Prepubertal Gynecomastia Linked to Lavender and Tea Tree Oils

TLDR

Male prepubertal gynecomastia is usually idiopathic. The study aimed to identify causes of gynecomastia in three healthy prepubertal boys with normal steroid levels. The authors examined these boys to investigate potential etiologies. Gynecomastia in all three boys appeared with use of lavender and tea tree oil products, resolved after stopping them, and in vitro studies showed these oils have estrogenic and antiandrogenic effects, supporting that repeated topical exposure likely caused the condition.

Abstract

Most cases of male prepubertal gynecomastia are classified as idiopathic. We investigated possible causes of gynecomastia in three prepubertal boys who were otherwise healthy and had normal serum concentrations of endogenous steroids. In all three boys, gynecomastia coincided with the topical application of products that contained lavender and tea tree oils. Gynecomastia resolved in each patient shortly after the use of products containing these oils was discontinued. Furthermore, studies in human cell lines indicated that the two oils had estrogenic and antiandrogenic activities. We conclude that repeated topical exposure to lavender and tea tree oils probably caused prepubertal gynecomastia in these boys.