08/08/2026
Great research on Lavender and Tee Tree oils showing they are not endocrine disruptors. Thank you to everyone who did all of this work!
NAHA has been privileged to partner with Dr. Jessie Cavanaugh to examine the safety and efficacy of essential oils, particularly for use on vulnerable populations. To date, five studies have either been completed or are in progress.
The first study examined the potential relationship between lavender and tea tree oils and endocrine disruption related to prepubertal gynecomastia. The study confirmed that lavender and tea tree oils are unrelated to endocrine disruption and are safe to use in children's products. "This study was the first and only to scientifically evaluate these claims, and included over 550 children" (Franklin Health).
A NAHA YouTube webinar with Dr. Jessie (Hawkins) Cavanaugh presenting the results of the study, Lavender & Tea Tree Oils as Endocrine Disrupters, can be found here: https://www.youtube.com/watch?v=vJ3KgA9K15k
The claim that lavender and tea tree essential oils disrupt hormones traces back to a single 2007 case report describing three boys with breast growth who had used personal care products said to contain these oils. The products themselves were never tested, the essential oil content was never confirmed, and in one case a fraternal twin used the same lotion and never developed any symptoms at all. What supported the theory was in vitro testing, oils dropped directly onto isolated cells in a lab dish, which is nothing like how skin absorbs a diluted oil in daily use.
Robert Tisserand, along with researchers Christine Carson and Tony Larkman, published a detailed review of the case data pointing out that any hormonal activity detected in vitro was estimated to be at least 10,000 times weaker than natural estradiol, and that the boys' actual exposure to lavender or tea tree, especially through wash off products like shampoo and soap, would have been far too brief and dilute to reach that threshold in the body.
The theory sat untested for over a decade until NAHA partnered with Dr. Jessie (Hawkins) Cavanaugh of Nutraceuticals Research Institute (formerly Franklin Health Research) to run the first real epidemiological study on the question, following more than 550 children to evaluate their lifetime exposure to lavender and tea tree oils against their health outcomes.
The study, published in the International Journal of Pediatrics and Adolescent Medicine in October 2021, found no evidence linking use of either oil to endocrine disruption in children. This is the piece that had been missing from the conversation for years: real population level data rather than isolated cases and test tube extrapolation. It found that children exposed to these oils have hormone related developmental outcomes consistent with the general population.
What media sensationalism transformed into a frightening myth was finally debunked: pure lavender and tea tree oil, used as they have been for generations, are not endocrine disruptors.
Scientific research is a critical tool that allows us to better understand the safety and efficacy of essential oils. NAHA is committed to furthering essential oil research and will continue supporting relevant research projects. We would like to personally extend our heartfelt gratitude to all of the wonderful NAHA members who make studies like these possible through your support!
For the Lavender Tea Tree study, we express special appreciation to the major donors and contributors: The Franklin Health Research Foundation which conducted the study at cost, the National Association for Holistic Aromatherapy (NAHA), the Tisserand Institute, and the Australian Tea Tree Industry Association.
With gratitude,
Annette George Davis, NAHA President
Jennifer JennScents Pressimone, NAHA VP
Rose Chard, NAHA Secretary
Eric Davis, NAHA Treasurer
Kelly Holland Azzaro, NAHA PR
Sharon Louise Chapman, NAHA DC
Research Links:
https://naha.org/naha-blog/prevalence-of-endocrine-disorders-among-children-exposed-to-lavender-essent
https://pmc.ncbi.nlm.nih.gov/articles/PMC9152575/
https://www.attia.org.au/news/scientists-confirm-essential-oils-unrelated-to-hormone-disruption
https://naha.org/naha-blog/neither-lavender-oil-nor-tea-tree-oil-can-be-linked-to-breast-growth-in-you
https://www.drjessiecavanaugh.com/about-5