Gynecomastia is a rare condition where breast tissue grows in boys or men due to an imbalance of estrogen and testosterone. In 2007, three boys reportedly had the condition at the same medical facility. They allegedly were all using topical products containing lavender and tea tree essential oils. The doctor had them stop using these products and their gynecomastia went away. The doctor concluded that tea tree and lavender oil were estrogenic.
However, as experts point out, a sample of three boys is not a significant sample size. The products were not identified, nor the ingredients in these products. So, we can’t be certain that they even contained essential oils! Additionally, many of the products were wash off products or used in small quantities, which would not allow enough essential oils to be absorbed into the skin and into the body to cause any significant effect. The lavender smell could have come from a fragrance oil, which contained phthalates, a known hormone disruptor, or it could have been another ingredient altogether. Many synthetic preservatives contain parabens and parabens are potential endocrine disruptors.
In 2007 a laboratory experiment was also conducted in test tubes using a couple of chemicals found in tea tree and lavender essential oils on breast cancer cells. It was concluded that lavender and tea tree oil have estrogenic and anti-androgenic properties. Well, experts again pointed out the flaws with this study. Because it happens in a test tube doesn’t mean it will happen in the human body. And they used breast cancer cells, not the normal cells that most of us are carrying. Additionally, essential oils are known to leach phthalates out of plastic and guess what? They used plastic containers in this study.
In 2016 and 2019, studies again claimed that the lavender containing products caused gynecomastia. Again, the products used were mostly wash off and there was no evidence they contained lavender. They said the products were purple and smelled like lavender. Real scientific! Lavender oil isn’t purple but synthetic colours are and they contain carcinogens. Again, they used small groups of 3-4 children. It’s unbelievable to me that such bad science is still being conducted.
Why would someone repeat such bad science? Perhaps some were afraid of the natural health movement gaining momentum. Knowing that the media likes to sensationalize these stories, they hoped to curb that momentum.
In 2021, a proper study was done by Jessie Hawkins, which included 556 children, using the complete essential oils and no causation was found.
However, many websites (even respectable ones) reported the earlier findings and have not updated them to reflect this latest study. If you do a search on the web, the first five pages or so give you results saying that lavender and tea tree cause breast growth in boys. And these studies are still being referenced in other studies.
If you’d like to read more, look for articles published by Robert Tisserand, the Tisserand Institute, Dr. Robert Pappas or Salvatore Battaglia.