UK SAG-CS Opinions On OPP And Sodium OPP In Cosmetics 2026: Safety, Concentration Limits & UK Cosmetics Compliance Guide

UK Scientific Advisory Group Reviews o-Phenyl phenol and Sodium o-Phenyl phenate Following Carcinogenicity Classification

The UK regulatory landscape for cosmetic preservatives continues to evolve as scientific safety assessments increasingly influence the future status of cosmetic ingredients.

The UK Scientific Advisory Group on Chemical Safety of Non-Food and Non-Medicinal Consumer Products (SAG-CS) has issued final opinions on o-Phenyl phenol (OPP; CAS No. 90-43-7) and Sodium o-Phenyl phenate (SOPP; CAS No. 132-27-4) in cosmetic products.

The assessments are particularly important because OPP has recently been classified as a Category 2 carcinogen under the GB Classification, Labelling and Packaging (GB CLP) Regulation. Despite this classification, SAG-CS concluded that OPP can be considered acceptable in specified cosmetic applications at controlled concentrations, based on the expected dermal exposure and the available toxicological evidence.

For SOPP, the opinion is even more significant from a regulatory perspective because the ingredient is not currently listed in Annex V of the UK Cosmetics Regulation and therefore is not presently permitted as a cosmetic preservative in Great Britain. The SAG-CS assessment provides scientific support for potential future regulatory authorization.

Why Are OPP and SOPP Important for Cosmetic Manufacturers?

OPP is an established preservative used in cosmetic products. Under the UK Cosmetics Regulation, it is currently listed in Annex V with maximum concentrations of:

• 0.2% in rinse-off products
• 0.15% in leave-on products

The regulatory attention surrounding OPP increased following its classification as a Category 2 carcinogenic substance under GB CLP. The classification triggered the need to consider whether continued cosmetic use could be justified under the relevant provisions of the UK Cosmetics Regulation.

SOPP is the sodium salt of OPP and has preservative functionality. However, unlike OPP, SOPP is not currently permitted as a preservative under the UK Cosmetics Regulation. OPSS therefore requested SAG-CS to evaluate its safety at proposed concentrations of 0.2% in rinse-off and 0.15% in leave-on products.

What Did the UK SAG-CS Conclude?

The SAG-CS reached broadly similar conclusions for OPP and SOPP regarding their safety under specified cosmetic conditions of use.

OPP – Key Conclusion

SAG-CS concluded that o-Phenyl phenol is acceptable for:

However, oral care products and products that lead to inhalation exposure, including spray products, were excluded from the assessment.

The SAG-CS considered the expected dermal exposure at these concentrations and concluded that OPP was unlikely to pose a genotoxic or carcinogenic risk under the proposed cosmetic conditions of use.

SOPP – Key Conclusion

For Sodium o-Phenyl phenate, SAG-CS similarly concluded that it is acceptable at:

Again, oral care and spray products are excluded from the safety assessment.

Importantly, this scientific conclusion does not itself authorize SOPP for use in cosmetics. SOPP would still require the appropriate regulatory action to become an authorized preservative under the UK Cosmetics Regulation.

OPP Category 2 Carcinogenicity: What Does It Mean?

One of the most important aspects of the OPP assessment is its classification as a Category 2 carcinogen under GB CLP.

The SAG-CS considered evidence indicating carcinogenic effects in experimental animals, particularly involving the urinary bladder following oral exposure. The group also considered evidence concerning genotoxicity and the proposed mode of action.

However, hazard classification does not automatically mean that every cosmetic use is prohibited.

The SAG-CS assessed the actual exposure associated with the proposed cosmetic use, rather than relying solely on the hazard classification. Considering the low expected dermal exposure at the proposed concentrations and the available mechanistic evidence, the group concluded that the carcinogenic risk under the assessed cosmetic conditions was unlikely to be significant.

