Every outdoor adventurer is familiar with ticks. Some may think of the sneaky, blood-sucking parasites only as annoying pests; however, ticks actually pose a significant threat to human health.1 Many compounds have been tested for their ability to ward off ticks and other insects. Recently, essential oils have been studied intensely for their promising repellent potential.
One study by European researchers at the Slovak Academy of Sciences investigated the repellent effects of several essential oils against Dermacentor reticulatus, a species commonly known as the ornate dog tick. The essential oils in question included clove, citronella, creeping thyme*, peppermint, spearmint, and red thyme.* A blend of thyme* and citronella was also tested.
The researchers began by collecting wild ticks and then testing them for responsiveness to human breath. Some ticks responded by walking vigorously toward the source, while others did not show any measurable response. Only the responsive ticks were included in the study.
The researchers built a tiny arena for the ticks using a small plastic container. The upper half of the arena’s walls were lined with filter paper, which had been sprayed beforehand with an ethanol solution containing different essential oils. Ten minutes after applying the essential oil/ethanol mixture, 30 ticks were placed in the bottom of the container, and their behavior was observed for two hours. Each tick that climbed up onto the treated area with its entire body (without immediately jumping off) was removed from the arena and categorized as “not repelled.” The experiment was repeated many times; more than 1,300 ticks were tested.
In the control group (containing arena walls treated with ethanol solution only), more than 95 percent of ticks were reliably categorized as “not repelled” in almost every trial, equating to a repellency rate of less than 5 percent. The contrast in results from the treatment groups was amazing. The red thyme, creeping thyme, and clove essential oil groups showed the highest repellency, at 68, 82, and 83 percent respectively. The mixture of citronella and creeping thyme was the most effective, at 91 percent repellency, which is significantly more effective than either citronella or thyme alone. Even more astounding is the fact that the concentration of the essential oils was only 3 percent of the solution in each trial.
The results from this study are quite significant. They strongly support a growing body of evidence indicating that some essential oils are powerful agents for protecting against ticks and other insect parasites. This study also showed that essential oils in a blend can have synergistic effects. Although further research is needed to understand how this works, this helps explain why essential oils are often used in natural bug repellent blends.
*Note that the thyme species tested in this experiment were not the same species as doTERRA Thyme, although their essential oils do have similar chemical composition, being predominantly composed of the constituent thymol.