Comment by nate_meurer | Hacker News Reader

Comment by nate_meurer | Hacker News Reader

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AFAIK there is not yet any evidence showing hormone disruption from lavender in people. There is some recent research showing effects in vitro (including the report you cited), but nothing in actual humans.

The hypothesis is highly questionable to begin with, simply because the chemicals in lavender that show hormone disruption in vitro (almost all of them terpenes in the latest studies) are ubiquitous in nature, being present in hundreds of other widely consumed foods and herbs, often in high concentrations. Nature has surrounded us with these chemicals, and we've evolved in their presence. It would be really odd for lavender to cause problems, and not any of the other plants that contain the same substances.

The 2007 report (by Henley et al) that kicked off the whole panic over lavender and tea tree oil is a textbook case of poor quality pseudo-research that should never have been published. It had a sample size of three. That's right, three. It was neither blinded nor controlled in any way. It was simply a doctor who thought he noticed a decrease in gynecomastia among three kids after they stopped using some products that might have contained lavender or tea tree oil. If you want to know what's wrong with scientific publishing and reporting nowadays, reading about this case is a great place to start [1].

1 - https://roberttisserand.com/2013/02/lavender-oil-is-not-estr...

Does the 2013 rebuttal study in that link tell us anything about the safety of ingesting lavender extract (e.g. like the Silexan studies given above)? Wouldn't that involve much higher absorption than topical application?

Update: OK, weirdly enough, Tisserand seems to be highly involved in the aromatherapy industry per their own website, and the study [0] seems to involve researchers from the "Research Institute for Fragrance Materials" which sounds suspiciously like an industry-related group - is this reputable at all??

[0] http://journals.sagepub.com/doi/abs/10.1177/1091581812472209

I think this is one of those situations where most of the people who care enough to debate are those with an economic interest. Like perfumers. Conflict of interest is possible I suppose, but Tisserand's rebuttal seems well reasoned regardless, and he provides a list of other rebuttals from other people.

> Does the 2013 rebuttal study in that link tell us anything about the safety of ingesting lavender extract?

No, only topical application, albeit in far greater quantities than is seen in typical usage.

> Wouldn't that involve much higher absorption than topical application?

No, not necessarily. Silexan is delivered in 80mg doses. Higher levels of the same chemicals can easily be delivered by common foods. For example, a dish that's well seasoned with thyme or coriander can easily contain far more than 80 mg of linalool, and a few other ingredients would easily provide the same terpenoid profile as found in lavender, just as if you were to eat a large amount of lavender oil. Lavender really isn't anything special.

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