This distinction between hazard classification and risk assessment is particularly important for cosmetic regulatory strategies involving CMR substances.

Safety Assessment: Margin of Safety

The SAG-CS safety assessment used conservative assumptions when evaluating dermal exposure.

For OPP, the assessment achieved an overall Margin of Safety (MoS) of 156 for aggregate dermal exposure at 0.2% in rinse-off and 0.15% in leave-on products.

For SOPP, an overall MoS of 139 was achieved under the same proposed concentration limits.

These findings supported the conclusion that the proposed dermal cosmetic uses could be considered acceptable, subject to the stated product-type limitations.

However, the assessments also identified areas where further evidence may be useful, particularly regarding exposure of children and adolescents.

Important Limitation: Children and Adolescents

A significant point for manufacturers is that no specific child-focused safety assessment has been submitted for either OPP or SOPP.

The SAG-CS therefore stated that a full risk assessment should be undertaken for children and adolescents when adequate data and an appropriate methodology become available.

This means manufacturers developing products specifically marketed toward children should not assume that the adult-based safety conclusion automatically addresses every potential exposure scenario.

A separate evaluation of:

• Intended age group
• Product type
• Frequency of use
• Exposure quantity
• Dermal exposure
• Potential incidental oral exposure

may therefore be necessary.

What About Using OPP and SOPP Together?

Another important compliance consideration is combined use.

The SAG-CS agreed with the approach previously established by the EU SCCS that when OPP and SOPP are used together, their combined concentration should not exceed:

• 0.15% in leave-on products
• 0.2% in rinse-off products

Therefore, manufacturers should not interpret the 0.15% and 0.2% limits as separate allowances that can simply be added together when both substances are present.

A formulation containing both ingredients requires careful assessment of the combined concentration.

Analytical Testing and Method Development

The SAG-CS opinions also highlight an important practical issue: analytical detection and quantification of OPP and SOPP in cosmetic matrices.

For OPP, existing analytical methods from other matrices may potentially be adapted for cosmetic products. However, suitable methods of development and validation would be required. Attention may be needed for extraction, phase partitioning and the relationship between OPP and SOPP during sample preparation.

For SOPP, the analytical situation can be more complex because SOPP may convert to OPP through proton exchange during sample preparation or analysis.

Consequently, laboratories and manufacturers should consider:

• Matrix-specific extraction procedures
• pH control
• OPP/SOPP equilibration
• Recovery studies
• Specificity
• Accuracy and precision
• Detection and quantification limits
• Stability during sample preparation
• Method validation

Analytical capability will become increasingly important if SOPP receives future authorization.

EU SCCS and UK SAG-CS: Regulatory Alignment

The UK assessment broadly aligns with the 2024 SCCS opinion on Biphenyl-2-ol and Sodium 2-biphenylolate.

The SCCS concluded that OPP and SOPP could be considered safe for dermally applied cosmetic products at:

• 0.2% in rinse-off products
• 0.15% in leave-on products

when used under the assessed conditions. The SCCS also stated that when both substances are used together, the combined concentration should remain within the applicable maximum concentration.

The UK SAG-CS assessment therefore provides an important example of scientific convergence between UK and EU cosmetic safety assessments, while the regulatory mechanisms themselves remain separate.

What Does This Mean for Cosmetic Manufacturers?

The SAG-CS opinions provide several practical compliance implications.

For OPP-Containing Products

Manufacturers should:

• Confirm current OPP concentration in every formulation.
• Verify whether products fall within rinse-off or leave-on categories.
• Confirm compliance with the applicable UK concentration limit.
• Identify spray and inhalation exposure scenarios.
• Review oral-care applications separately.
• Maintain supporting safety assessment documentation.
• Monitor future UK regulatory action following the SAG-CS opinion.

For SOPP-Containing Formulations

Because SOPP is not currently authorized as a preservative under the UK Cosmetics Regulation, manufacturers should not treat the SAG-CS opinion as an immediate authorization.

