Lavender and tea tree oils found in toiletries may have endocrine-disrupting effects on boys, according to a report by researchers from the National Institute of Environmental Health and Sciences (NIEHS).
The report includes case studies of three boys aged 4, 7, and 10 years who developed enlarged breast tissue after regular use of soap, skin lotion, shampoos or styling products containing lavender or tea tree oils (Henley D et al. N Engl J Med. 2007;356:479-485). The boys, who were otherwise healthy, had normal hormonal levels when they were diagnosed. The symptoms subsided in all three boys after they avoided products containing lavender or tea tree oils for several months.
Kuehn BM. Herbal Risks for Boys. JAMA. 2007;297(12):1307. doi:10.1001/jama.297.12.1307-c