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July 11, 2024

Ask the expert: Metals found in tampons — what it means for users

Kristen Upson
Kristen Upson, assistant professor in the Department of Epidemiology and Biostatistics at the MSU College of Human Medicine. Courtesy photo.

New research from Kristen Upson and colleagues, published in the journal Environment International, found 16 metals in 30 tampons representing 14 different tampon brands.

Upson, assistant professor in the Department of Epidemiology and Biostatistics at the Michigan State University College of Human Medicine, says she was surprised that several toxic metals were detected in all the tampons tested, including lead, cadmium and arsenic.

Upson is an NIH-funded researcher who leads the research group, Period Go Me!, the program on environmental risk factors in our daily lives, gynecologic outcomes and menstrual equity, which is focused on research at the intersection of gynecologic health and environmental health. Here, she explains the study’s findings and outlines plans for ongoing research.

What made you think there might be metals in tampons?

As we were looking at previous studies, we realized that tampons had been tested for several different chemicals, but not metals. The absorbent core of tampons is made of plant-based material, like cotton, rayon or a mixture of both. Plants are often exposed to metals, so we thought this could be important.

What did you find?

Testing was done by the senior author on the paper, Kathrin Schilling, a laboratory expert in metals at Columbia University Mailman School of Public Health. We purposefully selected tampons that are commonly purchased in the United States — either online or in brick-and-mortar stores.

Metals of some kind, including toxic metals like lead, arsenic and cadmium, were present in all the tampons that we tested, regardless of brand. That is to say, name brand, store brand, organic and nonorganic tampons all had metals that were detected. And while the concentrations of some metals were low, we have to remember that there are no safe levels of exposure to toxic metals, including lead.

Going into this research, I was curious to see if there would be a tampon product that was consistently lower in metal content. However, we found metal concentrations across the board in all the tampons we tested.

Why could this be a problem?

This could be a problem for at least two reasons. First, tampons are used in the vagina, which allows more absorption than the skin, or dermal layer, on the outside of your body. Not only is the vaginal wall permeable and highly vascularized, chemicals that are absorbed can bypass liver metabolism and directly enter systemic circulation. When we think about tampons, a product used over decades for hours at a time several days each month, we need to consider the potential exposure to chemicals that are in the product.

Second, toxic metals, like lead, cadmium and arsenic, are associated with adverse health in humans. Lead is problematic because it mimics calcium found throughout the body including in bones, the heart and the brain. As a result, when we’re exposed to lead, it can negatively affect essentially every organ system. Cadmium and arsenic also can affect several different organ systems, with arsenic being a known carcinogen.

That said, our study measured metals in tampons, but we did not look at whether menstruators who use tampons are exposed to the metals detected. There are lots of things to consider when tampons are used, including how tampons interact with menstrual fluid and the vaginal environment like temperature and pH.

Could metals found in tampons be absorbed into the body? That’s the question for our next study.

Where are these metals coming from?

There are several possibilities. The plant material in tampons could be exposed to metals during the growing process — air, soil and water can all be contaminated and could transfer metals. Perhaps metals are introduced during the manufacturing process or maybe metals were added to give the tampons unique qualities that are important to their functionality. For example, metals could have been added for antimicrobial purposes, odor control, lubrication for smooth insertion, or to help prevent leakage. Interestingly, although we detected metals, they were not listed on the tampon product ingredient list.

How many people could this affect?

Millions, potentially. In general, these findings could affect half of the human population who have or will experience menstrual periods. Between 52% and 86% of people who menstruate in the United States use tampons. Considering the number of years between when a person first has a menstrual period and enters menopause, the number of tampons could be upwards of 7,000 to 10,000 tampons during a person’s lifetime.

What should happen next?

Although these findings are eye-opening, based on our study alone, we cannot make any recommendations about tampon use. Tampons remain an important option for managing menstrual periods. That said, this study really points to the importance of measuring the levels of metals or chemicals in everyday products.

Since our study showed that metals are present in the tampons we tested, what we as researchers need to do now is learn more about whether those who use tampons are actually exposed to the metals detected.

Bottom line: We need more research to figure this all out. We’re working hard on this front and writing grants to get the funding to take the next steps.

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