Some women are turning to menstrual cups after a study found toxic metals in tampons. Here’s what period cups are and how they work

After all, between 52% and 85% of people with periods in the United States use tampons, according to the July 12 study, conducted by the University of California Berkeley School of Public Health and published in the journal Environmental International. 

It found that, in 30 tampons from 14 brands and 18 product lines (all unnamed, unfortunately) there were traces of 16 heavy metals—including some considered toxic—likely due to heavy metal contamination of soil in the agricultural industry. Researchers found that non-organic tampons had the highest concentration of lead, and that organic tampons had the highest amounts of arsenic.

Many experts, including Instagram star Dr. Jennifer Lincoln, have said there’s no reason for panic—pointing out not only that levels of metals found were extremely small (and that we’re exposed to higher amounts in certain food products and bottled water) but that more research is needed to find out how much of the metal is actually absorbed into your body.

Still, that doesn’t mean some women aren’t feeling worried and looking for alternatives—especially considering that there’s already been indication of PFAS, or “forever chemicals,” found in some sanitary pads, tampons, and period underwear, according to studies by Mamavation and the American Chemical Society. 

Enter: reusable menstrual cups and discs.

What are menstrual cups and are they safe?

Used by only 19% of those who menstruate, and mostly by those in their 20s and 30s, according to 2023 findings of the Harvard T.H. Chan School of Public Health, menstrual cups are reusable tampon alternatives that collect blood rather than absorb it. Most are made from medical-grade silicone—a synthetic polymer made of silicon, hydrogen, carbon, and oxygen—that’s been tested and approved by the FDA for being non-toxic and non-reactive with human tissue.

They are inserted by folding and pushing up against the cervix, where it creates a seal. Discs work the same way but are shaped differently, like wider, circular bowls.

Dr. Olivia Manayan, an OB/GYN based in Hawaii, points to a 2019 meta-analysis published in the Lancet that notes, “Our review indicates that menstrual cups are a safe option for menstruation management and are being used internationally,” and also highlights the pros and cons. In addition to being reusable and cost-efficient, the study finds there is not more leakage than with tampons and may actually be less—and that there is a lower risk of toxic shock syndrome with cups than with tampons. A con, Manayan points out, is that there is a higher rate of IUD dislodgment (though it’s likely from being placed to high in the vagina) and a risk (though rare) of an allergic reaction to the silicone.

Kim Rosas is a self-taught menstrual cup expert who started using the items over 12 years ago for environmental reasons—the same reason she used cloth diapers for her kids just before that. “I became a convert more because they were comfortable and convenient, and that’s sort of been my advocacy point for helping people switch,” Rosas tells Fortune.

In 2020 she founded Period Nirvana to help educate the public, including with a quiz that helps you choose your best option (also offered by a similar site, Put a Cup In It), and to offer a range of different cups and discs for sale. She says she’s seen her online sales double since the tampon study’s release. 

“But there’s a lot of other reasons to switch besides that,” Rosas stresses. Topping the list for her, in addition to comfort and convenience, is that the reusable products, which cost between $30 and $40 each, will save you money.

“They last for up to 10 years. And you get your money back within about one to three months,” she says. 

What are some concerns about using menstrual cups?

The biggest questions Rosas gets, she says, are: “How’s that gonna fit?” and “What do I do in public?”

Regarding public anxiety—it’s true that once the cup is full, you’ll need to remove it, dump the blood into a toilet, and then wash both the cup and your hands. And the thought of a Carrie-like scene in a school, work, or public restroom obviously gives many women pause. But Rosas says it doesn’t need to be an issue.

“I like to let people know it depends on your flow,” she says. If you have a heavy period and are concerned about overflow and leakage, then yes, you’ll need to plan ahead for emptying and washing in the middle of the day. But you can empty the cup or disk and reinsert it and wash it later—plus there are “really handy cup wipes,” she says, and at least one brand, Saalt, that makes a travel kit with a tiny squirt bottle for in-stall, over-toilet cleansing.

But if you have more of an average or light flow, she says, “you can go the entire day without even needing to address it. You have up to 12 hours to wear [a cup] safely. So unless you’re worried about overflowing, you can actually just wait until you get home to empty it and wash it.”

As for how it will fit, she says she just reminds people of the many things that can fit in a vagina, from a penis to a full-term baby.

Carol Queen, staff sexologist for the legendary San Francisco sex-toy shop Good Vibrations, explains that the vagina “naturally expands during arousal, and, of course, childbirth, for those who have that experience. The vagina is designed to accommodate items as small as a finger or tampon and larger ones like toys or penises, and then return to its ‘resting size,’ which is comparable to a lightly closed fist.”

Other women may fear “losing” the cup or disc inside their bodies. But, reassures Queen, “They won’t. The vagina is essentially a closed organ, like a cul-de-sac, with the exception of the very small os [opening of the] cervix. For those who are afraid of harm: Wash your hands first, don’t be rough with insertion, use a little bit of lubricant if it helps.”

Still others may be uncomfortable with the idea of having to touch their genitals so much—possibly, Queens says, due to lingering myths and fears we’ve been taught: the notion that menstrual blood is dirty; the idea that touching the vulva/vagina will cause illness; the belief that the vulva/vagina are inherently sexual and any contact with them is, too; the idea that inserting anything into the vagina causes or hastens virginity loss; and, finally, the idea that inserting anything into the vagina will be painful. 

For those who are afraid that they are going to alter themselves sexually somehow, she adds: “Inserting a tampon or menstrual cup is not a sexual act. It does not change the vagina sexually.”

The best way to figure out the best brand and size for your body, Rosas advises, is by first checking to see if you have a low or high cervix—inserting your finger into your vagina, maybe while in the shower, until you reach your cervix, which feels like the soft tip of a nose. Make a mental note of where on your finger you stop and then measure that length with a tape measure. 

“I would encourage trying a few on to see which works best for you,” says Manayan, who adds that, depending on your daily activities, you may require different kinds. “For instance, if you are doing a lot of physical activity, a more rigid cup may better serve you.” And, she says, “For people who are used to using tampons, note … that the menstrual cup is meant to sit lower in the vagina than a tampon typically does; this may take a little getting used to.”