Low risk of skin sensitisation. Safety Cautions (Dermal): Avoid using aged or oxidised oils.
Maximum dermal use level: 15%. Safety Recommendations: For clinical or personal care use, an effective and safe concentration of unoxidised tea tree oil typically falls within the 10–20% range. Therefore, we propose a maximum limit of 15%. Prevent oxidation of tea tree oil by storing it in a dark, airtight container within a refrigerator. It is also advisable to include an antioxidant in products containing this oil.
Avoid using undiluted tea tree oil on the skin due to the risk of sensitisation.
Regulatory Guidelines: In Germany, the Federal Institute for Risk Assessment (BfR) recommends limiting the concentration of tea tree oil in cosmetic products to a maximum of 1%. COLIPA (now known as Cosmetics Europe) has made similar recommendations, suggesting the use of antioxidants in products containing tea tree oil and/or specific packaging to minimise exposure to light. In Australia, tea tree oil is classified as a 'Schedule 6' poison, indicating a moderate potential for causing harm. Specific packaging with strong warnings and safety directions on the label is required. Warnings typically include keeping the product out of reach of children and not ingesting it. While child-resistant closures are recommended for tea tree oil and other essential oils, they are not consistently used outside of Australia.
Although tea tree oil is not restricted in cosmetics in the EU, it is no longer allowed as an ingredient in products making insect repellent claims, not due to safety concerns but because no manufacturer registered tea tree oil as an insect repellent within the deadline set by the European Biocide Products Directive. This registration process was made onerous for natural product manufacturers by the European chemicals industry.