The Australian “Tea Tree” received its name from the famous Captain Cook, who found its aromatic, resinous leaves a tolerable substitute for tea. Later, the oil of the tea tree leaf was found to possess strong antibacterial and antifungal properties. Over time, so many claimed benefits have become attached to tea tree oil that it is often marketed as something of a panacea. Few of these potential uses, however, have undergone any meaningful scientific study.
Acne is one condition for which use of tea tree oil certainly makes logical sense. A variety of topical antibiotics and antiseptics have been proven effective for acne; since tea tree oil has unquestioned antiseptic properties, one might reasonably hypothesize that it too would work for acne.
But a hypothesis is one thing; proof is another. To properly determine whether a medical treatment is effective, researchers must test it in a double-blind, placebo-controlled study. Up until recently, however, no such study of tea tree oil had been reported.
In early 2007, Indian researchers published the results of the first randomized double-blind clinical trial testing the effectiveness of tea tree oil for acne. This study enrolled 60 people with mild to moderate acne. Participants were divided into two groups and treated either with placebo or with 5% tea tree oil gel. Over the 45-day study period, researchers evaluated acne severity in two ways: they counted the total number of acne lesions (TLC) and rated acne severity on a standardized index (ASI).
When the results were tabulated, the researchers found that tea tree oil gel was significantly more effective than placebo on both counts. Tea tree oil reduced the number of acne lesions and also their severity, producing a benefit that the researchers considered meaningful in real life terms.
However, while this is promising, one study is never enough; several more studies performed by independent research groups will be necessary to truly establish tea tree oil as an effective treatment for acne.
For more information, including important safety issues, see the full tea tree oil article.