Researchers have found toxic metals — including arsenic and lead — in over a dozen popular brands of tampons, raising questions about a menstrual hygiene product used by millions of Americans.
Their study, published last week in the scientific journal Environment International, adds to a growing body of research about chemicals found in tampons but is believed to be the first to specifically measure metals.
The negative health effects of heavy metals are well-documented and wide-ranging, including damaging the cardiovascular, nervous and endocrine systems; damaging the liver, kidneys and brain; increasing the risk of dementia and cancer and harming maternal health and fetal development.
“Despite this large potential for public health concern, very little research has been done to measure chemicals in tampons,” lead author Jenni Shearston, a postdoctoral scholar at the UC Berkeley School of Public Health, said in a statement.
Shearston led a team of scientists from Columbia University and Michigan State University in examining 30 tampons from across 14 brands and 18 product lines, which they did not name in the study.
The sampling includes products of various absorbencies, listed as “top sellers” by a major online retailer and purchased both online and at stores in New York City, London and Athens between September 2022 and March 2023.
Researchers detected “measurable concentrations” of all 16 metals they were looking for in the tampons, as well as “elevated mean concentrations” of toxic metals including lead, arsenic and cadmium.
The study says there are several ways metals could get into tampons. Raw materials like cotton and rayon could be contaminated by water, air or soil during production, while metals may in some cases be added intentionally in the manufacturing process either for odor control, pigment or as an antibacterial agent.
The exact amount of metals varied among the tampons, based on which region they were purchased from, whether they were made of organic or non-organic material and on store- versus name-brands, according to the study.
“Lead concentrations were higher in non-organic tampons while arsenic was higher in organic tampons,” it added. “No category had consistently lower concentrations of all or most metals.”
Researchers say the study marks an important first step in confirming the presence of toxic metals in tampons, which are used by an estimated 52% to 86% of menstruating people in the U.S.
But it doesn’t give them enough information to definitively link the metals to negative health effects.
They say more studies are needed to determine to what extent such metals might “leach out of tampons” and into peoples’ bodies. They’re calling not only for more research, but also for stronger regulations.
“I really hope that manufacturers are required to test their products for metals, especially for toxic metals,” Shearston said. “It would be exciting to see the public call for this, or to ask for better labeling on tampons and other menstrual products.”
In the U.S., the Food and Drug Administration (FDA) classifies tampons as medical devices and regulates their safety. However, there is no requirement to test tampons for chemical contaminants, and the FDA only recommends that tampons not contain pesticide residue or dioxin.
FDA spokesperson Amanda Hils told NPR that “all studies have limitations,” pointing to the outstanding questions about whether metals are released from tampons and into the bloodstream. Nevertheless, she said the agency is reviewing the research.
“We plan to evaluate the study closely, and take any action warranted to safeguard the health of consumers who use these products,” Hils added.
“Some of these impurities are present in the environment or naturally present at much higher levels in common fruits and vegetables or even made by the human body,” it said, adding that its members use “rigorous criteria for quality and hygiene.”
People who menstruate may use more than 7,400 tampons over the course of their reproductive years, the study authors calculated, with each tampon staying in the vagina for several hours at a time.
Dr. Nathaniel DeNicola, an OB-GYN who served as the environmental health expert for the American College of Obstetricians and Gynecologists, says the more pressing question is not whether there are chemicals in tampons, but “when does it convert to a dangerous amount?”
Some of the metals found in the tampons — including copper, calcium, iron and zinc — are not only considered safe, but recommended for patients by many doctors, he notes. They would not be damaging in low amounts, but a cumulative amount could have a lasting effect on a person’s endocrine functions.
Trace amounts of arsenic, for example, are sometimes found in food and not considered to be toxic, but high amounts could be fatal. In contrast, as the study notes, “there is no safe exposure level” to lead.
It’s not clear from the study whether people are getting harmful amounts of each metal from tampons, DeNicola says.
“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 adds. “And it’s not to say that it’s nothing we should worry about. I mean, I don’t think most people hear that and think, ‘Oh, good, I’ve got more plastic in me.’ But we do have to recognize that small amounts of these chemicals are ubiquitous.”