News Room

CTFA Statement on Essential Oils

February 1, 2007

Contact:  Lisa Powers, CTFA (202) 331-1770

Response to Study on Reported Hormonal Effects of Lavender and Tea Tree Oils

In what it called a “brief report,” the New England Journal of Medicine (NEJM) today linked prepubertal gynecomastia [breast enlargement] in young boys to the use of products with lavender or tea tree oils.  Correlating essential oils exposure to gynecomastia was first reported at the Endocrine Society meeting in June 2006.   At that time, investigators reported that it was too soon to draw any firm conclusions from the observations of five boys found using topical products that listed lavender or tea tree oils among their ingredients. They concluded that “an epidemiological study would be appropriate to determine whether genetic or environmental factors might also contribute to the observed effect.”

The earlier report has now been published in the NEJM describing gynecomastia in three subjects as opposed to the five presented in the earlier report.  Authors of the NEJM’s report describe prepubertal gynecomastia as “extremely uncommon.” 

It is important to note that this report does not present any information about the content of these essential oils in the products referenced; therefore it is not possible to determine accurately any measure of exposure (area and frequency of application) or if there is a correlation between content and effect. One of the patients reportedly used lavender and tea tree oil-containing styling gel and shampoo; neither product type would result in significant exposure. Another used both soap and lotion, but the lotion use was described as intermittent, and exposure from soap would be minimal since it is a rinse-off product.  None of these exposures are consistent with a cause and effect relationship. 

The NEJM described in vitro results indicating that these essential oils have estrogenic and anti-androgenic effects.  However, these are not rigorous tests that are adequate to establish or confirm an estrogenic and/or anti-androgenic effect.  In fact, the authors themselves describe the estrogenic and anti-androgenic effects obtained in these in vitro studies as “weak”.  This means that the evidence is not sufficient to establish exposure to tea tree oil and lavender oil in prepubertal gynecomastia, which is a highly uncommon condition. 

The cosmetic industry, in conjunction with the fragrance industry, will continue to follow the medical literature to determine whether this is more than just a clinical oddity in a very limited sample.