No, a study didn’t establish that tampons are toxic and cause health problems, contrary to social media posts

In July 2024, news reports of a study reporting the presence of heavy metals in tampons triggered a wave of fear and concern on social media. TikTok videos, which received tens of thousands of views, cited the study as evidence that tampons are toxic.

We also found posts on Threads claiming that the study found “high” amounts of heavy metals in tampons (examples here and here) and linked this to reproductive health problems like polycystic ovary syndrome (PCOS), endometriosis, infertility, and miscarriage.

This isn’t the first time that tampons have become the subject of a health scare. In 2022, a viral TikTok video claimed titanium dioxide in tampons causes reproductive cancers. Science Feedback explained that this claim was unsubstantiated by scientific evidence in this Insight article. The claim was also debunked by AFP Fact Check and PolitiFact.

As with the claim about titanium dioxide, the claim that heavy metals in tampons poison women and cause health problems is unfounded. We explain more below.

What did the study do?

A study published online in June 2024, and led by researchers at the University of California Berkeley and Columbia University, measured the level of 16 metals in tampons, including lead and arsenic^[1].

The researchers hypothesized that tampons could be a source of heavy metal exposure since tampons contain cotton, and cotton plants absorb metals from soil. The metals in soil can be naturally occurring or the result of human activity, such as using fertilizers and pesticides. Metals can also be added during tampon production to reduce microbial growth and odor.

The researchers tested 30 tampons from 14 brands, most of which came from the U.S., while a few came from the European Union or the U.K. To extract the metals from the tampons, the researchers dissolved them in nitric acid at roughly 82 degrees Celsius. They then used a technique called mass spectrometry to measure the amount of each metal in the samples.

They found detectable levels of all the metals tested, including lead and arsenic. The average amount of arsenic detected was 2.56 nanograms per gram (ng/g) of tampon; for lead, it was 120 ng/g. A nanogram is one-billionth of a gram.

The highest level of arsenic detected was 14.1 ng/g; for lead, it was 468 ng/g. For context, a regular tampon weighs about one gram, while a super tampon, which absorbs more menstrual blood, weighs about two grams.

They also found differences in the types of metal present depending on whether the tampon was organic or non-organic. There was more lead in non-organic tampons compared to organic tampons, but more arsenic in organic tampons compared to non-organic tampons.

Because lead and arsenic are both known human toxins—and there’s no safe level of exposure to lead—the researchers called for stricter regulation of tampons that ensure manufacturers test tampons for chemicals. However, the authors acknowledged that their study “does not provide information about potential bio-accessibility of tampon metals and thus we cannot estimate health risks (if any) from tampon use”.

Study didn’t determine whether metals leach out of tampons; tea and rice also contain metals

Science Feedback reached out to the study’s corresponding author, Jenni Shearston, a postdoctoral scholar at the University of California Berkeley and an environmental epidemiologist, about the credibility of the social media claims.

In an email, Shearston wrote that “we do not have evidence for this claim [that tampons are toxic and cause reproductive health problems] at this time”.

She emphasized that the study “did not evaluate if tampons are responsible for reproductive health problems” and “does not show if the metals can come out of the tampons, or if they can be absorbed into the body”.

Speaking to CNN, Kathrin Schilling, a senior author of the study and an assistant professor of environmental health sciences at Columbia University, clarified that “I do not want people to panic, but to be aware that heavy metals have been found in these menstrual products”. She added that “the next step is to do research that would show if the metals leach from the tampon into the body”.

In the same report, Anna Pollack, an associate professor at George Mason University who studies how environmental chemical exposure affects reproductive health, said that metals in tampons could pose a “significant problem” if they leached from the tampons into the body. But at this time, she considered that there was “no reason for people to be afraid to use menstrual products”.

This question was also raised by Nathaniel DeNicola, an obstetrician and gynecologist and an environmental health expert for the International Federation of Gynecology and Obstetrics, who told NPR that the more relevant question is whether people are getting harmful amounts of metals from tampons.

“When you start to look at the kind of chemicals that are found in our human system, the reality is that in modern life, we’re kind of swimming in them,” he said. “And it’s not to say that it’s nothing we should worry about […] But we do have to recognize that small amounts of these chemicals are ubiquitous”.

A Substack article penned by obstetrician and gynecologist Jen Gunter looked at this in greater detail, comparing the amount of lead and arsenic that the study found in tampons with those found in tea, the latter based on figures from a 2013 study.

