Joe Maller.com

Are Lavender and Tea Tree Oils estrogenic?

There’s a bit of a monster pesticide-resistant lice epidemic going around New York City, it seems like every school near us is infested. Last week, a third of my younger daughter’s class had lice. We didn’t.

Besides regular comb outs and wearing their hair up or in braids, we’ve been applying aromatic oils to our daughters’ heads before school. The mix of oils was recommended by a friend:

  • Tea tree, lemongrass & lavender in apricot kernel oil (25% dilution)
  • Put a couple of drops on your hands, rub palms together & then pat it on the hair.
  • Avoid contact with skin
  • Definitely avoid contact with eyes!

I mentioned the oils to some other parents and emailed it to the class. This morning the classroom smelled like tea tree oil.

But one parent mentioned some concern about estrogenic qualities of lavender and tea tree oils. This was troubling me so I did some research. Check out the most thorough essential oils guide

From what I found, the concern about tea tree and lavender originated with this 2007 observational study published in The New England Journal of Medicine (NEJM):

Prepubertal Gynecomastia Linked to Lavender and Tea Tree Oils

NEJM received several critical letters about the study which should be read too.

This was foremost an observational study, and the author’s conclusions seem loosely drawn from the results of three cases. (Gynecomastia is enlarged breasts in males) From their abstract:

We investigated possible causes of gynecomastia in three prepubertal boys who were otherwise healthy and had normal serum concentrations of endogenous steroids. In all three boys, gynecomastia coincided with the topical application of products that contained lavender and tea tree oils. Gynecomastia resolved in each patient shortly after the use of products containing these oils was discontinued.

First issue with the study is that not all three cases were exposed to tea tree and lavender, here’s what they mention in the text:

  • patient 1: “healing balm” containing lavender oil
  • patient 2: regular use of styling gel and shampoo containing tea tree and lavender oils
  • patient 3: lavender scented soap and occasional lavender lotions

Only one of the three of their observed subjects even recorded contact with tea tree oil.

As pointed out in the letters, there’s virtually no mention of dietary factors. Soy is known to have estrogenic effects and processed soy products are in everything these days.

Experiments using breast cancer cells to measure estrogenic effects seem to only vaguely apply to gene-expression in boys.

Both oils stimulate ERE-dependent luciferase activity in a dose-dependent manner, with the maximum activity observed at 0.025% volume per volume (vol/vol) for each oil, corresponding to approximately 50% of the activity elicited by 1 nM 17β-estradiol. Treatment with higher doses of the oils was cytotoxic.

The most extreme numbers were collected at the maximum possible oil dose before the cells they were treating were poisoned so much they died. I have no idea what that dosing would be to a human, but I suspect there’d be significant physical reaction before getting to that point.

Presenting their findings as “Average fold increase above control” without the actual numbers can be suspect. An increase from 0.02 to 0.06 is a three-fold increase, but still relatively insignificant.

Also, the delivery vehicle used in testing, dimethylsulfoxide, is suspected of having estrogenic effects:

Our data show that DMSO-induced significant increase in ERα, ERβ, Vtg and Zr-protein genes in a time-dependent manner. Indirect ELISA analysis showed a time-specific effect of DMSO. The use of DMSO as carrier solvent in fish endocrine disruption studies should be re-evaluated.

Most tea tree oil studies in PubMed seem to be related to its anti-fungal qualities or efficacy as a delivery vehicle for topical medications. I did find one study which looked at transdermal absorption of tea tree oil and found that very little passes through the skin:

…only a small quantity of TTO components, 1.1–1.9% and 2–4% of the applied amount following application of a 20% TTO solution and pure TTO, respectively, penetrated into or through human epidermis.

I believe this study looking at the effects of dietary soy proteins on tumor growth demonstrates greater estrogenic effects of dietary soy protein isolate than the tea tree oil study showed with direct in vitro exposure.


  • Laidir

    Firstly, in the study done, the researchers used “pure” lavender and tea tree oil… and the study indeed proved that “pure” lavender and tea tree oil were mimicking estrogens in cells. This was also proven when all thre bosy stopped using the particular products concerned… their condition reversed itself.

