Even though the story has been all over the news and the Internet, there is actually only ONE study that makes these claims and now spreads the panic. The sources of mass information loves to shock us. So, we took a closer look at the study.
Originally published in the New England Journal of Medicine, the study details three young boys who had developed gynecomastia (breasts). The doctors treating the boys learned that each of them were using products with lavender or tea tree essential oils, and once they stopped using these products, the breasts went away. The researchers then took these case studies and decided to test the essential oils on human tissue in a lab. According to their study, the essential oils acted estrogenically, and thus could have been the cause of the breast development in the boys.
However, we, along with numerous researchers and doctors have found some major flaws in the study.
Before we get in to more specifics--just a quick note. Looking at the footnotes of the study, you'll notice that all of the doctors who conducted the research are sponsored by numerous drug companies. Hmm, no wonder...
Three doctors (Kathi J. Kemper, M.D., M.P.H., Wake Forest University School of Medicine, Winston-Salem, NC 27157; Aviva J. Romm, Yale University School of Medicine, New Haven, CT 06510; Paula Gardiner, M.D., M.P.H., Harvard Medical School, Boston, MA 02215) wrote a commentary on the study:
"The study by Henley et al. (Feb. 1 issue)1 raises many questions. Product names were not provided. Did the authors contact manufacturers to report concerns or ask about constituents? The variability, adulteration, and contamination of herbal products have been widely reported,2,3 as have discrepancies between labels and contents.4 Plastic containers may contain phthalates, known endocrine disrupters.5 What was actually in the products cited in this report?The researchers said that it is possible that the boys' breast growth may have stemmed from other causes. The doctors bring up a few great points here, with the main one, whether any other estrogen mimickers were present in these products used on the young boys? Parabens? Phalates? The ingredients are not documented, and it could be a number of things--even from using bottles made with BPA or consuming genetically altered fast food?
None of the hormonal testing showed abnormal results, except in Patient 2, who had elevated levels of testosterone (not estrogen). There was no report on ultrasound examination or needle biopsy, nor were subsequent weight changes reported. Might the patients' gynecomastia have reflected another pathophysiological process that resolved spontaneously?Traditional use and clinical trials have not suggested estrogenic effects of tea tree or lavender oil, though estrogenic effects have been reported for other essential oils and plants. Are occupational exposures to lavender and tea tree associated with estrogenic symptoms? In vitro testing alone is not adequate grounds for indicting traditionally used products and may raise public fear."
But what about the laboratory tests they did on petri dishes of human cells? If you look carefully at their study, you'll notice they didn't apply pure lavender or tea tree essential oil on the cells they were testing, they used a solvent to dilute the oils. The solvent is dimethyl sulfoxide---which, as it turns out, is an estrogen mimicker! (as documented here.) And rates 6 on Skin Deep.
The bottom line is that lavender and tea tree essential oils have been used for thousands of years with no history or evidence of estrogen mimicry. They're probably the most widely used essential oils in baby products due to it's safety and remarkable qualities, so indeed the three boys in the study were using them, along with millions of other babies. If lavender and tea tree essential oils were truly estrogen mimickers, we would have known about their effects long time ago. Lavender and tea tree are listed by a large number of aromatherapy sources as being oils that can be used undiluted. Undiluted use of lavender and tea tree, however, should only be done on rare occurrences as some sensitivity still could occur in some overly sensitive individuals. But as safe as they are, again, the rule of thumb is to never use any essential oil undiluted.