Lavender-Tea Tree Oil-gynecomastia Response to NEJM Article

The New England Journal of Medicine has published (subscription or purchase required) (h/t Tony B) several Letters to the Editor in its June 14 issue regarding the paper "Prepubertal Gynecomastia Linked to Lavender and Tea Tree Oils" originally published earlier this year and extensively covered in the world media and extensively blogged about on the aromaconnection blog. The four letters from six authors make a number of points, including the following pastiche (paraphrased unless in quotes) drawn from all the letters:

Product names were not reported, raising concerns about what was actually present. There was no examination of alternate processes that might have caused the gynecomastia. Traditional uses or these oils have not suggested estrogenic effects. In vitro testing alone is not adequate to indict products. The estrogenic effects reported indicate a very weak effect. The tea tree effects were not separated from the lavender and "There is no rational process that could allow the authors to conclude that tea tree caused the gynecomastia. . ." "the estrogenic activity . . . was dose dependant." The effects became positive at levels at least 600,000 times the level of the positive control. "Testing was far from comprehensive." "The study . . . does not support a causative link . . ." The study was uncontrolled with other agents possibly having a role. ". . . an average 20-kg child would had to have used 40 bottles of shampoo for each application. The claim of a causative link . . . appears to be misleading and unwarranted."

The authors were given the opportunity to reply and fell back on the usual excuses: we used the ingredients list on the bottle; we didn't know about/find other research; some of the critics sell the stuff and therefore are scoundrels; other variables that we ignored might have been a factor; yes, our findings should be interpreted carefully; yes, there should be more research.

Not surprisingly, the publishers of the some 22,700 articles on the original paper that show up on Google appear to have overlooked the new information and discussion. That is because the there was no press release to raise it from obscurity and the limited access of NEJM economics that require payment to read it.