Asked by: Richard Rowland, Chesterfield
A 2007 study at the US National Institute of Environmental Health Sciences found some evidence that both tea tree and lavender oils are endocrine disruptors.
The effect was investigated after three otherwise healthy boys were diagnosed with pre-pubescent breast enlargement. The boys had used hair and skin products containing tea tree and lavender. The oils don’t appear to alter the levels of hormones in the bloodstream, but they may affect the way cells respond to hormone signals. This has been partially confirmed by in vitro studies on human breast tissue cells.