Australian Lemon Myrtle contains the highest natural concentrations of citral of any plant source - the GC results for our Lemon Myrtle Oil typically demonstrate a 93% citral level.
Citral itself has been generally recognized as safe with the FEMA GRAS listing. When incorporated into the formula of up to 1%, Lemon Myrtle Oil is considered safe with minimal skin irritation.
The International Fragrance Association (IFRA) recommends that citral be used in association with substances that prevent a sensitizing effect. While a different high citral oil, Lemon Verbena oil (Lippa citriodora, Kunth), has been banned for use in cosmetics by the European Commission since Dec 2009, Lemon Myrtle Oil is well tolerated with no such restrictions.
An in vitro study to determine the absorption and histopathology response of Lemon Myrtle Oil on full-thickness freshly excised human skin was conducted. A formulated product containing 1% Lemon Myrtle Oil at 8 hours of exposure showed limited damage to epidermal cells, as observed from histopathological assessment of exposed skin. The authors concluded that the low toxicity of 1% Lemon Myrtle Oil makes it suitable for use in topical antimicrobial products.
In the same study, researchers also determined that blending Tea Tree Oil with Lemon Myrtle Mil at 1:4 ratio would improve the potential microbiological activity of the Tea Tree Oil and concurrently reduce the sensitizing effects of Lemon Myrtle Oil.
In vitro cytotoxicity testing conducted during this study revealed both Lemon Myrtle Oil and citral may have a toxic effect on human cell lines when concentrations exceed 1%. However, at concentrations up to 1% Lemon Myrtle was significantly less toxic to human skin cells and skin fibroblasts.
The pH range of Lemon Myrtle Oil is about 5.5 - 8.0. Toxicity is stated as a LD50 of 2.25 mg/kg for rabbits, as reported in a 1974 study. The oral LD50 value for rats was reported at 4.96 mg/kg in a 1964 study.