lavender and tea tree oils, whiff of lavender, lavender oil

Lavender and tea tree oils are popular ingredients in body care products. But might they have some unintended consequences? A new study presented at the Endocrine Society Annual Meeting in Chicago on March 19, 2018, hints at some disturbing possibilities.

How Do Lavender and Tea Tree Oils Affect Hormones?

Case reports have suggested that young boys exposed to concentrations of compounds from these plants may develop enlarged breasts (see below). Consequently, the researchers investigated eight compounds common to both lavender and tea tree (Melaleuca alternifolia).

Eight Compounds Tested for Hormonal Effects:

  • Eucalyptol
  • 4-terpineol
  • Dipentene/Limonene
  • Alpha-terpineol
  • Linalyl acetate
  • Linalool
  • Alpha-terpinene
  • Gamma-terpinene

Each of these compounds promoted estrogen activity and inhibited androgen activity in the human breast cancer cells used for the test.

Lavender and tea tree are not the only plants that make these compounds. They are widely distributed in the plant world, suggesting that more research on benefits and risks is urgently needed.

This is not the first research to indicate that lavender and tea tree oils may block the action of male hormones (androgens). This line of research was stimulated by the case reports of young boys who developed noticeable breasts.

Does Lavender Make Little Boys Grow Breasts?

Q. You wrote some time ago that male breasts grew after contact with lavender (shampoo, soap, etc.) and urged caution. I have just read in Time magazine (April 4, 2016) that “in Germany, lavender tea has been approved as a treatment for insomnia.”

Given the first mentioned concern, could you comment on this?

Do Boys Grow Breasts When They Are Exposed to Lavender?

A. The story on lavender is complicated and controversial. Several years ago three case reports were published in The New England Journal of Medicine (Feb. 1, 2007) linking the use of lavender and tea tree oil skin products to breast development in young boys. The authors raised the possibility that these natural products might have had estrogenic activity.

Needless to say, a lot of people got excited about this hypothesis. A study conducted in female rats exposed to lavender oil concluded that it “gave no evidence of estrogenic activity” (International Journal of Toxicology, Mar-Apr., 2013). Several readers wrote that we should revise our opinion based on this research.

But a recent report in the Journal of Pediatric Endocrinology and Metabolism (Jan 1, 2016) presents three new cases of breast development in young boys exposed to lavender.  This doesn’t seem to be a common occurrence, but until the question is settled, we’d recommend that parents not use lavender-containing products on boys. Given the research that tea tree oil may also act as a natural hormone disruptor, we’d also suggest limiting the use of this product for children.

Lavender for Insomnia:

Taking lavender orally, whether in a tea or a capsule, may help with insomnia, but we remain uncertain if doing so would have hormonal side effects. We don’t think that aromatherapy utilizing the fragrance of lavender to help a person get to sleep is likely to pose a problem.

One reader, Cathy, commented on this topic:

“I think you have to compare the amount you get in a tea (and the frequency of use) to the amount you get in an essential oil (and the amount of exposure). Essential oils are made by steam distillation of a very large amount of plant material to render a very small amount of oil. They cannot be made by most people at home but they seem to be everywhere – soap, toothpaste, lotions, laundry products – in amounts it is impossible for the consumer to compute – so it is hard to avoid them. They can be absorbed by the respiratory system and they also have the power to enter through the skin. I make contact with them just by walking down the street, when I smell my neighbors’ dryer sheets!

“Companies in the essential oil marketing business get into trouble frequently with the FDA for making claims that the oils cure diseases. And we’ve all heard they are anti-viral, anti-fungal, and anti-microbial, as many plants are. Aren’t those claims crucial to that business? If you encounter something so powerful and concentrated as to cure diseases so readily, prepare to suffer side effects. Doesn’t this make them drugs? So I think they should not be used casually or without awareness, as in all these scented products.

“Some believe that these oils are endocrine disrupters. That is what the cited cologne study indicates. I can’t help but believe it. I know two young women who are in the essential oil business – one distills, sells, demonstrates, and tests them, and the other makes soap with them. Both of these ladies have had problem pregnancies and births since they got into these businesses (but normal ones before).

