UK SI 2026/23: The 2026 Chemical Substance Restrictions Explained
Share
Spectra Cosmetic Compliance
This sits within the wider UK cosmetics regime. Note: the regulatory position can change, so confirm the current detail before acting on any specific product.
What SI 2026/23 is
SI 2026/23 is the Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026 an amendment to the retained UK Cosmetics Regulation. It was laid before Parliament in January 2026 by the Office for Product Safety and Standards (OPSS), following a draft notified to the World Trade Organization in late 2025 and a short consultation, informed by advice from the UK's Scientific Advisory Group on Chemical Safety (SAG-CS).
It applies to cosmetic products placed on the Great Britain market England, Scotland, and Wales. Northern Ireland, under the Windsor Framework, continues to follow EU rules via Regulation (EC) No 1223/2009. SI 2026/23 is a clear example of the UK exercising its post-Brexit ability to set its own cosmetics rules broadly aligned with the EU, but on its own timeline.
The three main changes
SI 2026/23 makes three principal changes. It prohibits the UV filter 4-MBC (Enzacamene); it adds sixteen newly classified CMR substances to the list of substances banned in cosmetics; and it lowers the threshold for formaldehyde-releaser warning labelling dramatically. Each has its own deadline and its own implications, which we take in turn.
Together these changes affect a broad span of products sunscreens and SPF products, gel nail products, and any product using formaldehyde-releasing preservatives. Few brands with a UK range are entirely untouched, which is why understanding the instrument matters.
Change 1: The 4-MBC (Enzacamene) ban
SI 2026/23 prohibits 3-(4'-methylbenzylidene) camphor, commonly known as 4-MBC or Enzacamene a UV filter historically used in sunscreens and SPF products. It is added to the list of prohibited substances and removed from the list of permitted UV filters, following advice of a potential risk to human health.
The deadline: from 15 July 2026, products containing 4 MBC cannot be newly placed on the Great Britain market, with products placed before that date able to be supplied until 14 January 2027. Brands with SPF products should check their formulations for this UV filter. Our dedicated guide to the 4-MBC ban covers it in detail.
Change 2: Sixteen CMR substances banned
SI 2026/23 adds sixteen substances newly classified as CMR (carcinogenic, mutagenic or toxic for reproduction category 1B or 2 under the GB CLP Regulation) to the list of substances prohibited in cosmetics. These are banned regardless of concentration and span a range of chemical families, including organotin compounds, certain photoinitiators, industrial intermediates, and specific forms of carbon nanotubes.
The most notable for the beauty industry is TPO (trimethylbenzoyl diphenylphosphine oxide), a photoinitiator used in gel nail products. This deadline is 15 August 2026 for placing on the market. Our guide to the TPO ban covers the nail-sector impact specifically.
Change 3: Formaldehyde labelling threshold
SI 2026/23 dramatically lowers the threshold at which products must carry a formaldehyde warning from 0.05% down to 0.001% and changes the wording from products that 'contain' formaldehyde to products that 'release' it. This applies from 15 July 2026 and represents a major step-change in transparency for consumers sensitive to formaldehyde.
Because the threshold is now so much lower, many more products using formaldehyde releasing preservatives will need to carry the warning. This is primarily a labelling and compliance responsibility for brands and Responsible Persons. Our guide to the formaldehyde labelling change explains what it means in practice.
The deadlines summarised
There are two key placing on market dates. The 4 MBC ban and the formaldehyde labelling change apply from 15 July 2026. The CMR substance bans (including TPO) apply from 15 August 2026. Sell through (making available) periods extend into 2027 broadly to 14 January 2027 for 4 MBC and 14 February 2027 for the CMR substances.
These transitional arrangements give brands limited time to adapt, but the placing on market deadlines are firm. New products from the relevant dates must comply, and products already on the market can only continue to be supplied until the sell through deadlines. Confirm the exact dates and arrangements for your specific products, as detail matters.
