You Don't Need To Worry About Pesticides In Your Tampons

The very problematic science behind some recent headlines.

Pictured: Bamboo tampons. Did you know that “bamboo” fibers like this are actually just rayon? Now you do. Photo by Maddi Bazzocco on Unsplash

For half of humanity, tampons are a basic necessity. Like toilet paper, they are a relatively modern solution to a problem that’s been irritating people for a very long time. They’re popular, with half of all women preferring tampons to other menstrual products, and around 80% using tampons as part of their routine.

And, according to recent headlines, they are dangerous. As reported by The Guardian and Women’s Health, tampons may have worryingly high levels of pesticides in them that could be poisoning you from the inside.

Pictured: Scary? Photo by Reproductive Health Supplies Coalition on Unsplash

Fortunately for the large proportion of people who’ve used tampons, this is ridiculous alarmism. In reality, the new data shows that pesticide levels are incredibly low in tampons, well below a rate that could cause any concerns.

The Data

The new data comes from a group called the Pesticides Action Network, or PAN. They are a charity from the UK whose aims include “eliminate hazardous pesticides” and “reduce dependence” on ALL pesticides by lobbying the government to take action.

Their new report is a fairly interesting piece of work. The main body of the report is 30 pages long, of which PAN spends 3 pages talking about their new data and 27 discussing other research and policy recommendations.

The actual data is very simple. PAN tested 15 boxes of tampons for glyphosate residues. Glyphosate is a herbicide that’s used quite a bit in farming, because it’s generally non-toxic and very effective, but there are some concerns that very high levels of exposure - say, for farm workers - could cause non-Hodgkin’s lymphoma. I’ve written about these worries before. The data is not very strong, but importantly it’s only a concern at all for people exposed to industrial levels of the herbicide. For regular people getting tiny amounts of the stuff, the data overwhelmingly shows no health problems.

The report from PAN is very light on their methodology. They don’t report which lab they used, what that lab did, how the samples were tested, what part of the tampons were tested, etc. This is problematic. For one thing, the majority of a tampon is not exposed to the vaginal mucosa - the lining of the vagina - so it’s very unlikely that anything could be absorbed from the inside of a tampon. If PAN tested the core sections of tampons, the results might not mean anything at all to the average tampon user.

The results are also straightforwardly reassuring. PAN found that the tampons they tested contained an average of 0.004mg/kg of glyphosate. That’s 4 parts per billion. They then did two things. Firstly, they compared this level of glyphosate with the drinking water standards for the UK and EU, which require drinking water to have 0.1 parts per billion of any individual pesticide or less.

This is absurd. Drinking water standards, as that link acknowledges, are set intentionally low because drinking water is in everything. You drink it. You put it in your food. You wash in it, and if you’re like my toddler you get it all over the floor regularly at bath time. You are exposed to it in thousands of ways, which means that we have to make limits on drinking water as conservative as possible to ensure people’s safety.

But tampons are a single-use item. You don’t eat them, and you absorb very little out of them generally. Indeed, they are specifically manufactured so that they absorb fluids very well without breaking down. It makes no sense to compare herbicide residues in tampons to drinking water limits.

The other thing that PAN did was use the methodology from a French government report to calculate the expected daily exposure to glyphosate that a person could expect from using these tampons. The formula for this is very simple:

For their worst-case scenario, ANSES - the French government agency - assumed that T and Abs were equal to 100%, so PAN did as well. This essentially simplifies the equation to:

DED = Total substance in product per day/Body weight.

ANSES acknowledges in their report that this is a bit absurd. The assumption here is that someone is absorbing 100% of the herbicide or other substance from a tampon, which is physiologically impossible. Tampons, remember, don’t break down, so there is no way for the majority of any individual chemical to leach from the product into your body.

However, based on this worst-case scenario, PAN came to the conclusion that a teenager using the tampons they sampled would be exposed to 0.004(glyphosate per kg in tampons)*0.006(total weight per tampon)*6(tampons per day)/30kg(5th percentile of weight for a teen in the EU) = 0.0000048mg/kg/day. The current safe limit for glyphosate exposure as set by the EU and noted by ANSES, is 1mg/kg/day, so this is around 200,000 times below the level that could be considered harmful.

In other words, entirely safe. So why are there headlines saying that you should be worried about toxic chemicals in your tampons?

Well, after finding these extremely low levels of glyphosate in tampons, PAN said this:

“Questions must be raised about this methodology that calls [these levels] safe”.

They then go on a bizarre rant. I’m just going to copy+paste the whole thing here for you to read.

The rant continues on the following page, but it doesn’t get any more scientific.

The argument is that the ANSES report - and this WHO document that it is originally drawn from - are only concerned with the oral exposure and not vaginal. Because vaginas may absorb more glyphosate than your ears or abdomen, the number may be wrong.

This is incorrect in many ways. The WHO document does indeed use an oral exposure route, but they state that there are no problems with a total level of exposure in either rats or mice even at 200mg/kg/day. The 1mg/kg/day estimate is a very low safety threshold set over a hundred times below what appears to be safe for rodents. Even if vaginal absorption was double oral, which is what the 1983 paper looking at 4 women that PAN references implies, it would still not really change this equation very much. The safe limit would be 0.5mg/kg/day vaginally, or around 10,000 times higher than the amount PAN found in tampons.

In addition, this discussion is entirely meaningless because the PAN and ANSES methodology already assumes that 100% of the glyphosate is absorbed. This is wildly unlikely, but that’s the assumption of their calculations - in the worst-case scenario, they are assuming that every single milligram of glyphosate present in tampons is somehow absorbed into the body.

What the PAN report shows is that even if vaginas could dissolve tampons like a pool of acid in a bad cartoon, AND that the body then absorbs all of the tampon, the amount of glyphosate in the products is negligible. There is more glyphosate in the water you drink each day than the tampons you use, so even in a worst-case scenario where you are absorbing entire tampons into your body you still wouldn’t have to worry about glyphosate exposure (you might have some other concerns though).

Policy Problems?

The one thing that PAN does somehow manage to get right is that there is currently a bit of a policy black hole here. Tampons are an essential product for a large portion of the world’s population, but there are few programs dedicated to testing them for possible issues. Glyphosate isn’t a problem, but it’s plausible that there are other environmental risks that we simply don’t know about.

It’s not absurd to say that countries such as the UK should start testing tampons for possible environmental contaminants. I would not be surprised if such testing uncovered an issue or two, because a lot of the world’s cotton is grown in places with relatively lax standards for environmental pollution.

That being said, the recent report is incredibly misleading. The newest data shows, if anything, that tampons are safe. You don’t have to worry about being poisoned by a tampon next time you have your period.