Pure Wellness Centers

A February 2007 article in the New England Journal of Medicine received a lot of attention in the popular press as it concluded that lavender and tea tree oils may have feminizing effects. Three cases of growth of breast tissue were reported in young boys using lavender or tea tree oil products. Later lab studies showed female hormone-stimulating effects on cancer cells. The EU’s Scientific Committee on Consumer Products may decide to ban the oils, as they can be irritating to the skin.

While this study reports important case studies, it does not conclusively say that tea tree leads to growth of breasts in young boys. Many mainstream articles on this study refer only to tea tree oil, but only one of the three boys was using tea tree. There are no other such reports among the millions of users of tea tree oil or lavender. The researchers used breast cancer cell lines to test the straight oil and found estrogenic (female hormone) and anti-androgenic (male hormone) effects. This study warrants repeat, and should perhaps be performed on healthy cell lines. A study has also found that a component from tea tree inhibits skin cancer cells. This study holds no more or less weight than the one currently in question. The boys are exposed to hormones in meats and dairy products as well as estrogen-like compounds in plastics and this may be a consideration. It is important to note that while the symptoms did resolve after discontinuing the products, months passed before symptoms fully resolved. Blood hormone levels were not affected.

Herbs and their oils can cause allergic and skin reactions. Essential oils can be toxic in high doses. I do not think that these facts alone warrant a banning of the oils or the products. We use toxic products daily- with caution and advice. Tea tree is antimicrobial. Like almost all of our antibiotics, it can lead to bacterial resistance when used repeatedly. This is not a reason to stop using antibiotics altogether.

As always, I caution against ever drawing a conclusion based on one study. In order to form a conclusion, one should look at all the research done thus far (or at reviews of the literature) and take into account areas which call for further study.

Guardian UK article
The original New England Journal of Medicine article

A reprint from the British Medical Journal, different abstract

Candace McNaughton, ND