Instead, businesses should monitor potential regulatory amendments and assess whether future authorization could affect:

• Product formulations
• Preservative systems
• Product claims
• Ingredient specifications
• CPSR documentation
• Product Information Files (PIFs)
• Stability and microbiological testing strategies

UK OPP & SOPP Compliance Checklist – 2026

Key Takeaways for 2026

The UK SAG-CS opinions provide important scientific clarification for OPP and SOPP in cosmetic products.

For OPP:

• OPP remains a permitted UK cosmetic preservative.
• Maximum concentration remains 0.2% in rinse-off products.
• Maximum concentration remains 0.15% in leave-on products.
• Spray and oral-care products were excluded from the assessment.
• Category 2 carcinogenicity classification was specifically considered.

For SOPP:

• SOPP is currently not authorized as a cosmetic preservative in the UK.
• SAG-CS concluded that the substance is acceptable at 0.2% in rinse-off and 0.15% in leave-on products under the assessed conditions.
• Oral-care and spray products were excluded.
• The opinion may provide scientific support for potential future authorization.
• Combined OPP + SOPP use must remain within the applicable overall concentration limits.

The SAG-CS itself has no regulatory status; it provides scientific advice to OPSS, while decisions on legislative changes are ultimately made through the UK regulatory process.

FAQs

1. Is OPP currently allowed in UK cosmetics?

Yes. OPP is listed as a permitted preservative under Annex V of the UK Cosmetics Regulation, with a maximum concentration of 0.2% for rinse-off products and 0.15% for leave-on products.

2. Is SOPP currently allowed as a UK cosmetic preservative?

No. SOPP is not currently listed in Annex V of the UK Cosmetics Regulation as an authorized preservative.

3. Does the SAG-CS opinion automatically authorize SOPP?

No. SAG-CS provides scientific advice. Regulatory authorization would require the appropriate UK legislative process.

4. What are the maximum concentrations supported by SAG-CS?

The assessment supports 0.2% for rinse-off products and 0.15% for leave-on products, subject to the stated exclusions and conditions.

5. Can OPP and SOPP be used together?

They may be assessed together, but the combined concentration should not exceed 0.2% in rinse-off products or 0.15% in leave-on products.

6. Are spray products covered?

No. Products resulting in inhalation exposure, including spray products, were excluded from the SAG-CS safety assessment.

Conclusion

The 2026 UK SAG-CS opinions on o-Phenyl phenol and Sodium o-Phenyl phenate represent an important development for cosmetic ingredient compliance in Great Britain.

For OPP, the assessment provides scientific support for continued use at 0.2% in rinse-off and 0.15% in leave-on products, despite its Category 2 carcinogenicity classification, subject to the assessed conditions.

For SOPP, the opinion is particularly significant because the substance is currently not authorized as a UK cosmetic preservative. The SAG-CS conclusion could therefore support future regulatory consideration of SOPP, although authorization would still require formal regulatory action.

Manufacturers should now review formulations, concentration levels, product categories, analytical methods, safety documentation and future regulatory scenarios to ensure that their UK cosmetic portfolios remain prepared for potential changes.

How Maven Regulatory Solutions Can Help

Maven Regulatory Solutions supports cosmetic manufacturers, brand owners, ingredient suppliers and distributors with regulatory strategies for UK and international cosmetic markets.

Our services can support:

• UK Cosmetics Regulation Compliance
• Cosmetic ingredient regulatory assessments
• Preservative and CMR ingredient evaluations
• Cosmetic Product Safety Report (CPSR) support
• Product Information File (PIF) review
• Ingredient and formulation compliance assessment
• Safety assessment coordination
• Regulatory gap analysis
• UK/EU cosmetics regulatory monitoring
• Reformulation and compliance strategy
• Scientific and regulatory documentation

Stay ahead of UK cosmetic regulatory changes with Maven Regulatory Solutions.