Scientists Confirm: Essential Oils Unrelated to Hormone Disruption

  • Epidemiological Research Debunks the Long-Held Myth That Lavender and Tea Tree Oils Cause Endocrine Disruption in Children.
  • Results of a study by Franklin Health Research Centre (USA) conclusively rule out Tea Tree Oil as an endocrine disrupter.

The results of this large prospective epidemiological study conducted in the USA conclusively rules out any purported links between Tea Tree Oil and breast development in young boys, a medical condition called gynecomastia, also known as premature thelarche in young girls.

Previous studies by close associates Henley & Korach (2007), Diaz (2016) and Ramsey & Korach (2018) purported a causal link between Tea Tree Oil, Lavender Oil and endocrine disruption in children.

Those studies were refuted by many others including Carson et al (2014) either due to limited data, potential contamination of experimentation methods or using products which did not contain either essential oil. However, without solid epidemiological evidence to refute these claims, the sensationalist headlines remained and were widely publicised.

In 2007 Henley et al called for further studies saying “Until epidemiologic studies are performed to determine the prevalence of gynecomastia associated with exposure to lavender oil and tea tree oil, we suggest that the medical community should be aware of the possibility of endocrine disruption and should caution patients about repeated exposure to any products containing these oils.”

That solid epidemiological evidence is now in hand and the results are clear. A paper, published by Hawkins et al in the International Journal of Pediatrics and Adolescent Medicine, titled “Prevalence of Endocrine Disorders Among Children Exposed to Lavender Essential Oil and Tea Tree Essential Oils” has unequivocally confirmed that no such association with these Essential Oils exists. The
authors stated:

“This study provides evidence that lavender essential oil and tea tree essential oil are safe ingredients in formulations for personal care products used on children.”

The authors concluded:

“The proposed links between these ingredients and endocrine disruption cannot be substantiated in epidemiological studies.”

The cross-sectional, prospective study was designed to identify the lifetime prevalence of endocrine disruption, including but not limited to prepubertal gynecomastia and precocious puberty, among children who are exposed to Lavender and Tea Tree essential oils, compared with the prevalence in the general population. A study cohort of 556 children, aged 2 to 15 years old was enrolled, powering the study’s statistical analysis above a 95% confidence interval of 2%.

The study confirmed the following:

  • Prevalence of endocrine disorders among children exposed to these ingredients (Tea Tree and Lavender) is consistent with the general population and proposed links between these ingredients and endocrine disruption cannot be substantiated in epidemiological study.
  • Warnings raised by Henley, Ramsey, Diaz, and Korach (National Institute of Environmental Health Sciences) in publications since 2007 purporting the link between endocrine disruption and essential oils (and their individual constituents) were premature, caused undue concern, and erroneously misled the medical community and countless concerned parents.

This exhaustive study by Hawkins et al. concluded that Tea Tree Essential Oil is a safe ingredient and presented no risk of endocrine disruption in formulations for personal care products used on children.

“This is great news as it once and for all clears up misinformation about Australian Tea Tree Oil, allowing parents to feel comfortable using products that contain this highly efficacious natural ingredient.”  said Tony Larkman – CEO, ATTIA Ltd


1. Dr Jessie Hawkins, who led this research released a statement confirming the findings to debunk
the long-held myth that Lavender and Tea Tree Oils cause endocrine disruption in children:

2. Henley et al (2007) “Prepubertal gynecomastia linked to lavender and tea tree oils”:

3. Carson et al (2014) “Lack of evidence that essential oils affect puberty”:

4. Diaz et al (2016) “Prepubertal gynecomastia and chronic lavender exposure: report of three

5. Ramsey et al (2018) “Essential Oils and Health”:

6. Hawkins et al (2020) “The relationship between lavender and tea tree essential oils and pediatric
endocrine disorders: A systematic review of the literature”:

7. Hawkins et al (2021) “Prevalence of endocrine disorders among children exposed to Lavender
Essential Oil and Tea Tree Essential Oils”: