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Essential Oil Safety

Updated: Oct 16, 2022

Truths of Essential Oil & Research Studies

By Annie Mascia

Recently, I had the privilege of listening to a webinar from the Franklin Institute of Wellness on scientific research studies. The lecture was based on how scientific research is conducted in regard to essential oils (EOs). Some of you may remember the tumult that ensued a number of years back when it was "found'' that boys who used products with tea tree essential oil and/or lavender essential oil grew breast tissue.

After medical visits, it was determined that these boys had been using body products made with tea tree (Melaleuca alternifolia) essential oil and/or lavender (Lavandula angustifolia) essential oil. The doctor, diagnosing the boys with Gynecomastia (the official term for breast growth in males), suggested changing the shampoo/soap the children used and after a few months, purportedly the problem disappeared. So a connection was made between the above mentioned essential oils and hormone disruption. The doctor then alerted the National Institute of Health (NIH) as to his findings, as he should have.

You may think that in these few cases, essential oils must be the cause, however, the determination of the cause it's not so cut and dried. What was not mentioned is that some prepubescent boys have naturally occurring Gynecomastia, which usually resolves itself within 6 months. It turns out that there was never an actual study to truly verify if those essential oils actually caused Gynecomastia.

“This raises the question of whether those warnings were issued prematurely as there is no current epidemiological or clinical evidence of a causal relationship between prepubertal gynecomastia or any other form of endocrine disruption and the use of essential oil-based personal care products.(1)”

What does this mean? Should you stop using essential oils? My best advice is to first take purported statements with a grain of salt. One single study or a notification from one or two doctors is never enough to show proof - quality of research plays a huge part.

To carry out an unbiased, scientific study, simplicity is not usually on the books and to top it off, not so easy to conduct. There are a number of mitigating factors which we will get to in a minute. The fact is, science isn't used to create proof, but instead is meant to show a correlation, such as smoking and lung cancer. An actual scientific study also needs a decently sized portion of the human population to test.

To circle back around to EOs & Gynecomastia, in a verifiable research study, the product(s) the boys used which allegedly created the effects of gynecomastia, would have had to be reintroduced in the subjects to verify the return of Gynecomastia. Since this and other procedures of a research study were never carried out, no study was actually conducted.

The real questions and issues have never been resolved and questions remain:

  • Were the occurrences of Gynecomastia related to the products and the essential oils?

  • Was it an environmental issue?

  • Or was it a temporary but natural hormonal condition that happens with some boys?

In order to truly understand if tea tree and lavender, and possibly other essential oils, are hormone disruptors a very controlled study has to be carried out. What has actually been tested to date are some chemical components found in some essential oils such as Linalool”, Linalyl acetate*, 4-terpineol*, Limonene, Eucalyptol, and others.

In lab tests, some of the components have shown little demonstrative activity as estrogen and anti-androgen activity in lab tests(2). When essential oils are broken down and studied, the results never tell the whole story. Chemical components of essential oils have been dissected in lab studies to be tested against cancer and many many other diseases. Individual chemical components actually ruin the unity and healing power of a whole, balanced essential oil - a balance of chemicals that function in symmetry to protect the plant it lives in.

Another portion of research involves human studies and a look at the following:

  • Dose-response assessments (such as how much exposure is safe, what is the threshold level)?

  • Do environmental factors play a part?

  • Are there any other influences that would have affected these children?

  • What were the other ingredients in the products they used?

  • Exposure assessment (How many were exposed?)

  • Were the Essential Oils adulterated? (The product(s) would have to be GC/MS tested for adulteration)

So let's remember not to jump to conclusions. Continue to use and enjoy your essential oils in a safe manner. If there are ever any issues, such as skin irritation, stop using the oils and consult a trained professional or a doctor if necessary.

*Chemical components found in Lavandula angustifolia and Melaleuca alternifolia

Find the Franklin Institute of Wellness here:


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