Paire Underwear Review

This new-to-the-US brand was founded in 2020 by best friends Rex and Nathan, two guys who couldn't understand why comfortable, functional, and sustainable clothing couldn't all exist in the same place. Rex brought the fabric technology expertise. Nathan brought the sustainability vision. Together, they started packing and shipping orders out of a garage and have since grown into a team of 20, with products sold internationally and a flagship store in Melbourne.

The mission never changed: make clothing that actually works for your body and doesn't cost the planet. No chasing trends, no throwaway pieces—just versatile, well-engineered essentials you'll reach for over and over again.

It's clearly resonating. Paire has amassed over 200,000 customers, landed a spot on Shark Tank Australia, and backs every purchase with a 100-day risk-free trial—which tells you something about how confident they are in what they've made.

The underwear is a great place to start.

A quick try-on is definitely not enough time to form a real opinion when it comes to underwear, so the game plan was to wear both styles for a month to see how they fare with everything on my agenda—under workclothes and loungewear, for sleep, workouts, and some light travel. I also didn't give them any special treatment, sending them right through the wash with the rest of my laundry.

I did give the Lipstick briefs one extra test. There's a lot of hype about how quickly these dry under a hairdryer, and while it's not part of my usual routine, I needed to see it in action.

I ordered the Classic Bikini silhouette, in mixed colors (sky blue, peachy, and midnight) in size XS-M (I'm a size 4 or 27 in jeans for reference). The Lipstick comes in a set of three or seven, not as an individual pair.

Fabric

I was pleasantly surprised with The Lipstick Underwear’s body fabric ( 64% recycled nylon, 36% spandex). From the description I knew it would be lightweight, but I was completely unprepared for how silky, stretchy, and quick-dry it would be. It's also sheer and slightly shiny, which is worth keeping in mind—but don't let that fool you into thinking these are delicate. I stretched them, sent them through the washer and dryer, and blasted them with my blow dryer, and they look and feel every bit as good as when they came out of the package.

How They Fit

These come in two sizes (XS-M and L-2XL), and you'll understand the sizing as soon as you hold a pair up and give them a stretch—they are incredibly stretchy. I sit in the middle of the XS-M range and have no doubt they'd comfortably fit the whole range.

These also get points for versatility. While they are definitely marketed for travel, they work just as well for every day. I wore these under jeans, dress pants, and workout leggings, and found them to be super comfortable, almost like wearing no underwear at all. These are not seamless, but the raw edges have no stitching or elastic immediately near them, so they leave no lines or indents under thin, tight pants. I wore these for a few Pilates workouts and they were not at all restrictive, didn't feel damp, and didn't get stinky with sweat. The silky material did slide around slightly but never bunched up, so I'd call them workout-approved.

I actually think these will be my go-to summer vacation underwear—they have pretty much every feature you'd want (breathable, lightweight, anti-odor) to keep you cool and fresh in hot, humid weather.

For Travel

The Lipstick underwear's whole claim to fame is being the best underwear for travel, and I totally see why. According to co-founder, Nathan Yun, “We made these because travel makes normal underwear annoying. Lipstick Underwear is genuinely comfortable, it packs down into a lipstick-size case, and we use RegSilk™ protein fibre in the gusset so it feels cleaner over long days.” They are incredibly light, and out of the packaging (I’ll get to that in a minute), I can seriously roll a single pair into a tight cylinder no bigger than a lipstick tube. I took these on an overnight trip to test the quick-dry claim—under a compact blow dryer, they were ready to wear in 87 seconds. It seriously took longer to brush my teeth. The body fabric was completely dry in well under a minute, though the gusset area took a little longer.

I can’t talk about the Lipstick Underwear without bringing up the packaging. The underwear came individually packed in these compact cardboard canisters, perfect for throwing in your gym or beach bag without worrying about them getting dirty or lost. They'd also make a great gift or a cute addition to a bon voyage care package, since you don't need an exact size and they're practical enough that anyone on the go will appreciate them.