What brands need to do
The practical response is a formulation review against SI 2026/23. Check whether any product contains 4 MBC, any of the sixteen newly banned CMR substances (notably TPO for nail products), or formaldehyde-releasing preservatives that now cross the lower labelling threshold. Where they do, plan reformulation or relabelling to meet the deadlines.
Affected products will also need their CPSR and PIF updated to reflect the changes, and labels revised where the formaldehyde warning now applies. This is exactly the kind of regulatory change that triggers reassessment of existing products. Acting well before the deadlines avoids a last-minute scramble or a gap in compliance.
How SI 2026/23 came about
SI 2026/23 did not appear without warning. A draft of the measures was notified to the World Trade Organization in late October 2025, followed by a short consultation period that closed in December 2025, before the instrument was laid before Parliament in January 2026. This gave industry visibility of the changes ahead of time, which is the normal pattern for significant cosmetics amendments.
The substance of the instrument was informed by opinions from the UK’s Scientific Advisory Group on Chemical Safety (SAG-CS), which assessed the safety of substances newly classified under the GB CLP Regulation. This reflects how ingredient regulation typically works: a chemical classification (such as a CMR designation) triggers a scientific assessment for cosmetic use, which in turn informs a regulatory decision to restrict or ban.
SI 2026/23 also illustrates the post-Brexit relationship between the UK and EU regimes. The EU had already moved on several of the same substances through its own amendments, and the UK’s instrument brings in broadly equivalent changes demonstrating an intent to remain broadly aligned while acting through its own process and on its own timeline. Alignment in direction does not mean identical dates, which is why each market still needs checking.
Could SI 2026/23 affect one of your cosmetic formulations? Spectra can review your ingredients and existing compliance documentation to identify affected products and help you prepare the necessary reformulation, relabelling, CPSR and PIF updates.
Frequently asked questions
What is SI 2026/23?
It is a January 2026 amendment to the UK Cosmetics Regulation for Great Britain. It bans the UV filter 4 MBC (Enzacamene) and sixteen newly classified CMR substances, and lowers the formaldehyde releaser warning labelling threshold to 0.001%.
When do the SI 2026/23 changes take effect?
The 4-MBC ban and the formaldehyde labelling change apply from 15 July 2026; the CMR substance bans (including TPO) apply from 15 August 2026. Sell-through periods for existing stock extend into early 2027.
Does SI 2026/23 apply across the whole UK?
No. It applies to Great Britain England, Scotland and Wales. Northern Ireland continues to follow EU cosmetics rules under the Windsor Framework.
What is 4-MBC and why is it banned?
4 MBC (Enzacamene) is a UV filter historically used in sunscreens. SI 2026/23 prohibits it and removes it from the permitted UV filters, following advice of a potential risk to human health. Products can't be newly placed on the GB market from 15 July 2026.
What CMR substances does it ban?
Sixteen substances newly classified as category 1B or 2 CMR under GB CLP, banned regardless of concentration from 15 August 2026. They include organotin compounds, photoinitiators such as TPO, industrial intermediates and certain carbon nanotubes.
What changed for formaldehyde labelling?
The threshold for the formaldehyde warning drops from 0.05% to 0.001%, and the wording changes from 'contains' to 'releases' formaldehyde, from 15 July 2026. Many more products using formaldehyde-releasing preservatives will now need the warning.
What should brands do about SI 2026/23?
Review formulations for 4 MBC, the banned CMR substances (notably TPO in nail products), and formaldehyde releasing preservatives near the new threshold. Reformulate or relabel as needed, update affected CPSRs and PIFs, and meet the deadlines.
How did SI 2026/23 come about?
A draft was notified to the World Trade Organization in late 2025, followed by a short consultation, before being laid before Parliament in January 2026. It was informed by the UK’s Scientific Advisory Group on Chemical Safety and brings in changes broadly equivalent to earlier EU moves.
References: The Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026, SI 2026/23 (legislation.gov.uk); OPSS guidance; UK SAG-CS opinions. Verified July 2026; confirm current detail before acting. General information only, not legal advice.