She found that the amount of lead in 200 milliliters (mL) of green tea (322 ng) was about a third higher than the amount found in a super tampon (240 ng). Arsenic was about 12 times higher in the same amount of green tea (62 ng) compared to a super tampon (5.12 ng). In brief, the relative amounts of lead and arsenic entering the body would be considerably higher from a cup of green tea, even when we assume all the metal content in a tampon is absorbed by the body—again, something that wasn’t demonstrated in the study.

Moreover, these levels in tampons and green tea are much lower than the U.S. Environmental Protection Agency (EPA)’s limits for lead (5 parts per billion or 5,000 ng/L) and arsenic (10 parts per billion or 10,000 ng/L) for bottled water. The European Union also uses the same limits for drinking water.

Based on this, “a human could never use enough tampons in a day to get anywhere near the amount of arsenic or cadmium the EPA allows in a single bottle of water”, Gunter concluded.

A 2015 report from the U.K.’s Food Standards Agency (FSA) also supports findings of lead in tea, although the levels it found were lower than those detected in the 2013 study cited by Gunter. Half the tested samples showed lead levels below the detection limit of the test, which was 200 ng/L, although two samples showed lead levels greater than 1,000 ng/L. Overall, the agency considered the amount of lead in the 51 samples of brewed teas tested to be “very low”.

As for arsenic, it’s recognized as a contaminant of concern in rice and limits have been established to safeguard consumer health. For example, the European Commission (EC) has set a maximum level of inorganic arsenic permitted in white rice at 150 micrograms per kilogram of rice (or 150,000 ng/kg). One standard serving of rice for adults is a half-cup of cooked rice. According to the U.S. Department of Agriculture, the weight of one U.S. cup of cooked rice is 158 g, meaning a half-cup of cooked rice weighs approximately 80 g.

If we apply the EC limit, this translates to a maximum limit of 12,000 ng of arsenic per adult serving of rice, which outstrips the amount of arsenic detected in the tampon study by more than 2,000 times.

In a Substack article, Andrea Love, a biomedical scientist and science communicator, questioned whether the methods in the study were representative of conditions in the human body. In order to extract the metals from the tampons, the researchers subjected the tampons to 70% nitric acid and a temperature of about 82 degrees Celsius.

“I think everyone can agree, those are not the conditions inside a vagina,” she wrote, adding that the amount of metals extracted with this method is unlikely to represent the amount of metals that would leach out of a tampon in use. “Detection does NOT equal relevance,” she cautioned.

In her email to Science Feedback, Shearston responded to this criticism, explaining that the goal of their study wasn’t to mimic the conditions of the vagina, and that the researchers needed to first measure the amount of metals in the tampons before conducting follow-up leaching experiments that replicate conditions in the vagina.

“This gives us an idea of the amount of variability and range of the concentrations we will look for in leaching experiments,” she wrote, adding that their team “is conducting leaching experiments in conditions that more closely resemble the vagina right now”.

Gunter didn’t consider the study’s findings to be “panic-worthy”, but like the authors, she called for the U.S. Food and Drug Administration (FDA) to strengthen regulations on tampons. This would provide standards—like those that already exist for water—that enable people to understand their cumulative risks from metals that are present in multiple sources. Moreover, stronger regulations would reduce health scares related to menstrual products. She explained:

“Every year, some new menstrual product concern that probably isn’t an actual concern causes people to get scared, and then a subsequent rogue’s gallery of social media influencers and Big Natural profiteers turns that panic into attention, clicks, and profit. They are able to do this because the rules around tampons with the FDA are rather lax.”

Conclusion

Lead and arsenic are naturally occurring and ubiquitous in the environment. As such, they are impossible to avoid completely. In fact, both can be found in common foodstuffs like tea and rice.

While a study did find heavy metals like lead and arsenic in tampons, it didn’t look at whether people absorbed harmful amounts from using tampons. It also didn’t determine whether heavy metals in tampons are associated with reproductive health problems like endometriosis and infertility. Moreover, the levels detected in the study can be smaller than other sources that we’re exposed to, like tea. Therefore, social media posts citing the study as evidence that tampons are toxic exaggerate the weight of the findings.

UPDATE (19 July 2024):

We updated the review to include a reply by the study’s first author, Jenni Shearston, regarding the credibility of the social media claim and criticism of the study. These comments were added to paragraphs 12 to 14, and to paragraphs 28 and 29.

REFERENCES

• 1 – Shearston et al. (2024) Tampons as a source of exposure to metal(loid)s. Environment International.