Do lavender & tea tree essential oils cause breast growth in boys? Are they endocrine disruptors?

Lavender flower bunchAt the BlogHer’08 conference, one of the topics among green bloggers was whether it was safe to steer people to products containing lavender and tea tree essential oils.  If you are trying to steer clear of phthalates in fragrance and parabens as a preservative, you might switch to natural products containing lavender and tea tree essential oils.  And many baby personal care products contain lavender especially since it is believed to be calming.  Tea tree essential oil makes a great disinfectant spray – and can be used to clean mold.

But, you may recall that last year, an article in the New England Journal of Medicine reported that the use of certain products containing lavender and tea tree oils was associated with the breast tissue growth in boys prior to puberty.  This has led to some concern that lavender and tea tree essential oils may be endocrine disruptors, and should be avoided.

So, after the conference, I went back and looked at the research.  The report was 3 case studies – 3 boys, ages 4, 7 and 10.  The case studies all involved the topical application of products containing lavender and tea tree essential oils, and the 3 boys experienced breast tissued growth.  The enlarged breast tissue subsided once the products were discontinued.  So, it was believed that the breast tissue growth was associated with the products.  Breast tissue growth is generally attributed to interference with the hormone signaling – the endocrine system.  Subsequent laboratory studies showed weak but definite endocrine disrupting effects for lavender and tea tree oils. 

But, were the products really the cause, and did they contain lavender and tea tree essential oils?  I think that is a little unclear.  The case report does not provide detail as to whether the products at issue actually contained tea tree or lavender essential oil.  The first boy is reported using a healing balm contaning lavender oil, but there is no analysis or detail on the actual ingredient.  The second, styling gel and shampoo listing lavender oil and tea tree oil.  The third, lavender scented soap and skin lotions, but no confirmation that the lavender was synthetic as opposed to natural.    

More importantly, the case report does not seem to evaluate the boys’ exposure to any other known endocrine disrupting chemicals – PCBs, organochlorine pesticides, phthalates, parabens, or alkyl phenols.  And phthalates and parabens are commonly found in personal care products. 

As for the laboratory studies? Not unexpected.  In vitro studies have previously identified weak hormonal effects from essential oils – but these are very weak. 

My conclusion?  I think it is clear that there is not enough information.  I think using tea tree essential oil for cleaning is not a problem.  (Smart Mama Simple Tip:  A great disinfectant – 2 teaspoons tea tree essential oil in 2 cups water in a spray bottle.)  But, you may want to consider avoiding repeated skin application of personal care products intended to be left on (such as moisturizing lotions) containing lavender and tea tree essential oils.

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  1. I use essential oils when doing aromatherapy. Essential oils are very soothing.

  2. the good thing about essential oils is that they are therapeutic and smells great

  3. My daughter developed breast tissue development at 2 1/2 and we were told that it was phytoestogens, and told by the doctors (at a medical college) to stop exposing her to soy, lavender, and Tea tree oil. We used them sparingly, but we did use them. I also removed all the plastic from the house as well as stopped drinking tap water, eat grass fed beef w/o hormones etc., and we changed our grooming products. The symptoms regressed after 6 mos. You can say that it could have been any of these things, but I still think steering clear of all of them, until a child has reached puberty is best. Smelling them isn’t the problem, getting them on your skin is.


  1. […] So the second reason, and the more important reason, is because lavender and tea tree oils are presented conclusively as posing a “hormone disruption dilemma.” Dr. Epstein writes that they cause breast enlargement in young boys. Which is why I was even looking at the citation to see if there was some new medical study other than one from several years ago, which I talked about in a blog in 2008. […]

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