to a new or reformulated nail system, remember that TPO-free doesn’t always mean you can use it exactly like your old products.
Always check the manufacturer’s instructions for application, lamp compatibility, and curing times.
What About the Formaldehyde Labelling Change?
Although the main focus around SI 2026/23 has understandably been TPO, the legislation also introduced an important change affecting formaldehyde-releasing preservatives.
Previously, relevant finished cosmetic products needed the warning “releases formaldehyde” where the concentration of released formaldehyde exceeded 0.05%.
That threshold has now fallen to 0.001%.
For this particular change, the placing-on-market deadline was 15 July 2026, with the transitional making-available deadline on 14 January 2027.
This doesn’t mean products with a formaldehyde-releasing preservative are suddenly banned.
It just changes when the warning label needs to be shown on the finished product.
That's why checking which part of SI 2026/23 you're reading about matters: TPO, 4-MBC and formaldehyde-releasing preservatives are not all subject to exactly the same regulatory requirement.
For a closer look at the updated labelling requirements, read our Formaldehyde in Salon Products guide.
FAQ: UK Cosmetics Regulation 2026
What is SI 2026/23?
SI 2026/23 is the statutory instrument that amended parts of the cosmetics regulations applying in Great Britain in 2026.
Among its changes, it prohibited 16 newly classified CMR substances, including TPO, prohibited the UV filter 4-MBC and changed the warning threshold for cosmetics containing formaldehyde-releasing preservatives.
What does CMR mean?
CMR refers to substances classified as carcinogenic, mutagenic or toxic for reproduction.
SI 2026/23 added 16 CMR substances to Annex II of the Great Britain Cosmetics Regulation. CTPA identifies TPO as the substance within that group with an INCI name that is used in cosmetic products.
Which products are most relevant to salons?
For nail professionals, TPO is particularly relevant because it has been used in some UV/LED-curable nail products.
SI 2026/23 also affects 4-MBC, previously used as a UV filter, and changes labelling requirements for products containing formaldehyde-releasing preservatives.
Can I still use existing TPO stock after 15 August 2026?
Under current CTPA guidance for Great Britain, yes. CTPA says professionals may continue using affected products on clients, while the making-available deadline determines how long distributors can continue supplying qualifying existing stock.
Do I have to throw away TPO products on 14 February 2027?
Under CTPA's current GB interpretation, no. Professionals may continue using products they have already purchased after the making-available deadline, although distributors cannot continue supplying them after that deadline. CTPA says Trading Standards is aligned with this interpretation.
Are all of the SI 2026/23 deadlines in February 2027?
No.
For the 16 CMR substances including TPO, the making-available deadline is 14 February 2027.
For 4-MBC and the new formaldehyde warning threshold, the corresponding deadline is 14 January 2027.
Does SI 2026/23 apply to Northern Ireland?
The changes discussed here concern the Great Britain cosmetics regime, covering England, Scotland and Wales. Northern Ireland follows the relevant EU cosmetics framework.
What Salon Professionals Should Do Now
The key thing about SI 2026/23 isn’t memorising the law.
It's knowing what to do with the products in front of you.
For most salon pros, that means checking your stock, knowing which deadlines matter, reading ingredient lists, and moving to compliant alternatives as you restock.
If you're a nail professional, pay particular attention to TPO/Trimethylbenzoyl Diphenylphosphine Oxide.
If you're reviewing other cosmetic products, remember that 4-MBC and the formaldehyde-labelling change have different dates from TPO.
And don’t throw out your pro stock just because you saw a headline about a “banned” ingredient. In Great Britain, it matters whether you’re buying, selling, or just using stock you already own.
Guidance last checked: 9 September 2026.
For current regulatory information, see the CTPA's published summary of the UK Cosmetics Regulation amendments and its guidance on professional use of existing stock.
This article provides general information for salon and beauty professionals and does not constitute legal or regulatory advice.