“I have decided to get essential oils out of my life. But I will keep, use and enjoy my two lovely lavender plants.”

Get The Graedons' Favorite Home Remedies Health Guide for FREE

Join our daily email newsletter with breaking health news, prescription drug information, home remedies AND you'll get a copy of our brand new full-length health guide — for FREE!

  1. Don

    I put a drop of lavender on my wrist before I turn in. I think it improves my sleep. No other effects noted.

  2. Jan

    Here in Provence essential oils are part and parcel of the fabulous French health service. The extraction of lavender is a highly regulated process unlike the Chinese version. I suggest you check to see where your lavender comes from rather than suggesting all lavender is compromised.

  3. Lauren

    I use Young Living oils, and I agree, they are very potent, and should be used cautiously. I would love to hear of more research in the future regarding essential oils. I have had good luck with them treating many things, without the side effects of conventional medicine.
    This article is the first I’ve seen in several years about the connection between lavender and hormone disruption. I would love to hear more on this subject!

  4. Mary Jane

    In the 19th century (and perhaps other times), lavender was a scent used by men (not women). It was assumed that it had a calming effect on the male libido. Given the havoc wreaked today by rampant testosterone, I think there is nothing wrong with exposing males to lavender.

  5. Susie
    Buffalo NY

    This study is definitely of interest and hopefully, more precise research will be coming soon.
    Superior quality essential oils are life savers and changers for many people. One drop of a quality peppermint oil in a cup of water has the therapeutic equivalent of drinking 128 cups of peppermint tea. Yes, oils can be very potent!
    A previous reader is incorrect in stating that dryer sheets emit essential oil smells. The smell is from artificial chemicals and have been linked to respiratory ills and potential cancers.
    I don’t feel it is prudent to paint a wide brush and blame essential oils for a litany of problems. Further research is needed and only superior quality oils should be used.

  6. ariel

    it barely mentioned tea trea oil and then went into lots of information on lavender.
    I am now concerned as my toothpaste contains tea tree oil. Is it safe?

  7. Anne

    Interesting, but this seems to be about lavender. Would you please explain if Tea tree oil (I use a face wash with it) has side effects? Many thanks!

    • Terry Graedon

      The tea tree oil also had the anti-androgen, estrogen-promoting effects. Used in sensible amounts, it isn’t likely to pose a big danger to adults. But it probably should not be used by children.

  8. Marilyn B.

    I am much more concerned about pesticides as endocrine disruptors. They are much more pervasive than lavender essential oil. People ingest them all day every day.

  9. Barbara

    Are tea tree oil hair conditioners safe, or should they be avoided?

    • Terry Graedon

      Based on this research, I’d avoid using tea tree oil products on children.

      • Jan

        As a nurse and clinical aromatherapist, I am always concerned with the overuse and unsafe use of essential oils, often promoted by companies, social media, and distributors who lack quality essential oil education. Unfortunately, preliminary information released linking Tea Tree and Lavender essential oils to gynecomastia appears to have been sensationalized. An organization representing the Australian Tea Tree industry released a statement of concern with the study, including information that neither Lavender or Tea Tree were studied as a “whole essential oil” – only certain chemical components were used. Some of these same chemical components are also in citrus oils. You will find a link on their website Other essential oil researchers have also identified concerns, but until the entire study is published, we won’t know the full details. I agree that we should all use caution until we know more, but more importantly it is always wise to use extremely small amounts of essential oils in general.

What Do You Think?

We invite you to share your thoughts with others, but remember that our comment section is a public forum. Please do not use your full first and last name if you want to keep details of your medical history anonymous. A first name and last initial or a pseudonym is acceptable. Advice from other commenters on this website is not a substitute for medical attention. Do not stop any medicine without checking with the prescriber. Stopping medication suddenly could result in serious harm. We expect comments to be civil in tone and language. By commenting, you agree to abide by our commenting policy and website terms & conditions. Comments that do not follow these policies will not be posted. Learn how your comment data is processed.

Your cart

Shipping and discount codes are added at checkout.