Do essential oils cause endocrine disruption in children?2019-10-08T17:24:13+00:00

Project Description


Through a partnership with the National Association for Holistic Aromatherapy (NAHA) and the Tisserand Institute, the Franklin School of Integrative Health Sciences Research Department / Franklin Health Research Foundation is leading a 3-part research project to investigate the proposed link between lavender and tea tree essential oils and endocrine disrupting outcomes, including prepubertal gynecomastia.

While multiple laboratory studies over the last decade have uncovered potential endocrine disrupting effects of essential oils, this proposed link has yet to be either substantiated or rejected through epidemiological studies.

Without an analysis of the effects of these ingredients within the human body, the safety of these two oils in pediatric products cannot be confirmed scientifically. These studies will be the first to identify the outcomes of the use of lavender and tea tree essential oils in personal care products for babies and children.

This 2-year research project began Fall 2018 and is expected to be completed late 2020. The total cost of the project is $288,000, and it is being funded by the Franklin School of Integrative Health Sciences, the National Association for Holistic Aromatherapy, the Tisserand Institute, through generous industry sponsors, and through generous individual donors.


JUNE 2019: 

  • The Tisserand Institute joins the sponsorship team to fund this research project
  • NAHA hosts a crowd funding project for sponsorship

MARCH 2019: 

  • Development of scientific approach to measurement of lavender and tea tree exposure (study #1) completed.

JANUARY 2019: 

  • Methodology and Research Strategies Finalized
  • IRB Authorization Received


Project underway! NAHA and the FSISH collaborated to launch this 3-part study.

At a Glance:

There are 5


in the scientific literature

linking lavender EO and/or tea tree EO to endocrine disrupting outcomes.

There are 0


in the scientific literature

concluding that pure lavender and tea tree are safe for use with children.


is the total cost

This Study

for this 2-year and 3-part clinical research project.


of the studies

linking these oils

to endocrine disruption are insufficient to establish causation.

Over 6,000


will participate

in this research project.

Questions About the Project:

What kind of study is this?2019-04-17T16:26:26+00:00

This project consists of three separate studies:

  • Measurement Instrument Creation & Validation
  • Cross-Sectional Study
  • Case-Control Study

The first and most important step was to develop a verified way to measure exposure to these oils in children. This is accomplished by creating and then testing a measurement instrument. In this case, the instrument is a questionnaire which was found to be highly effective at both identifying and quantifying exposures to lavender and tea tree oils over a period of 15 years. The first study is already finished and in the process of publication.

The next two studies are taking place simultaneously and are using this measurement tool to evaluate endocrine disruption outcomes in children who were exposed to these two oils. The case-control study is specifically looking at boys with confirmed cases of prepubertal gynecomastia and the cross sectional study is looking at both sexes and a wide range of endocrine disrupting outcomes.

If either of these two oils are associated with endocrine disrupting activity in children, this set of studies will find where that association exists. Perhaps it finds that a certain brand of products is linked to the effects. Or perhaps it finds that the effects are only found in a certain region or in children of a certain race. If there is a link, it will be found. If there is not a link, this project provides the first actual scientific evidence that these two essential oils do not cause these outcomes in children.

What kind of oils are you using?2019-04-17T16:42:53+00:00

This set of studies will look at all forms of lavender and tea tree essential oil through all methods of exposure: medicinal, neat or undiluted, as ingredients in skincare, and even as ingredients in household products such as laundry soap. By the end of this project, we will have found any link that may exist and be able to specify exactly where it is found. For example, if adulterated oils in shampoo are where this happens, we’ll know. Or if high quality oils in laundry soap are the real link, we’ll find it. And if no link exists at all, we’ll find that as well.

Which chemicals are you testing?2019-04-17T16:42:59+00:00

This project isn’t testing isolated chemicals. We’re looking at how these oils are used in personal care products and other environmental exposures, which is often through the whole oil as an ingredient. These two studies will provide the first ever evidence regarding the safety–or lack thereof–of these two complete essential oils as ingredients.

Are you looking at all of the other ingredients in skincare products?2019-04-17T16:43:20+00:00

The purpose of this research project is not to find the cause of all unexplained cases of prepubertal gynecomastia or endocrine disrupting outcomes in children. It is to examine whether or not lavender and tea tree essential oils are linked to these outcomes.

Identifying the cause is definitely a research priority, but identifying a different ingredient in skincare products that may be associated would not eliminate lavender and tea tree essential oils as possible causes as well. There can be (and are) multiple causes of endocrine disruption in children. The purpose of this research is only to examine whether or not lavender and tea tree oils have these effects.

Are you looking at the possibility of oils leaching chemicals from the plastics?2019-04-17T16:47:58+00:00

This project focuses on whether or not these two oils can legitimately be linked to endocrine disrupting outcomes in children. Should this project find that these oils can be linked, then future projects will include identifying why those oils are linked. However, should this project find that these oils cannot be linked to these outcomes, then whether or not oils are leaching chemicals from plastics is irrelevant to the question of endocrine disruption in children.

The purpose of taking the research beyond the lab and into human populations is to get to the root of the claim that these oils are harmful to children. Laboratory studies about the interactions between the oils and their containers are fascinating, but insufficient to answer the underlying question of safety. The goal of this project is to get directly to the claim and establish with certainty whether or not these oils are linked to negative outcomes in children, not petri dishes.

Isn’t the proposed link explained by oil quality?2019-04-17T16:27:07+00:00

Perhaps. Perhaps not. There is a widely held belief in aromatherapy that adulterated or poor quality oils are harmful while pure essential oils are perfectly safe. But as it stands, that view is nothing but perception. There is no solid scientific evidence that substantiates that belief. This project will do exactly that. If there is a link, we will find it and pinpoint exactly where it comes from and who it affects. But until this work is complete, there is nothing but perception and opinion to support the idea that natural, pure lavender and tea tree oil are never going to cause endocrine disruption in children.

I thought the 2007 study was debunked a long time ago.2019-04-17T16:27:01+00:00

The concept that this question is due to a single study that was long-ago debunked is a widely held impression but unfortunately, inaccurate. The 2007 study certainly raised some questions, but these were addressed in subsequent studies. As of 2019, there are a total of 5 accepted studies that suggest that these oils produce endocrine disrupting outcomes, and a total of ZERO studies that produce evidence to the contrary.

This research is a critical next step to take the existing claims out of the lab and into human populations. If there is no link, this project will provide the scientific evidence that is now 12 years overdue.

Is this REALLY necessary?2019-04-17T16:26:17+00:00

An enthusiastic YES! While most of the aromatherapy community believes these two oils to be unrelated to endocrine disrupting outcomes in children, there is not currently any factual evidence to support that idea. Absolutely nothing in the scientific literature can be used to substantiate that belief.

When the only evidence of safety exists in the form of opinions from those within an industry, there is a problem.

It is up to the integrative health community to face this concern head-on and investigate these claims. If a link exists, it needs to be found. We need to 1) find whether or not it exists,  2) find what products/brands are linked to the effects and finally, 3) identify the demographics of children who are susceptible to these effects. If a link does not exist, that needs to be substantiated through legitimate scientific research.

It is simply not enough in modern integrative health to refute serious claims of harm through nothing but opinions from those within an industry. We have to take these claims seriously and back up those opinions with evidence. That’s what this project accomplishes.


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