    Secondly Irregardless as to what the other ingredients are in any products they used, it is commonly known that MANy essential oils and herbs are phytoestrogenic, and can mimic weak estrogens in the body. These guys only tested TWo pure oils…the field is wide open for more oils to be tested.

    There is no doubt whatsoever that all the chemicals you refer to are xenoestrogens…but thats nothing new. I think what we DID need to know is that even essential oils can cause allergies, or be harmful in respoect to hormone imbalance. Xenoestrogen? Phytoestrogen? E2 estrogen? E16 estrogen… whatever type they are they ALL contribute to estrogen dominance in the4 end and can cause problems not just in post menopausal women, or pre menopausal women but anyone.

    There was absolutely nothing biased about the study either… they went straight to the pure oil versions of the product. Now THAt I find distrurbing…because if those thre bosy gynomastia reversed just stopping the use of what are effectively very weak and watereddown samples of both oils, what on earth is the pure oil going to cause in people when they dabble with the different strengths and concoct their own mixes from esstial oil suppliers?

    ANY amount of estrogen dominance is not good for people who are prone to cancers that are dependant upon estrogen to thrive and to grow. That is most types of cancer. There is some pathetic study out there were the body shop dionated “lotions” to do sopme study… quite obviously some watered down mix of the stuff… obviously using these products over time builds up estrogens in the body that are not easily detoxed without complete withdrawal from use of the product.

    They never looked at diet, because they got PRECISELY the results they needed just studying the oils… though there are some other causes for such estrogens, had they not managed to reverse the gynomastia with removal of the products with oils… I’m sure they may have gone on to check OTHER ingredients (common) in the product itself – it still does NOT discount their research or make it any less accurate does it?

    We would do much better if we did not have people who went into denial where it comes to scientific study and I think it is HIGH time they DID do study into the countless so called “natural” remedies we use actually…just because something is “natural” doesn’t make it safe for :”everyone” to use. Belladonna (weed) is natural but deadly… and I think we deserve to know the truth… if this stuff has so called been used for thousands of years..it is only the last few decades that we have started to study this stuff… and goon on them for doing so!

    We all need to know the truth about anything “natural” as well as the countless harmful drugs we are palmed off with… no bias. I don’t want tome “natrual health freak” preventing my children from mlearning about what is good for their body because the natural health freak has a financial interest in so called oils and sells them for a living. Nice to look at, nice to smell… rub it on and boys boobs swell. Lets see some non biased studies to prove it wrong… preferably ones that don’t involve some “brand” of lotion for the testing just to convince their customers their shit is kosher.

    • Jennifer

      You lost me at “irregardless.” No seriously, I stopped reading and discounted everything else you wrote.

      • Deborah Fenker

        HA hahahaha me too. :D

    • Just2016stuff

      In natural toothpastes, you can find tea tree oil, peppermint oil, mint oil, etc..all of which are phytoestrogenic. When it comes to toothpastes, Miessense is the only brand to carry pure and good for the body stuff. Many female “natural stuff” freaks make things that are good for some people but not all. Women can absorb a higher ceiling of estrogen and not have a lasting effect whereas if men absorb them in small amounts, anything from fatigue to gynecomastia can happen. Women can live through it for some time and be free of it without much damage to their body. But for men, it won’t be noticeable at first or the following few weeks or so but it will catch up to a point where it takes over and blocks testosterone. It’s all put in place by the establishment and banks to emasculate men. There are numerous methods and even natural methods for body revamp and remedies that won’t be adopted to the mainstream. Stop use immediately if signs of gynecomastia is noticed. Heck, the very word ‘gynecomastia’, and ‘phytoestrogen’ aren’t even in the online typing dictionary. People who already had surgeries for gynecomastia has to take a step back, observe, read, and try to remember almost all the causes and then work towards avoiding those elements and finding new way of lifestyle.
      Cancer prone people should worry about their endocrine more than they do for other stuff. Many glands are responsible for making our body work the way it does so anything from thyroid to pineal gland to sweat glands are to be paid attention for. EWG has many records but they only look for natural stuff and doesn’t care for phytoestrogens. Don’t trust doctors immediately but definitely have some clue about the thing you want them to help fix and watch your time with their treatment. If it’s causing side effects like weight gain, water retention, poor quality of life, bounce back and rethink, pray to God. Submit your all and all to Jesus because that’s the only foolproof method I know.

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