SCCS Issued Final Opinion on Thiomersal and Phenylmercuric Salts as Peservatives in Cosmetic Products

On 10 February 2026, the Scientific Committee on Consumer Safety (SCCS) of the European Union issued final opinion (SCCS/1686/25) on the safety of Thiomersal (CAS No 54-64-8) and Phenylmercuric salts (CAS No 62-38-4, 94-43-9) as preservatives in cosmetic products.

Final Opinion on Thiomersal and Phenylmercuric Salts

Considering that the Margin of Safety based on renal toxicity as the most sensitive endpoint is less than 100, and that genotoxicity evidence is unresolved, the use of ‘Thiomersal’ and ‘Phenylmercuric salts’ as preservatives in cosmetic eye products is not considered safe at the concentration levels currently permitted in cosmetic products.

The potential risk for human health from use in cosmetic eye products is aggravated by additional exposure to mercuric compounds from sources other than cosmetics.

Interpretation of Thiomersal and Phenylmercuric Salts

The Global Cosmetic Ingredient Regulatory Database-Global CosIng, independently developed by CIRS Group indicates that in EU, Thiomersal and Phenylmercuric Salts have been included in the List of preservatives allowed in cosmetic products. Detailed information could be found in the following figures.

In China, Thiomersal and Phenylmercuric Salts have been included in Inventory of Existing Cosmetic Ingredients in China (IECIC) (I) and List of preservatives allowed in cosmetic products. Detailed information could be found in the following figures.

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Further Information

SCCS-Thiomersal and Phenylmercuric Salts