Two Stanford athletes say they designed a better tampon

Jan 18, 2024

Greta Meyer (left) and Amanda Calabrese, co-founders of Sequel, hold Sequel tampon pillows. The company promises a more efficient tampon.

When Greta Meyer and Amanda Calabrese were college athletes, they and their teammates always worried about leaks when they had their periods.

"My teammates were always like, ‘Can you check me?’ " Meyer said, noting that Stanford's lacrosse home-team uniform is a "bright crisp white." Calabrese competed on the U.S. Lifesaving team.

The women, both Stanford product-design majors and both now age 25, realized that high-level athletes needed better period protection, as did lots of others.

For a senior capstone project, they focused on this issue. First, they interviewed hundreds of women, discovering that the vast majority used tampons but didn't always trust them, necessitating back-up solutions like pads or period underwear.

"Our mechanical engineering brain came on, and we said, ‘Why are tampons failing?’ " Meyer said. They realized that often a used tampon had just one red stripe down the side, showing it absorbed fluid unevenly.

So they set out to invent a better tampon.

The two spent four years working with fluid mechanics experts, engineers and manufacturers. The result: A spiral-shaped tampon that they say is designed to offer more-even absorption to funnel fluid into the core.

The first prototype used to make tampons which led to other prototypes which led to the Sequel tampon.

Now, their San Francisco startup, Sequel, has $5 million in funding and their product is undergoing Food and Drug Administration review. They’ve lined up a manufacturing partner in Israel and hope to release the Sequel Spiral tampon this year, selling direct to consumers.

Pricing hasn't been set, but they want to make it accessible and affordable, they said. To boost visibility, they’re lining up elite athletes for endorsements.

"I think their insights are dead on," said John Poccia, who spent 35 years at Johnson & Johnson working on customer products including OB tampons and Carefree pads. Sequel hired him as a consultant. "Tampon users know sometimes they pull a tampon out and parts of it are white which means it didn't wick blood as it should. This will last longer."

Of course, extra-absorbent tampons still carry the stigma of toxic shock syndrome. Risks of the rare and potentially fatal bacterial condition can be increased by the use of high-absorbency tampons. In the 1980s, manufacturers lowered tampon absorbency and recalled some brands.

Both women are careful to note that their invention is not more absorbent — just more efficient.

"Our goal is to have a regular tampon that just works better," Meyer said. "Our product is designed to absorb more evenly but is not designed to have a higher absorbency capacity."

As with other tampons, it's not supposed to be worn more than eight hours.

Sharra Vostral, a history professor at Purdue University and author of "Toxic Shock: A Social History," said that the Sequel Spiral appears not to have risk issues for the syndrome since it does not include more material. She applauded the idea of a fresh approach.

Memorabilia and ephemera on the shelves at the Sequel office in San Francisco.

"It's exciting in that it is something different in the tampon category," she said. "The heavy legacy of toxic shock syndrome has been a big cloud" over new ideas.

Chella Quint, a menstrual activist based in Sheffield, England, who founded Period Positive, a menstrual literacy campaign, and wrote "Own Your Period" and "Be Period Positive," also said she was encouraged to see more creativity in menstrual products.

"Innovation in the menstrual space is evidence that internalized menstrual shame is starting to lift," she said. "Any innovation grows out of a zeitgeist. An era where periods are starting to be talked about more openly allowed (Sequel's inventors and others) to feel comfortable and empowered to innovate."

The spiral tampon, which uses a plastic applicator and is made of cellulose fiber like many other tampons, bucks the current trends in some ways, however. Social media buzz about new period products focuses on ones that don't end up in landfill, such as menstrual cups and discs, cloth pads and period panties.

But while those reusable products are more environmentally friendly, the Sequel research showed that they don't appeal to many women.

"We found that women in the U.S. are more uncomfortable using menstrual cups because you need to get intimate with yourself to insert and place them correctly and the removal process can be daunting and messy," Calabrese said.

Lara Freidenfelds, a historian of health, reproduction and parenting, and author of "The Modern Period: Menstruation in Twentieth-Century America," said that most updates to period products have centered around pads — adding wings and sticky strips, for instance, although those happened decades ago.

"Seeing how receptive people were to that stepwise innovation with pads makes me think if you can do something that's noticeably better with tampons it will be successful if it's good and not too much of a price increase," she said.

Still, changing brands or styles is a big hump, she said. "The word would have to get out, that these leak less. If they’re enough better that people can tell the difference, I would expect them to become popular and other companies to figure out a way to copy them. This could push the envelope a bit and get us something across the board better."

To forestall copycats, Sequel has patents on the tampon's design, utility and the proprietary equipment and processes it uses to manufacture it.

For Meyer and Calabrese, one big goal is to encourage teens and tweens not to see periods as daunting.

"Young girls drop out of sports at an alarming rate at the time they get their periods," Calabrese said. "We’re passionate about keeping young girls in sports, understanding the link between that and reliable menstrual products."

Reach Carolyn Said: [email protected]; Twitter: @csaid

Correction: This article has been updated with the correct maximum time a tampon is supposed to be worn. It is eight hours.