Essential Oils

Lavender and tea tree oil have grown in popularity as “alternative medicines” for various ailments, but their use may have an adverse effect on young boys.

A new study from the National Institute of Environmental Health Sciences found that key chemicals in lavender and tea tree oil could lead to male prepubertal gynecomastia on prepubescent boys. To put it simply, it can lead to moobs.

“Our society deems essential oils as safe,” said J. Tyler Ramsey, B.S., a post-baccalaureate research fellow at the NIH National Institute of Environmental Health Sciences, during a talk at the Endocrine Society’s ENDO 2018 event yesterday. “However, they possess a diverse amount of chemicals and should be used with caution because some of these chemicals are potential endocrine disruptors.”

This is not the first study to link lavender and tea tree oils to male prepubertal gynecomastia. A study from 2007 in the New England Journal of Medicine found three boys between the ages of 4-10 were in various stages of gynecomastia. They all had lavender and tea tree oils applied via lotion, soap, or shampoo. In one case, a boy displaying breast tissue used lavender-scented soap while his fraternal twin did not use the soap and showed no signs of gynecomastia. In all three cases, discontinuing the use of the products stopped tissue growth.

Both Ramsey’s students and the 2007 study tested chemicals from the oils on human cells, causing endocrine-disrupting activity. This created an imbalance of estrogen and androgen pathway signaling, leading to gynecomastia.

Ramsey did state that there is not enough evidence to confirm the link between the oils and gynecomastia, but did call for larger studies. He cautioned parents on the use of the oils on their children.

Homeopathic remedies such as lavender and tea tree oil continue to grow in popularity, prompting the U.S. Food and Drug Administration to propose more enforcement on alternative treatments. Lavender oil use ranges from treating skin infections to being a mood stabilizer while tea tree oil has been used for inflammation and acne.

BBC reported that Ramsey’s research and results will be presented on March 19 at the Endocrine Society’s annual meeting.