The European Commission’s Scientific Committee on Consumer Products (SCCP) issued its opinion on tea tree oil, finding the substance can sensitize skin and induce skin and eye irritation. In regard to the material’s safety, however, the group could not form an opinion due to lack of data.
The SCCP Opinion released on Dec. 16, 2008, states that, when exposed to air and heat, tea tree oil is prone to oxidation and yields epoxides and other oxidation products that contribute to its skin sensitizing potential. The SCCP added that it is important to consider that certain formulations tend to reduce tea tree oil’s stability. According to the Code of Practice and the Guidance document introduced by the Australian Tea Tree Oil Association, safe processing and storage may be achieved and controlled by the p-cymene content of a given formulation.
Neat tea tree oil and certain formulations at concentrations of 5% or more were found to induce skin and eye irritation. Clinical data also showed that current use levels of tea tree oil could induce contact allergy and that percutaneous absorption of some constituents could occur, leading to a considerable systemic exposure, especially from neat oil, body lotion and foot spray/powder. However, inadequate dermal absorption studies were available and thus the magnitude of systemic exposure to tea tree oil from cosmetic products remains uncertain.
Should reliable data on percutaneous absorption covering relevant concentrations and cosmetic formulations be provided, the SCCP anticipates a reassessment of the safety of tea tree oil.