There is no evidence that heavy metals in tampons cause endometriosis, PCOS, or cancer

The context

A recent study by researchers at UC Berkeley found traces of heavy metals, including lead and arsenic, in over a dozen different brands of tampons sold in the U.S., U.K., and EU. 

These findings have caused anger on social media over the health implications it could have on tampon users, which in the U.S. alone amounts to an estimated 52-86 percent of all menstruating people. Since the vaginal and vulvar tissue is highly permeable, chemicals absorbed vaginally could directly enter the bloodstream without undergoing metabolism and detoxification in the liver. 

"So you just found out that you've been sticking a lead and arsenic-soaked popsicle up your vagina for years, decades maybe," one content creator says in a viral TikTok video with over 660,000 views and 77,000 likes. 

She goes on to suggest that this is linked to endometriosis, polycystic ovarian syndrome (PCOS), ovarian cysts, infertility, hormonal imbalance, and cancer in the reproductive system – and speculates that it could be a deliberate attempt to keep women weak.

However, this is unsubstantiated, as the research didn't focus on the exposure and health implications of heavy metals in tampons – only their mere presence.

The facts

Toxic metals like arsenic and lead have been known to cause a range of adverse health effects in humans. Inorganic arsenic is carcinogenic to humans, and lead exposure, which is harmful to almost every organ, is known to cause reproductive health issues in adults. Additionally, some studies link lead exposure to an increased risk of PCOS, infertility, ovarian malfunction, and endometriosis.

That being said, this new study is the first to examine heavy metals found in tampons – and crucially, it did not analyze whether the metals can leach out of the tampons and be absorbed by the body in quantities large enough to have a negative health impact. 

Due to this, one of the study's senior authors has warned people against panicking, and the next step is to research the possible exposure.

Dr. Jenni A. Shearston, a postdoctoral scholar at the UC Berkeley School of Public Health and UC Berkeley's Department of Environmental Science and lead author of the study, told Logically Facts that previous studies have found that arsenic and lead have been associated with endometriosis, PCOS, and fertility issues, but it is not known whether the presence of these metals in tampons is contributing to any of these diseases.

"We do not know if the concentrations of the metals we found in tampons are dangerous to health. First, we need to see how much of the metals we found can come out of tampons and be absorbed through the vagina into the body. Once we know this amount, we could determine whether they are dangerous," Shearston said.

She highlighted that the body does absorb at least one toxin from tampons, the one that causes the rare, life-threatening bacterial infection known as toxic shock syndrome, but that there are no studies that describe metal absorption through the vagina.

The study found that tampons contained an average of 2 nanograms per gram of arsenic and 120 nanograms per gram of lead. While these are small concentrations, lower than the U.S. limits for soil and drinking water exposure, one of the paper's main authors emphasized to the online health resource Verywell Health that they could pose an issue if accumulated in the body. The average menstruator uses between 10,000 and 12,000 menstrual products over their reproductive life, which is around five years of cumulative exposure. 

On the contrary, other experts have criticized the study and its media coverage for being alarmist. Gynecologist and author Dr. Jen Gunter pointed out in a Substack post that the average lead and arsenic levels found in one tampon are lower than those in a cup of organic green tea. Similarly, the microbiologist Dr. Andrea Love wrote for the science advocacy group the Genetic Literacy Project that the European Union's safety threshold for lead in foodstuffs is over 42 times higher than the average lead levels found in tampons. Both researchers also highlighted that the study extracted the metals by using 70 percent nitric acid, which is 2,000 times more acidic than a vagina, combined with 180C heat for an hour – rather than mimicking the physiological conditions of a vagina. This makes it difficult to know whether the metals would be released in the vagina.

Previous research has not given reason to suspect tampons as a source of exposure to dangerous levels of heavy metals. One study that analyzed blood concentrations of several metals following tampon usage did not find traces of lead and arsenic, only weak associations of zink and copper and a positive association of chromium. Another study, looking specifically at blood concentrations of mercury, found non-significantly higher mean levels among tampon users than non-tampon users but concluded that the results were not statistically significant.

The issue of harmful substances in tampons has been raised before, as earlier research has found harmful chemicals such as dioxins, a known carcinogen, in tampons. However, experts speaking to ABC News believe the current exposure levels are too small to pose a health risk. Similarly, the U.S. Food and Drug Administration's (FDA) risk assessment is that the dioxin exposure from tampons is "many times less" than normally present in the body from other sources and so small that the health risk is negligible.

Studies on the specific relationship between tampon usage and endometriosis haven't come back positive either, leading gynecology experts speaking to USA Today to conclude that there is no evidence that tampons are associated with an increased risk of endometriosis. Similarly, Dr. Gunter pointed out that tampons have not been associated with cervical cancer, either.

The verdict

Lead exposure is linked to reproductive issues, and arsenic exposure is linked to cancer. 

Low levels of both have been found in tampons. However, there is currently no evidence that these metals leach out of the tampons and are absorbed into the bloodstream, with the study's authors concluding that further research is needed. Therefore, there is no evidence to support the viral TikTok claim that tampon use is causing endometriosis, PCOS, infertility, reproductive cancer, and ovarian cysts, and we have therefore rated it as false.