This Portlander Manufactures the World’s Best Form-Fitting, Wedgie-Proof Underwear

“We make underwear for big butts, big stomachs, big thighs, and also for people with tiny butts and tiny thighs.”

For much of her adult life, Celeste Sipes worried about her underwear.

“I was born with a really big butt,” she laughs, “and all my underwear I’ve ever worn had just ridden straight up. I really was always depressed about underwear.”

Sipes’ undie woes finally came to an end in 2005 after her sister moved to New Zealand and spotted some briefs decorated with rocket ships. The print reminded her of the tighty-whities worn for good luck by the protagonist in Calvin and Hobbes, Sipes’ favorite comic strip, so she bought a pair and shipped them off to her sibling. More than the pattern, what was even more impressive was how the underwear molded to her body when she slipped them on.

“I literally almost cried,” Sipes says. “I was like, ‘Oh my God, they fit!’ And they fit everywhere. They hugged, they were secure.”

Though she didn’t realize it at the time, that was the first step toward the launch of Thunderpants USA, with Sipes in the ownership role of the Portland-based offshoot.

Sipes, who grew up in Kalispell, Mont., learning to sew under her mother’s guidance, has actually spent years in the clothing industry. When Sipes opened West End boutique Radish Underground in 2008, one of the first products she made sure she could carry was that life-changing underwear line, becoming the company’s first American account. Demand for Thunderpants grew so much, the business reached out to see if Sipes would helm a U.S. spinoff.

Now, bolts of brightly colored fabric—some with playful patterns like an explosion of avocados or galloping ponies—are cut and sewn at Evergreen Apparel Manufacturing in Hillsboro. Made with a proprietary 90-10 blend of organic cotton and Spandex, the unique underwear has garnered a passionate following inspired equally by its fabric and its fit.

“Because the fabric has such nice bounceback and retention to it, it just stays in place all day,” Sipes explains. “They’re wedgie-proof, which is sort of our main claim to fame.”

Most of all, Sipes loves the fact that a seemingly simple undergarment can help women feel confident in their own skin.

“We make underwear for big butts, big stomachs, big thighs, and also for people with tiny butts and tiny thighs,” she says. “It’s so stretchy, it really fits so many different body types. I love how comfortable and sexy people feel. And powerful! A lot of people say, ‘I feel like a superhero in my Thunderpants.’”