The dark side of lavender oils

The lavender and tea tree oils found in some soaps, shampoos, hair gels and body lotions can produce enlarged breasts in boys, according to a study published Wednesday.

These plant oils were linked to abnormal breast development in three boys. The effect was reversed when they stopped using the products, according to Dr. Clifford Bloch of Pediatric Endocrine Associates in Greenwood Village, Colo., and colleagues.

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 estrogen.

“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.”

It is common for boys to develop temporary breast enlargement during puberty, but the condition is rare in young boys, Bloch’s team wrote. They found the problem in three otherwise healthy boys -- ages 4, 7 and 10.