Concerns Surface Over Essential Oils

Endocrinologists and aromatherapists are at odds over whether lavender and tea tree essential oils cause ‘moobs.’ More consumers are talking to their doctors about it.


Illustration by Paul Haggard

Although they have been popular among Bay Area residents for decades, essential oils are taking up increasing amounts of space in the medicine cabinets of mainstream American homes due to a combination of wellness trends and aspirational lifestyle brands like Gwyneth Paltrow’s company Goop. Those looking to practice self-care in bulk can now even purchase starter sets at Costco. Yet as essential oils proliferate, they face a greater level of scrutiny from the medical community. The safety of lavender and tea tree oils is an ongoing matter of debate between endocrinologists and leaders of aromatherapy institutes.

J. Tyler Ramsey, a post-baccalaureate fellow for the National Institute of Environmental Health Studies, made waves at the Endocrine Society’s annual meeting in March 2018 when he presented a study suggesting a link between the chronic exposure to lavender and tea tree essential oils and the development of breast tissue in young boys — a condition called prepubertal gynecomastia, more colorfully referred to as “moobs.”

The study was a follow-up to the work of Kenneth Korach, a senior investigator at the NIEHS who in 2007 published a controversial study drawing similar conclusions. Korach decided to run experimental evaluations on the effects of lavender and tea tree oils when a pediatric endocrinologist from Denver, Dr. Clifford Bloch, contacted him about a bizarre observation: A clinical head at Bloch’s practice identified that the common factor between a group of at least seven patients that were displaying prepubertal gynecomastia was use of soaps and shampoos that contained lavender and tea tree oils.

Bloch and his team noted that when the patients ceased the use of the products, the symptoms fully resolved in a matter of weeks.

Intrigued, Korach set out to study the effects of the essential oils on isolated cells. He and his team exposed mammalian cell lines to lavender and tea tree oils and then observed androgren and estrogen receptor stimulation in the cells, the hormones responsible for the expression of male and female characteristics, respectively. The findings confirmed Bloch’s suspicions: The essential oils generated hormone responses. “Essentially, the boys were getting what I like to call a ‘double whammy’ of abnormal hormonal activity,” said Korach. Not only were the oils creating more estrogenic activity in the cells, but they were also stifling androgenic levels as well, which can lower testosterone production in the human body.

Some might be tempted to set their lavender products ablaze, but pump the brakes. Korach noted that the anti-androgenic properties only took affect when the concentrations of androgen were low, mimicking those of a prepubescent boy. “As far as adult males,” said Korach, “any kind of exposure would probably not have much of an impact, because the normal adult circulation [of androgen] would be so much higher.” Adult females are unlikely to experience endocrine disruption from these two essential oils for the same reason.

But further clinical observations suggest that young girls might face similar risks as young boys when it comes to chronic exposure to lavender and tea tree oil. After Korach’s study was published, Bloch linked several cases of premature breast development in young female patients, or thelarche, to similar products. “One of the cases was a young girl who was developing breast tissue at around 1 year old,” Korach said. Another female patient displayed symptoms after consistent exposure to lavender oil from a diffuser on her teacher’s desk. When the products were removed, the conditions improved.

Korach’s study received pushback from holistic health practitioners and scientists associated with tea tree oil companies. In letter to The New England Journal of Medicine, James. L. Kurtz, then an employee of Melaleuca, a company that makes and markets home products that contain tea tree oil, expressed dissent over the decision to publish the findings. He claimed that the very small number of reported cases of gynecomastia was discordant with the enormous volume of products containing tea tree oil that his client sold — in the magnitude of 123 million bottles a year.

Korach concedes that there may be a genetic component that makes some children more susceptible to the negative effects of exposure over others, which might account for this discrepancy. Endocrinologists across the country continue to contact him with reports of similar findings. Dr. Alejandro Diaz, a pediatric endocrinologist at the Nicklaus Children’s Hospital in Miami, came across Korach’s study when it was first published. When he moved to Miami in 2009, he noticed at least 16 cases of early breast development in young boys and girls. He started asking his patients about their use of essential oils and discovered that many were using perfumes and colognes containing Agua de Violetas, a water-based cologne containing lavender. He detailed three cases in the Journal of Pediatric Endocrinology in 2016.

Several certified aromatherapists in the Bay Area reject the legitimacy of these reports and claim that clients have never come to them with such concerns. “I think you would have to be sleeping inside a lavender field from the minute you are born to experience any kind of tissue changes from lavender,” said Saskia Kleinert, founder and director of the Emeryville Health & Wellness Center. Kleinert, a former faculty member of the National Holistic Institute, uses essential oils to help her clients treat insomnia, weakened immune systems, and postpartum depression, among other ailments. “The parents of the children were excessively using products with fragrances in them,” agreed Jeanne Rose, a San Francisco-based herbologist and author who has been studying and teaching about herbs, aromatherapy, and oil distillation for over 50 years. “If it smells loud, it can’t be good.”

Kleinert and Rose said that it is likely synthetic fragrances in the products, which are widely considered to be carcinogenic, or contaminants that can enter the oil mixtures during production that are responsible for these cases.

To ensure family safety, both aromatherapists recommend that people carefully read product labels and avoid purchasing essential oils from multilevel marketing platforms. Instead, they say consumers should opt for companies that run purity and quality analyses. “We have two of the best essential oil manufacturers in the Bay Area — Eden Botanicals and Prima Fleur Botanicals — that make real products from real trees,” said Rose.

Korach and Diaz stated that the endocrinology community is currently reviewing a study that will evaluate chemical components of the oils to address contamination concerns. In the meantime, Diaz recommended that parents keep children away from products containing lavender and tea tree oils altogether. “Children’s exposure should be taken seriously,” he said. “There’s a reason why these two essential oils have been deemed ‘endocrine disrupting chemicals’ by members of the U.S. endocrine society.”

On why the essential oils have gained mainstream popularity, Diaz believes the phenomenon is a reaction to people’s frustration with traditional medical outlets. The incorporation of essential oils presents an attractive nuance to traditional health care industry, often accused of over-prescribing medications with potentially risky contraindications. As this trend continues, it’s important to remember that just because a product is natural does not mean it is safe for unfettered consumption. “I’ve had people come in with endocrine problems from compounds they use to try and lose weight that cause them to develop hypothyroidism; intoxications in people who have taken too much Vitamin D,” said Diaz. “Really, it’s best to do the thing that they say in the boring part of drug commercials: Talk to your doctor.”

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