I’ve heard that lavender oil can cause breast swelling in young boys? Should I not use this on my son?

The data regarding lavender oil and gynecomastia (breast swelling) in young boys is very hotly contested as evidenced by the significant number of response comments in New England Journal of Medicine and a response article entitled “Lack of evidence that essential oils affect puberty” published in the journal of Reproductive Toxicology.

Though there were three case reports said to link lavender and tea tree oil to gynecomastia, the authors didn’t note the full list of ingredients in the products cited or account for xenoestrogenic contaminants including plasticizers, pesticides and herbicides. Then in experiments they obtained lavandula officinalis from a chemical company not an essential oil company. To determine if the lavender oil was estrogenic and androgenic in cell culture, they diluted it in DMSO and cultured in polystyrene plates both of which are well known to modulate both estrogens and androgens. They also selected to do a cell culture instead of a uterotropic assay (a test to determine if uterine lining grows in response to a chemical) and this has been widely criticized because uterotropic assays are considered the gold standard testing method. The authors themselves admit that more research is needed to determine causality.

In my professional opinion, lavender oil and gynecomastia is a consideration, but would not preclude me from using in a young male.