Emerging Interest: The Case of Lavender Oil
by David Loughran
Lavender oil, a popular ingredient in many personal care products for both adults and children, is the latest addition to CoMeta’s inventory of emerging interest agents. Emerging interest is the earliest phase in the emerging risk life cycle when science first begins to investigate a hypothesis of injury. A 2007 study published in the New England Journal of Medicine first raised the possibility that regular use of lavender oil in personal care products could cause early breast growth in boys (prepubertal gynecomastia) and girls (premature thelarche). The case report study found that gynecomastia in three prepubertal boys coincided with the use of soaps and lotions containing lavender oil and moreover their gynecomastia resolved after discontinuing use of the products. The results of experiments with human cell lines reported in the same study indicated lavender oil can mimic the actions of estrogen, which stimulates breast growth in girls, and inhibits the effects of androgen, which prevents breast growth in boys.
Understandably, the 2007 NEJM study generated considerable controversy at the time. Lavender oil has been incorporated in personal care products for centuries and is the most widely used essential oil on the market today. Moreover, prior study showed lavender oil to be generally well-tolerated with no significant adverse effects.
Should parents discontinue using an essential oil with a beloved aroma and many purported beneficial effects (e.g., treating insomnia, anxiety, and depression) based on three case reports and a single in vitro study? Probably not, but studies conducted over the intervening 15 years have failed to rule out the possibility that lavender oil has endocrine disrupting properties. Three additional case report studies published in 2015, 2016, and 2019 report associations between prepubertal gynecomastia and premature thelarche and the use of personal care products containing lavender oil. The 2019 study published in the Journal of Clinical Endocrinology and Metabolism and funded by the National Institute of Environmental Health Sciences reported similar case study results to the 2007 NEJM study, but this time with premature thelarche, and provided additional supporting in vitro evidence that received considerable media attention at the 100th annual meeting of the Endocrine Society.
Even with supporting animal studies published in 2021 and 2022, though, lavender oil remains in the emerging interest phase. With a small literature base including some negative findings (see Politano et al (2013- animal) and Hawkins et al (2019-human)), CoMeta’s general causation risk scores for lavender oil and reproductive or breast injury are close to zero and are expected to increase by only 0.1 points over the next eight years.
Thus, as with all emerging interest agents, we do not recommend that casualty insurers invest in developing an underwriting strategy for lavender oil at this time. The science is insufficient to support bodily injury litigation and the pace of research over the past 15 years does not suggest the science will advance enough over our forecast window to justify specific underwriting action.
But we do recommend that underwriting management keep tabs on how lavender oil science is developing. Given the popularity of lavender oil and its use in products intended for children, the exposure is considerable and underwriting should be prepared to take action if the science shifts materially against expectations.