The New England Journal of Medicine first reported (12 years ago) the case of 3 boys who developed breast growth coinciding with the use of skin care products that contained lavender oil and tea tree oil. The breast growth (known as gynecomastia) subsided after stopping the use of these products.
In another case, a 3-year-old girl had been regularly bathed with a Calming Baby Bath that contained lavender and chamomile, and then developed breast growth and tenderness. This finally subsided 6 months after stopping the soap.
Multiple other reports have now described early breast development in both boys and girls. Over 20 cases were described at a single hospital in Miami, and in 16 of these cases, regular exposure to lavender (via soaps, lotions, and essential oils) was suspected to be the case. In all cases, the breast growth subsided within 3-6 months of stopping the lavender products.
Why would a natural ingredient be linked to early breast development in children?
It is not known why these products have been linked to early breast growth in some children. Researchers have since studied these compounds in the laboratory, looking specifically at some of the chemical components of these essential oils.
They suspect that some of the compounds found in these essential oils may act as endocrine disrupting chemicals. In their research, they found that some compounds in the laboratory have effects that interfere with the endocrine system. Some compounds had estrogenic activity (female hormone effects) and anti-androgenic activity (anti-male hormone effects).
Researchers have only begun investigating these effects, however, and that means there's still much that we don't know. Are these effects due to the fact that some of these natural skin care ingredients are still highly processed and therefore behave differently than they would in their natural state? And why is it that some children are affected, but many others seem just fine? And finally, are there hormone changes occurring that aren't as visible as the early breast growth? We just don't know at this point in time.