[scythe]

The dose from aromatherapy ought to be much lower than that from topical or oral exposure. Several studies mention gynecomastia after rubbing lavender oil on the skin or drinking tea:

https://scholar.google.com/scholar?start=20&q=lavender+antia...

but merely smelling it should be a much smaller exposure. Disclaimer: I am not a doctor, I just like to read a lot.

[nate_meurer]

Only one of the reports in your search results purports to show gynecomastia in vivo. That's the report I mentioned in my earlier comment, and it's possibly the poorest quality "study" that I see cited with any regularity. Sample size of three, no controls, no blinding, no analysis of the products used. It's functionally equivalent to an old wive's tale.

The authors try to bolster their credibility by including some in-vitro evidence of estrogenic activity, which is extra-credit bullshit because there are plenty of common (and natural) substances that can disrupt hormones in a test tube, but show no such ability in actual humans. This is cheap research that the authors sensationalized with three completely uncontrolled and unblinded anecdotes. It blows my mind that this thing got published.

Notice how many other studies in your list cite that the Henley report. Also notice how many more recent studies list the same authors, namely Henley and Korach. Given the poor quality of their work and the overall implausibility of the proposed effect in vivo, I'd recommend taking their reports with a large amount of salt, at least until actual in-vivo effects are demonstrated in a higher quality study.

[scythe]

>That's the report I mentioned in my earlier comment, and it's possibly the poorest quality "study" that I see cited with any regularity. Sample size of three, no controls, no blinding, no analysis of the products used. It's functionally equivalent to an old wive's tale.

Case studies are widely used in medicine. But thanks for the downvote.

>Notice how many other studies in your list cite that the Henley report.

Here is a different report (early puberty in a girl):

https://www.pediatricnursing.org/article/S0882-5963(16)00076...

>Given the poor quality of their work and the overall implausibility of the proposed effect in vivo, I'd recommend taking their reports with a large amount of salt, at least until actual in-vivo effects are demonstrated in a higher quality study.

The cautious option is to avoid systemic use of lavender in populations where xenoestrogenic activity may be undesirable. Particularly in light of the fact that the “refutation” you linked was written by someone with an obvious conflict of interest.

[nate_meurer]

> Case studies are widely used in medicine. But thanks for the downvote.

Why are you saying I downvoted you? I'm not trying to be adversarial, just trying to provide counterpoints to what I believe is poor-quality reporting. Case studies are indeed often used in research. However in this situation we have an n=3 sampling without even a semblance of scientific control or analysis. They apparently didn't even bother to confirm whether the products that the kids were using actually contained lavender, much less characterize the quantity or composition. This isn't scientific by any stretch of the imagination. It's pure anecdote. It's no better than a facebook rumor.

> Here is a different report (early puberty in a girl)

Okay, another single case report, and again no analysis of the product being used, and no analysis of the "other CAM remedies" that the mother was reportedly using, nor any attempt to isolate other coincident changes in diet, treatment, chemical exposure, etc. Not sure how this helps anything.

> The cautious option is to avoid systemic use of lavender in populations where xenoestrogenic activity may be undesirable.

I disagree. You are of course free to be as cautious as you like, but IMO it's a paranoia that isn't justified by the research we've seen so far.

And as I said, the whole thing doen't really make sense. If we really do have to worry about lavender, then we're pretty fucked, because the chemicals of interest (such as the eight studied in the report you cited) are everywhere. Eucalyptus, basil, coriander, pine oil, mints of all kinds, citrus of all kinds... all of these and many more contain estrogenic terpenes in quantities similar to (or greater than) lavender. Are you going to be cautious of these as well if someone starts a rumor that they can disrupt your hormones?

> Particularly in light of the fact that the “refutation” you linked was written by someone with an obvious conflict of interest.

Tisserand's monetary interest in the industry could well lead to a conflict of interest. I don't know anything about him, but I'll grant that. But be careful about discounting him out of hand; it's easy to cross over into ad-hominem attacks. That he may have a dog in this fight doesn't necessarily make him wrong, and it doesn't make Henley's report more legit. Do you have a specific quarrel with Tisserand's reasoning? Do you have a rebuttal to his rebuttal, so to speak?

[Raphmedia]

> it's possibly the poorest quality "study"

Agreed and that's why I said there's a "fear" about it and not a "scientific fact".

[Raphmedia]

I wonder if topical application of lavender oil could help in the case of MTF hormone replacement therapy.

The articles say that it doesn't increase serum estrogen levels but I wonder if it might help the skin to achieve more "female" properties.