BOSTON: The lavender and tea tree oils found in some soaps, shampoos, hair gels and body lotions can produce enlarged breasts in boys, researchers reported on Wednesday.
These plant oils were linked to abnormal breast development in three boys, which was reversed when they stopped using them, Dr Clifford Bloch of Pediatric Endocrine Associates in Greenwood Village, Colorado, and colleagues reported.
They said their study, published in Thursday's issue of the New England Journal of Medicine, suggested these oils can act in ways similar to the hormone oestrogen.
"This report raises an issue of concern, since lavender oil and tea tree oil are sold over the counter in their 'pure' form and are present in an increasing number of commercial products, including shampoos, hair gels, soaps, and body lotions," the researchers wrote.
"Whether the oils elicit similar endocrine-disrupting effects in prepubertal girls, adolescent girls, or women is unknown."
While it is very common for boys to develop temporary breast enlargement as they go through puberty, the condition is very uncommon in young boys, Bloch's team wrote.
They found the problem in three otherwise healthy boys – ages 4, 7 and 10.
"I got wind of it because I was given a clue by a patient," Bloch said in a telephone interview.
That case involved the 4-year-old "who was using absolutely nothing on his skin except a lavender oil preparation that his mother had obtained from a homeopath. She used to rub it on his chest and body every night" because lavender, in alternative medicine circles, is supposed to have healing properties.
Several months after the boy stopped getting the "healing balm," his breasts returned to normal.
Meanwhile, Bloch then began to see lavender crop up in other cases, including the 10-year-old, who was using a hair styling gel and shampoo that contained both lavender oil and tea tree oil, and the seven-year-old, who had been using lavender-scented soap and skin lotions.
In laboratory tests, scientists at the National Institute of Environmental Health Sciences in North Carolina found that both substances can mimic the action of the female hormone oestrogen and block male hormones that control both masculine characteristics and inhibit the growth of breast tissue.
[from stuff.co.nz]