Robert Tisserand on Lavender and Tea Tree reported as hormone disruptors

Please watch the video for Robert's comments at the moment. Below is a summary of his stance, with links to previous articles and research papers at the bottom.

New research does not confirm estrogenic effects for essential oils

Research that has not yet been published, but which was the subject of a recent press release, appears to add little new or convincing evidence that essential oils present any risk of hormone-disruption.

The study is said to demonstrate that, of eight essential oil constituents studied, all of them showed a hormonal effect in vitro, either estrogenic or anti-androgenic. The constituents were selected because they occur in lavender and/or tea tree oils, which were the subject of previous research by Korach.

* This was an in vitro study, and as such does not tell us whether such an effect takes place in the human body, or what the threshold dose would be.

* The full research has not yet been published, so we don't know how potent the effects were. Very weak estrogenic activity, 10,000 times weaker than human estrogen, is typical of estrogens from plant sources.

* Research using a standard protocol in pregnant rats has shown that topically applied lavender oil is not estrogenic.

* In cases where lavender oil is thought to have caused breast growth in pre-pubertal children, none of them showed elevated levels of estrogen.

It is feasible that the hormonal effects seen from in vitro testing is caused by phthalates leached out of plastics used in the testing.

* One of the authors co-published a 2007 study showing an in vitro estrogenic effect for lavender oil and tea tree oil.

* In the 2007 study, 96-well trays were used. These are made of plastic that contains estrogenic substances such as phthalates.

* We know from other research that essential oils leach these substances out of plastic.

* This creates doubt about whether the essential oils were responsible for the in vitro effects.

* If the phthalates etc. are responsible for the hormonal effects noted, this would explain why all 8 constituents seemed to be active, probably with different potencies related to the degree of leaching.

Older posts on the topic:

http://roberttisserand.com/201....3/02/lavender-oil-is
http://roberttisserand.com/201....4/02/estrogens-in-pl

Carson, C. F., Tisserand, R., & Larkman, T. (2014). Lack of evidence that essential oils affect puberty. Reproductive Toxicology, 44, 50–51. http://doi.org/1…/j.reprotox.2013.09.010