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UK Amends Cosmetics Regulation with New Ingredient Prohibitions and Restrictions (SI 2026/23)
On 15 January 2026, the UK Government laid before Parliament a significant amendment to the retained UK Cosmetics Regulation. The Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026, known as SI 2026/23, introduces sweeping changes that will affect formulations, labelling, and market access for cosmetic products sold in Great Britain.
For brands operating in the GB market, this is one of the most impactful regulatory updates since Brexit. Understanding the new prohibitions, the revised labelling threshold, and the phased compliance deadlines is essential to avoid enforcement action and maintain uninterrupted market access.
Background: How the UK Cosmetics Regulation Works Post-Brexit
Since Brexit, the United Kingdom has maintained the core framework of EU Regulation (EC) No 1223/2009 but operates its own independent regime for England, Wales, and Scotland. The UK Office for Product Safety and Standards (OPSS) is responsible for updating the Annexes to reflect new scientific evidence and hazard classifications under the GB CLP Regulation (EC) No 1272/2008.
A draft of SI 2026/23 was notified to the World Trade Organization (WTO) on 31 October 2025 under reference G/TBT/N/GBR/107. Following a public consultation that closed in December 2025, the final instrument was laid before Parliament in January 2026. The proposals were informed by opinions from the UK’s Scientific Advisory Group on Chemical Safety (SAG-CS).
While the UK is no longer required to mirror EU changes, SI 2026/23 demonstrates a clear intent to remain broadly aligned on chemical safety outcomes while setting its own timelines and labelling thresholds.
Three Key Changes Introduced by SI 2026/23
The regulations introduce three interconnected changes that collectively create urgency for cosmetics brands selling in Great Britain.
1. Complete Ban on 4-MBC (Enzacamene)
4-Methylbenzylidene Camphor (4-MBC), also known as enzacamene (CAS No. 38102-62-4 / 36861-47-9), is added to Annex II of the UK Cosmetics Regulation, making it a prohibited substance. Previously permitted as a UV filter component in sunscreen formulations, 4-MBC may no longer be used in cosmetic products placed on the GB market from 15 July 2026.
Products already on the market before this date benefit from a transitional sell-through period until 15 January 2027. This ban aligns with the EU’s position, effectively allowing brands to maintain a single formulation for both markets.
Brands using 4-MBC in sunscreen products should immediately identify alternative UV filters permitted in the UK and begin reformulation, including stability, compatibility, and performance testing.
2. Prohibition of 16 CMR Substances
Sixteen additional substances classified as carcinogenic, mutagenic, or reprotoxic (CMR) under the GB CLP Regulation are now added to Annex II. These substances may not be used in cosmetic products placed on the market from 15 August 2026, with a sell-through deadline of 15 February 2027.
The newly prohibited substances include:
- Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) — widely used in nail curing systems
- Clothianidin
- Dimethyl propylphosphonate
- Dibutyltin maleate and Dibutyltin oxide
- Tetrabromobisphenol-A
- 1,4-Benzenediamine, N,N’-mixed Ph and tolyl derivatives — relevant to hair dyes and colour cosmetics
- 4-Methylimidazole
- Acetone oxime
- Benthiavalicarb isopropyl 2,3-epoxypropyl neodecanoate
- Multi-Walled Carbon Nanotubes (MWCNTs)
- 7-Oxabicycloheptanyl esters
- Dimethylamino-methyl-morpholino phenyl butanone derivatives
- S-metolachlor and related isomers
- Trimethyl borate
For the nail care industry, the prohibition of TPO is particularly significant. Brands using these substances must review formulations and supplier documentation, including checking for the presence of these chemicals as trace impurities.
3. Formaldehyde Labelling Threshold Lowered to 0.001%
Perhaps the most far-reaching change for cosmetics labels is the amendment to Annex V concerning formaldehyde-releasing preservatives. Previously, the warning phrase “releases formaldehyde” was required where free formaldehyde exceeded 0.05% in the finished product. Under SI 2026/23, this threshold is reduced to 0.001% (10 ppm).
This represents a fifty-fold reduction and will affect a wide range of products containing preservatives listed in Annex V. Safety assessors must verify updated calculations for formaldehyde content, and labels must be amended for products placed on the market from 15 July 2026.
Compliance Deadlines at a Glance
| Date | Requirement | Type |
|---|---|---|
| 15 July 2026 | 4-MBC ban and formaldehyde labelling threshold take effect | Placing on market |
| 15 August 2026 | 16 new CMR substance prohibitions take effect | Placing on market |
| 15 January 2027 | Sell-through deadline for 4-MBC and formaldehyde labelling | Off-shelf |
| 15 February 2027 | Sell-through deadline for CMR-banned substances | Off-shelf |
What’s Coming Next: The Second WTO Notification
On 27 November 2025, OPSS notified the WTO of a separate proposed draft amendment (No. 2 Regulations 2026) that would introduce further changes to both Annex II and Annex III. This draft proposes adding 13 additional CMR substances to the prohibited list, including silver (nano), ozone, dinitrogen oxide, and α-methylstyrene.
These substances would be prohibited from 23 March 2027, with an off-shelf deadline of 22 September 2027. The same draft also introduces restrictions on hexyl salicylate in Annex III, with defined concentration limits for different product categories and target populations.
Recommended Actions for Cosmetics Brands
With compliance dates approaching rapidly, brands should take the following steps:
- Formulation audit: Review all product formulations against the updated Annex II prohibited list. Check for 4-MBC, TPO, and all 16 newly banned CMR substances, including as trace impurities from raw materials.
- Formaldehyde assessment: Recalculate free formaldehyde levels in all products containing Annex V preservatives. At 0.001%, the new threshold may trigger labelling requirements for formulations previously considered compliant.
- Label updates: Amend product labels to include the “releases formaldehyde” warning where required. Ensure all label changes are in place before 15 July 2026.
- PIF updates: Update safety assessments, stability data, and ingredient documentation in all affected Product Information Files.
- Reformulation planning: For products containing 4-MBC, identify alternative UV filters and plan for reformulation testing well ahead of the July 2026 deadline.
- Transition calendar: Build a compliance calendar aligned with the phased enforcement dates and coordinate with supply chain partners.
- Monitor upcoming amendments: Track the No. 2 Regulations 2026 draft for 13 further substance prohibitions and hexyl salicylate restrictions.
How CosmeReg Can Help
Navigating the UK’s evolving cosmetics regulatory landscape requires specialist knowledge. CosmeReg supports brands with formulation audits, ingredient compliance reviews, labelling updates, safety assessments, and ongoing regulatory monitoring for the GB market.
Contact our team to discuss your compliance strategy ahead of the 2026 deadlines.
Published: February 2026 | Last updated: February 2026
Source: SI 2026/23 — The Cosmetic Products Regulation (EC) No 1223/2009 (Restriction of Chemical Substances) (Amendment and Transitional Provisions) Regulations 2026; WTO Notification G/TBT/N/GBR/107.
Pasquale Carvelli is a Regulatory Strategy & International Compliance Advisor for Cosmereg, an international regulatory affairs company supporting manufacturers, distributors, and brand owners navigating complex compliance frameworks across multiple jurisdictions.
Through a multidisciplinary network of certified safety assessors and regulatory experts, he oversees strategic compliance pathways for cosmetic, food, and supplement products entering regulated markets.
