Like a limited-edition capsule collection—or prized concert tee (think sold-out sensations like Justin Bieber’s Purpose pieces or Kanye West’s Life Of Pablo items)—the private clothing labels of certain boutique fitness brands have become a status symbol all their own—even for people who’ve never worked out there.

“Before, clients would take a class, then buy merch; now, customers walk in to buy [something] they saw on Instagram—and then try a class for the first time,” says Sarah Levey, co-founder of Y7, the buzzy, hip hop-driven hot yoga studio in New York City and Los Angeles. “People are proud to be living a healthy lifestyle and want to make a statement in what they wear—and fitness studios foster communities.”

The designs for the brand’s workout wear, which ranges from $60 shorts to $250 bomber jackets, are inspired by the same beats that bump from its playlists. “Hip-hop concerts inspire the experience we create at Y7, from the class to the apparel,” Levey explains. “Our class is the show, our instructors are artists—and our merchandise plays off this concert-esque environment.”

“People write us on social, stop us in the studio, and even try to buy it off the backs of instructors—we’ve even seen items on eBay.”

Anything emblazoned with the studio’s signature Namaste Hands motif is pretty much guaranteed to move faster than the flows of its vinyasa sequences. “Praying hands are a reoccurring symbol in yoga and hip-hop culture that resonate with our audience,” explains the yogi. Tanks and leggings covered with phrases like “Money Cash Flows” and “A Tribe Called Sweat” lure new customers in via social media. “We’ve seen Y7’s Instagram presence drive significantly more foot traffic to the studios,” Levey says.

And music plays a big part in creating the vibe at the nearby New York Pilates, too. (Creative director Brion Isaacs, who runs the company with his wife, Heather Andersen, chalks up the studio’s aesthetic to his past life as a drummer and DJ—plus his father’s career as a fashion designer.)

“I took a lot of cues from him in terms of spotting trends before they catch on,” Isaacs says. “Heather and I wanted to make items we’d actually wear—we took inspiration from vintage t-shirts, concert posters, and artwork.” The couple used it to create small batches of the types of tees, tanks, and sweatshirts ($30–$80) you’d pick up from a merch table at one of NYC’s iconic rock venues. “Everyone from Emma Roberts and St. Vincent to Pilates instructors and students from Australia and Russia,” have purchased a piece from their private label, he says.

Part of what makes them even more desirable? “Once they’re gone, they’re gone!” Isaacs says. “Sometimes people luck out when we find a couple extra pieces from the archive and post them on Instagram—which usually sell out in [under] five minutes.” (The latest NYP drop was gone at all three locations and online in under 24 hours.)

Despite obvious demand, Isaacs and Andersen opt not to reissue any of their designs. “People write us on social, stop us in the studio, and even try to buy it off the backs of instructors; we’ve even seen items on eBay,” Isaacs says. “I’m excited to make items that people love, but even more excited to create items with real value, since they’re scarce.”

Another cool-girl, downtown Manhattan studio, Sky Ting Yoga, similarly keeps its collections exclusive. “We want pieces to feel special, unique, and fun to collect,” says its co-founder Chloe Kernaghan of the tightly edited runs. (T-shirts typically go for around $35.) A pocketed boxy tee in pink and white with logo prints, yin-yang symbols, or Matisse-inspired leafs, has sold out with each re-release. (A new delivery arrives soon, FYI.) “I’ve even gotten texts from friends seeing strangers in cities outside New York wearing our gear, which is really cool,” says the yogi.

While their aesthetics are each totally unique, the one thing all three studios have in common is that they inspire the same type of die-hard allegiance from their fans as, well, actual rockstars. And it would seem the sort of cult following that creates waitlist-only class schedules also translates into t-shirt sales. Which makes sense, Isaacs says. His theory? “If you’re spending five to six hours a week somewhere or doing something, you usually want to rep it.” And even if you’re not, say, perfecting your boomerang, who doesn’t want to rock a badass tee with a good vibe?

For more fitness-fashion must-haves, here are the coolest activewear items (other than t-shirts) and sneakers of the summer.