Best Underwear for Working Out: A Gym Guide by Workout

Underwear is the last thing you think about before a workout, and the first thing you notice when it's wrong. The pair that rides up mid-squat, the lace that chafes on a run, the cotton that's soaked through by your second set. What you wear underneath makes more difference to a workout than most people give it credit for.

The honest answer to "what's the best underwear for working out" is: it depends what you're doing. Running, lifting, yoga and a sweaty HIIT class all ask for something slightly different. Here's a no-nonsense guide, sorted by workout, plus the things that matter no matter what you're doing.

What actually matters in workout underwear

Before the specifics, four things separate underwear you forget you're wearing from underwear you fight with the whole session.

It has to breathe and handle moisture. This is the big one. Cotton feels soft but it absorbs sweat and holds onto it, so it stays damp against your skin the whole workout and long after. A breathable fabric that releases moisture faster keeps you cooler and drier. That's why we make ours from modal, which is more breathable than cotton and doesn't cling once you start sweating.

It has to stay put. Repetitive movement is where cheap underwear fails. Squats, lunges and running all work a short leg or a thin waistband loose until you're adjusting between reps. A leg that grips without digging, and a waistband that doesn't roll, is the difference between forgetting about it and fixing it every five minutes.

It shouldn't chafe. Seams in the wrong place, lace edges, or thighs rubbing skin-on-skin all turn into raw patches over a long session. Flat, bonded edges and a bit of leg coverage solve most of it.

It shouldn't show. Under thin leggings, a lacy or seamed pair prints straight through. Flat, hot-pressed edges sit invisible where a stitched seam would show a line.

The best underwear by workout

Running

Running is repetitive, sweaty, and long, which is the hardest combination for underwear. You want something breathable that won't hold moisture, with a leg long enough to stop your thighs rubbing over the miles. A boxer brief with a bit of leg is the sweet spot for most runners: enough coverage to stop chafe, light enough that you don't feel it. If your thighs touch or you're running distance, size up the leg to a longer biker length.

Lifting and strength training

Lifting isn't about sweat so much as position: deep squats, hip hinges, lunges. That's exactly where a short leg climbs and a thong migrates. Go for more coverage, not less. A boxer brief stays anchored through the full range of motion, so you're thinking about your form and not your underwear.

HIIT, bootcamp and circuits

Fast, explosive, sweaty. This is the workout that exposes anything that rides up or holds moisture, because you're changing direction constantly and sweating hard. A longer, breathable pair that grips the leg is your friend here. If one workout is going to make you notice your underwear, it's this one, so pick your most stay-put pair.

Yoga and Pilates

Different problem entirely. Here it's not sweat or movement, it's thin leggings and revealing positions. The complaint we hear most is fabric bunching at the front in a forward fold. A flatter, wider cut sits smooth instead of gathering into the middle, so a boyleg or boxer works better than a narrow bikini. Thin and seamless matters more than coverage.

Spin and cycling

On the bike you're sitting on a seam for 45 minutes, so the last thing you want is more seams underneath. A smooth, flat, breathable pair with no bulky edges sits comfortably against the saddle. Skip anything with thick seams or lace at the leg.

Should you even wear underwear to work out?

Fair question, and you'll hear both answers. A lot of leggings and bike shorts come with a built-in gusset and are designed to be worn on their own, and plenty of people do exactly that, especially for a short, sweaty session where an extra layer feels like too much. There's nothing wrong with going without if that's comfortable for you.

That said, many people prefer a thin layer of breathable underwear for hygiene and for a barrier between skin and shared equipment or thin leggings. If you do wear a pair, the rules above still apply: breathable, stays put, no chafe. The worst option is a thick, sweat-holding pair that traps everything against your skin.

The one habit that matters most: change out afterwards

Whatever you wear, the single best thing you can do for comfort and freshness is get out of sweaty underwear and leggings soon after you finish, rather than running errands in them for the rest of the afternoon. Sitting in damp fabric is what leads to irritation and that not-so-fresh feeling. A breathable fabric that dries faster helps, but nothing beats a quick change. This is general information, not medical advice, so if something doesn't feel right, check with your doctor.

What to look for, and what to skip

Look for: a breathable fabric like modal that releases moisture rather than holding it; flat, bonded or hot-pressed edges that won't dig, roll or show; enough leg to stop your thighs rubbing; and a smooth, tagless build with no scratchy seams.

Skip: all-cotton (holds sweat), lace or heavily seamed pairs (chafe and print through leggings), and anything with a thin elastic leg that rolls up the moment you move.

Which one for you?

Each workout above has its pick, but if you want the short version: the 5″ boxer is the do-it-all default, the 8″ biker is for high movement or fuller thighs, and the 3″ boyleg is your yoga and under-leggings option. All come in breathable black modal, XS to 5XL.

If you want the deeper dive on going invisible under thin leggings specifically, we cover that in what to wear under leggings, and if chafing is your main issue, how to stop chub rub goes further on that.

Frequently asked questions

What is the best underwear for running?

A breathable pair with a bit of leg, so it won't hold sweat and won't let your thighs rub over distance. A boxer brief suits most runners; go longer if your thighs touch or you run distance.

Should you wear underwear when working out?

It's up to you. Many leggings and bike shorts have a built-in gusset and can be worn alone. If you prefer a thin layer for hygiene or a barrier under thin leggings, choose a breathable pair that stays put and doesn't chafe.

Is cotton underwear bad for the gym?

Cotton isn't dangerous, but it absorbs sweat and holds it against your skin, so it stays damp through a workout. A breathable fabric that releases moisture faster, like modal, feels cooler and dries quicker.

What underwear stops chafing during exercise?

A pair with enough leg to keep your thighs from rubbing, plus flat, bonded edges rather than seams or lace. A longer boxer or biker length is the most reliable for high-movement workouts.

What's the best underwear for yoga?

Something thin, flat and smooth that won't bunch at the front during forward folds or print through thin leggings. A boyleg or boxer cut works better than a narrow bikini.

How do I stop underwear riding up at the gym?

Choose a longer leg with a flat, hot-pressed hem that grips your thigh instead of a thin elastic edge that rolls. The longer the leg, the more reliably it stays put through squats, lunges and running.

Should I change out of my underwear after a workout?

Yes, when you can. Getting out of sweaty underwear and leggings soon after you finish helps you stay fresh and comfortable, rather than sitting in damp fabric all afternoon.

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