How true is it that lavender and tea tree oil are endocrine disruptors?

Perhaps your question was prompted by this:

Chemicals in lavender and tea tree oil appear to be hormone disruptors

Lavender and tea tree oil have been being researched as potential endocrine disruptors for many years.

This study, a review of a series of cases from 2007, seemed to be one of the early ones to raise this concern:

Prepubertal Gynecomastia Linked to Lavender and Tea Tree Oils | NEJM

It was followed in 2008 by a rebuttal its findings:

Neither lavender oil nor tea tree oil can be linked to breast growth in young boys

There isn’t very much research yet on the endocrine disrupting effects of either lavender or tea tree oils which is why the 2018 press release says they “appear” to disrupt hormones.

The press release used overtly negative language to heighten the drama around findings which would otherwise be mildly concerning.

The constituents that are likely to have endocrine disrupting effects (eucalyptol, 4-terpineol, dipentene/limonene, alpha-terpineol, linalyl acetate, linalool, alpha-terpinene and gamma-terpinene) displayed varying degrees of impact on cancer cells in petri dishes.

Small in vitro studies that look at cells do not provide the same quality of evidence as large population based studies of actual human beings.

Many of the products people use contain endocrine-disrupting substances. This is a legitimate cause for concern because these hormonal effects can have wide-ranging consequences, including impaired fertility.

Endocrine disruptors may be found in many everyday products– including plastic bottles, metal food cans, detergents, flame retardants, food, toys, cosmetics, and pesticides. [1]

“How true” is an important way to ask about the truth of these findings.

There is truth that is binary: something is true or not true in a limited, factual way.

There is also truth that is context dependent, a larger truth that takes the fact and puts it into perspective according to its significance.

The binary truth of this situation is that lavender and tea tree probably do have some (limited) ability to affect hormones in some people (pubertal boys).

The larger contextual truth is that the effects of these volatile oils are less of an issue than our total exposure to endocrine disruptors, especially substances like BPA[2], which are used on a widespread basis.

Footnotes