The researchers of a recent study caution about the regular use of lavender and tea tree essential oils (e.g. in lotions or soaps) - that the oils may act as endocrine disruptors (chemicals that disrupt hormones and their actions in the body). Earlier research found a link between regular use of lavender essential oil and tea tree oil and abnormal breast growth in boys - called prepubertal gynecomastia. The condition went away after they stopped using the products.
Now researchers examined 8 common chemical components of lavender and tea tree oils for endocrine disrupting activity in lab tests - and yes, they found varying degrees of endocrine-disrupting activity in the chemicals. The researchers (from the National Institute of Environmental Health Sciences or NIEHS) warn that endocrine disrupting chemicals found in these 2 essential oils are also found in 65 other essential oils.
Note that essential oils are widely available, but they are not regulated by the FDA. Bottom line: No matter the age, avoid prolonged use of lavender and tea tree oil in personal care products, including "aromatherapy" - especially important for children and pregnant women. The results were presented today at the 100th annual meeting of the Endocrine Society (ENDO) in Chicago. From Science Daily:
A new study lends further evidence to a suspected link between abnormal breast growth in young boys -- called prepubertal gynecomastia -- and regular exposure to lavender or tea tree oil, by finding that key chemicals in these common plant-derived oils act as endocrine-disrupting chemicals. Lavender and tea tree oil are among the so-called essential oils that have become popular in the United States as alternatives for medical treatment, personal hygiene and cleaning products, and aromatherapy. Various consumer products contain lavender and tea tree oil, including some soaps, lotions, shampoos, hair-styling products, cologne and laundry detergents.
Male gynecomastia occurring before puberty is relatively rare, but a growing amount of cases have been reported to coincide with topical exposure to lavender and tea tree oil, and the condition went away after the boys stopped using the oil-containing products, Ramsey said. Researchers at the NIEHS, including Kenneth Korach, Ph.D., a co-investigator for the new study, previously found laboratory evidence that lavender and tea tree oil have estrogenic (estrogen-like) properties and anti-androgenic (testosterone inhibiting-like) activities, meaning they compete or hinder the hormones that control male characteristics, which could affect puberty and growth.
Under Korach's direction, Ramsey and his NIEHS colleagues went a step further. From the hundreds of chemicals that comprise lavender and tea tree oil, they selected for analysis eight components that are common and mandated for inclusion in the oils. Four of the tested chemicals appear in both oils: eucalyptol, 4-terpineol, dipentene/limonene and alpha-terpineol. The others were in either oil: linalyl acetate, linalool, alpha-terpinene and gamma-terpinene. Using in vitro, or test tube, experiments, the researchers applied these chemicals to human cancer cells to measure changes of estrogen receptor- and androgen receptor-target genes and transcriptional activity.
All eight chemicals demonstrated varying estrogenic and/or anti-androgenic properties, with some showing high or little to no activity, the investigators reported. Ramsey said these changes were consistent with endogenous, or bodily, hormonal conditions that stimulate gynecomastia in prepubescent boys.
Of further concern, according to Ramsey, is that many of the chemicals they tested appear in at least 65 other essential oils. Essential oils are available without a prescription and are not regulated by the U.S. Food and Drug Administration. Thus, the public should be aware of these findings and consider all evidence before deciding to use essential oils. The NIEHS Division of Intramural Research funded this study through its support of Korach.
Lavender. Credit: Wikimedia Commons