Have You Heard . . .
That lavender and tea tree oil can cause little boys to grow breasts? Though I’ve definitely pulled out the lavender for my kids on many occasions and I use tea tree oil in my diaper wipe solution, there have been times when I’ve held back over concerns about possible estrogenic effects, both for them and myself.
Turns out, there was probably nothing to worry about.
Thanks to a tip from Paula on a Facebook post last week, I dug up the often cited 2007 study which first claimed lavender and tea tree oil are hormone disruptors. Not only was it poorly constructed and vague, it has a sample pool of only three people!!
The boys (ages four, seven and ten), apparently used **some kind of product** which contained these oils. The products weren’t analyzed for the presence of other potential hormone disruptors, and the oils weren’t checked for purity. After developing their hypothesis, the researchers decided to test lavender and tea tree oil with human cells in a petri dish. Though the results did show estrogenic activity, that’s probably because the solvent they used to dilute the oils – dimethyl sulfoxide – is a known estrogen mimicker! Furthermore:
“If you take a close look at the study, some issues are raised . . . The full list of ingredients in these products were not mentioned, nor the possible chemicals included in the packaging of the products. Parabens were likely included in the ingredients and phthalates in the packaging. In a recent study, diethyl phthalate was found in 103 out of 252 products, which included fragrances, hair care products, deodorants, nail polishes, lotions, skin cleansers and baby products.3 Both phthalates and parabens have been shown to have an estrogenicity presence.4&5“
Clearly, the results of this study are desperately lacking in meaningful analysis. So what do we know, really?
What Studies REALLY Say About Lavender & Tea Tree
According to three doctors representing Wake Forest, Yale and Harvard respectively, “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.” (Source)
Even more helpful is this study, which measured “the effect of a test substance on the uterus of immature or estrogen-deprived female rats over three days. Any estrogenic action causes a rapid and measurable increase in uterine weight. The assay has been in use since the 1930s, was adopted by the OECD in 2007, and is now regarded as the ‘benchmark animal assay for estrogenic effects.'” (Source: World renowned essential oil expert Robert Tisserand)
The results? Even in concentrations 6,000 and 30,000 times greater than estimated exposure from multiple cosmetic products containing lavender oil, there was absolutely no effect on the uterus of the rats.
Zip. Nada. Nothing.
As far as I can tell, the 2007 study is the only one which implicates lavender and tea tree as estrogenic. Given how poorly constructed it was and the fact that the only “gold standard” study we have says lavender is not estrogenic, I am not inclined to trust the results on tea tree oil either. Thank you Paula for putting my mind at ease!