According to the institute, the assessment showed that the substance can be metabolized in the skin to D-glucose and hydroquinone, a suspected carcinogen which is banned from use in cosmetic products in Europe.
The institute further explains that their assessments showed that by metabolic processes in the skin, the substance in D-glucose and hydroquinone are split, thus hydroquinone is suspected to be carcinogenic.
Although β-arbutin used as a skin whitening agent in cosmetics is prohibited in cosmetics in Europe, from the BfR's point of view; "the substance should still be seen critically due to its property of releasing hydroquinone."
Currently, the European Commission’s Scientific Committee for Consumer Safety (SCCS) are said to be re-assessing the safety of the compound for use as an active substance.
'Following EC opinion'
The last review of the substance in Europe was back in 2008 when the Scientific Committee on Consumer Products (SCCP) concluded that where hydroquinone was initially permitted at a concentration of 2 per cent, it recommended that the substance should not be used any more as a depigmentating agent in cosmetic products due to observed clinical side effects, among which, exogenous ochronisis.
Then it stated; "Consequently, we consider the currently requested use of β-arbutin in cosmetic products unsafe. In addition, it is also our opinion that the same concern can be expressed for other products that result in the release and/or formation of hydroquinone before or upon application on the skin."
Today, the BfR says it still following that opinion and that in order to assess whether the health risks of using β-arbutin meet the health risks of hydroquinone, data speed of the enzymatic metabolism of β-arbutin in the skin needs to be clarified.
"Although the general toxicological assessment of β-arbutin suggests that the substance may be safe, the bioavailability of hydroquinone under conditions of intended use of the substance is of concern."