+34 603 445 673 
On 12 January 2026, the UK government adopted Statutory Instrument SI 2026/23 – officially “The Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026” -, introducing targeted amendments to the retained version of Regulation (EC) No 1223/2009 on cosmetic products as it applies in Great Britain.
This new instrument focuses on chemical safety, specifically the treatment of CMR substances, formaldehyde-releasing ingredients, and one UV filter, reinforcing the UK’s post-Brexit approach to cosmetic risk management. The changes are legally binding and include defined entry-into-force dates and transitional periods, giving brands limited time to adapt.
Key regulatory changes introduced by SI 2026/23
SI 2026/23 amends the GB Cosmetics Regulation, which continues to mirror the structure of the EU framework while evolving independently. The measures apply to cosmetic products placed on the market in Great Britain, meaning England, Scotland and Wales. Northern Ireland remains aligned with EU cosmetic legislation under the Windsor Framework.
The instrument primarily updates Annex II (list of prohibited substances) and Annex III (restricted substances with conditions of use).
Prohibition of Enzacamene (4-MBC)
One of the most visible changes is the prohibition of 3-(4-methylbenzylidene) camphor, also known as enzacamene (4-MBC), a UV filter historically used in sunscreen formulations.
From 15 July 2026, 4-MBC may no longer be used in cosmetic products placed on the Great Britain market. It is removed from the list of permitted UV filters and added to the list of prohibited substances, reflecting concerns related to its toxicological profile.
Products already placed on the market before that date may continue to be made available during the transitional period, provided they comply with the rules applicable at the time of placement.
New labelling threshold for formaldehyde-releasing substances
SI 2026/23 also introduces a significant change to labelling requirements for formaldehyde-releasing ingredients.
The warning “contains formaldehyde” will now be required when a cosmetic product releases formaldehyde at concentrations equal to or above 0.001 percent, replacing the previous higher threshold.
This change strengthens consumer information obligations and has practical implications for preservatives and raw materials that may release formaldehyde as a by-product, even at very low levels. Compliance will require reassessment of formulations, supplier documentation and product labels.
Addition of new CMR substances to Annex II
The core of SI 2026/23 is the addition of a full set of substances classified as carcinogenic, mutagenic or toxic for reproduction (CMR) under the GB CLP Regulation to Annex II, making them prohibited in cosmetic products.
These substances are mainly classified as category 1B or category 2 CMRs and cover a wide range of chemical families, including organotin compounds, certain photoinitiators, industrial intermediates and specific forms of carbon nanotubes.
From 15 August 2026, cosmetic products placed on the Great Britain market must not contain any of these substances, regardless of concentration.
Transitional provisions and sell-through periods
To allow economic operators to adapt, SI 2026/23 introduces clear transitional timelines:
Products containing 4-MBC or subject to the former formaldehyde labelling threshold may continue to be made available until 14 January 2027, provided they were placed on the market before the applicable prohibition date.
Products containing the newly prohibited CMR substances may remain available until 14 February 2027, again only if they were placed on the market before 15 August 2026.
After these dates, non-compliant products must be withdrawn.
Regulatory implications and enforcement considerations
SI 2026/23 is not a purely administrative update. It directly affects:
- Formulation strategies, especially for sun care and preserved products
- Ingredient screening against updated Annex II
- Label content and warning statements
- Product Information Files and safety assessments
- Stock management and market withdrawal planning
For brands operating across multiple markets, the divergence between EU and UK cosmetic rules also becomes more visible, reinforcing the need for market-specific compliance strategies rather than a single harmonised approach.
Preparing for compliance in Great Britain
With staggered application dates starting in mid-2026, preparation cannot be delayed. The timeline below defines the key regulatory milestones brands must align with:
- 15 July 2026
From this date, it will no longer be permitted to place on the UK market cosmetic products containing 4-MBC or products relying on the former formaldehyde labelling threshold. - 14 January 2027
End of the transitional period for those products. Items placed on the market before 15 July 2026 may remain available only until this date. After this point, non-compliant products must be withdrawn. - 15 August 2026
Prohibition of placing on the market cosmetic products containing the newly classified and prohibited CMR substances introduced under SI 2026/23. - 14 February 2027
End of the transitional period for affected CMR products. Products placed on the market before 15 August 2026 may remain available only until this date.
How Cosmeservice Supports Cosmetic Brands
At Cosmeservice, we support cosmetic brands operating in the UK by evaluating ingredient compliance against updated Annexes, reviewing formulations affected by new CMR classifications or formaldehyde-release thresholds, and supporting the update of product documentation and labelling in line with Great Britain requirements. We also work closely with the UK Responsible Person to ensure a coordinated and compliant market strategy, particularly for brands managing multi-market portfolios with diverging EU and UK rules.
If you need support assessing the impact of SI 2026/23 on your products or preparing for the upcoming deadlines, you can contact us at
info@cosmeservice.com
References
FAQs
What is UK SI 2026/23?
SI 2026/23 is the Statutory Instrument that amends the retained UK version of Regulation (EC) No 1223/2009 on cosmetic products. It introduces new CMR substance prohibitions, bans the UV filter enzacamene (4-MBC), and lowers the labelling threshold for formaldehyde-releasing ingredients in products placed on the Great Britain market.
When does the 4-MBC ban take effect in the UK?
4-MBC (enzacamene) can no longer be used in cosmetic products placed on the Great Britain market from 15 July 2026. Products already on the market before that date may continue to be sold through until 14 January 2027.
What is the new formaldehyde labelling threshold under SI 2026/23?
From the entry into force of SI 2026/23, the warning “contains formaldehyde” is required when a cosmetic product releases formaldehyde at concentrations equal to or above 0.001%, replacing the previous, higher threshold.
When must CMR-restricted cosmetic products be withdrawn from the Great Britain market?
Cosmetic products containing the newly prohibited CMR substances cannot be placed on the market from 15 August 2026. Products already placed on the market before that date may remain available until 14 February 2027, after which they must be withdrawn.
Does SI 2026/23 apply in Northern Ireland?
No. SI 2026/23 applies only to Great Britain (England, Scotland and Wales). Northern Ireland remains aligned with EU cosmetic legislation under the Windsor Framework, so brands selling in both markets need separate compliance checks.