For the BioTracker style, I ordered the Mid Brief in size small in the color Latte. Unlike the Lipstick, this style is sold as an individual pair.

Fabric

The BioTracker body fabric makeup is considerably different from the Lipstick: 88% super fine modal (made from tree fibre) and 12% spandex. Where the Lipstick Underwear feels super airy and silky, this pair feels soft, smooth, and light-but-substantial. The material is matte and opaque, which looks a bit more elevated, and I can genuinely appreciate that level of coverage. They also feature Paire's NudeTech™ technology, which basically means this seamless style will disappear under your clothes.

Both the Lipstick and BioTracker styles use RegSilk™ Protein Fibre in the gusset. This regenerated silk cocoon protein has both antibacterial and anti-smell properties, so you know you’ll be confidently fresh for everyday and even active days.

How They Fit

I had a moment of indecision with sizing and considered sizing up to medium, but I’m glad I stayed with the small. These are really stretchy, and I would say they’re true to size.

Fit-wise, these underwear are seriously so comfortable, and looked smooth under pencil skirts, jeans, leggings, and dress slacks. The raw edges are reinforced with thin, matching elastic that helps them to stay in pace and prevents the edges from rolling. I did notice a slight indent under my thinnest leggings, but they were undetectable otherwise. For workouts, these were my preferred style, since they stayed put and never needed adjusting. They are light and moisture wicking, and besides being anti-odor and staying that way even when sweaty, they moved with me and passed the squat test.

Innovative Features

The coolest thing about the BioTracker Underwear is the color-changing tracker on the back. It looks like a little logo, but is made with active proteins that sense external stimuli (sweat, skin contact, washing, whatever real life throws at it) and will gradually change colors. It’s time to replace the pair when the “P” and the line beneath are the same color. No waiting until the elastic is breaking down, or things are starting to look a little saggy (I’m looking at you, cotton pair that’s been hiding in the back of my drawer), the tracker is meant to let you know when it’s time for a refresh. After a full month of washing and wearing, I did not see a noticeable change in my tracker, so this pair still has lots of life left.

I love this feature, because I've tried the whole "replace every 6 to 12 months" rule and it never really works. Who actually remembers when they bought each pair? And not every style in your drawer gets the same amount of wear, so how do you know when to replace each one? The BioTracker takes all of that mental load off the table.

Insider tip: The brand notes that direct sunlight can cause the tracker to change color ahead of schedule, so avoid line drying for best results.

So, by the end of month, I ended up loving both underwear styles, but for very different reasons. Both definitely deserve to be in my rotation, but to really cash in on their best qualities here’s how I see them getting worn in real life.

The Everyday Upgrade: The BioTracker Brief

This is the style you stock your top drawer with when you want underwear that works under literally everything, and you want to take the guesswork out of when to replace your favorites. No waiting until your undies are falling apart, saggy, or just not staying fresh like they used to, the color changing tracker is like that pair’s own little warning light. Since it works by sensing what that specific pair has been through, the ones you reach for less often will naturally stay in rotation longer—which is actually really useful intel when it comes time to restock. The BioTracker comes in enough styles, from full coverage to thongs, that you could genuinely replace your whole drawer and never wonder "how old is this pair, exactly?" again.

The Travel-Friendly, Active Days Hero: The Lipstick Underwear

These little guys have a reputation for being the best travel underwear out there, and it's easy to see why: they pack down to nothing, can be sink-washed and dried with a hairdryer in under two minutes, and come in the most functional little canisters—perfect for tossing in a carry-on or gym bag. While they're versatile enough for everyday wear, my plan is to keep one in my gym bag as a backup, let the other two fill in the daily rotation gaps, and lean on all three heavily come summer and during vacation, when only the lightest, breeziest underwear will do.

Between both styles, my underwear drawer is basically sorted. Next up on my to-try list: Paire's bra collection, because who doesn't love a matching set?