Lavender and tea tree oils may cause breast growth in boys

Repeated topical
use of products containing lavender oil and/or tea tree
oil may result in enlarged breast tissue in prepubescent
boys, a rare condition known as prepubertal
gynecomastia, reports a study in The New England Journal
of Medicine.

Clifford Block,
MD, in Colorado suspected the lavender and tea tree oils
after diagnosing three young male patients with prepubertal
gynecomastia. The three Caucasian boys, ages 4, 7, and
10 years, were otherwise healthy and had normal
hormonal levels when they were diagnosed with
gynecomastia. All had either used lavender-scented soap and
skin lotions, or shampoos and styling products
containing tea tree oil and lavender oil. Several
months after they stopped using the products, the
gynecomastia had lessened or reversed.

In the current
laboratory study, researchers at the National Institute of
Environmental Health Sciences sought to verify whether the
oils effected abnormal hormonal changes in the boys.

"The results of
our laboratory studies confirm that pure lavender and
tea tree oils can mimic the actions of estrogens and inhibit
the effects of androgens," said Ken Korach, of the
Laboratory Reproductive and Developmental Toxicology
at NIEHS and author of the study in a release. "This
combinatorial activity makes them somewhat unique as
endocrine disruptors."

Researchers
caution that the findings are only applicable to young males
with unexplainable enlarged breasts who are regularly using
products containing these essential oils. Further
research is needed to determine if the oils have
similar endocrine-disrupting effects in prepubertal
girls, adolescents, or adults. (The Advocate)