How to Choose the Right Underwear for Exercise

Quick answer

For most workouts, choose breathable sports briefs or a seamless gym underwear style in a smooth microfibre or a cotton-and-lycra blend, with a flat waistband and no thick side seams. If you sweat heavily or train in heat, prioritise moisture wicking underwear over pure cotton; if you lift or run in loose shorts, choose a cut that stays put, such as a brief or a boxer with grip bands.

Underwear is the layer you notice most when it fails: it rolls, rubs, traps heat or shows through leggings. The fix is not one universal pair but a short set of decisions about fabric, cut and waistband, matched to how much you sweat and how much you move.

This guide walks through those decisions in order, then shows how real DIM styles fit each rule, from a microfibre sports bra for younger athletes to a men's cotton boxer with grip bands. Use it to build two or three reliable pairs instead of guessing every gym day.

Start with fabric, not colour

Fabric decides how underwear feels after ten minutes of effort. Microfibre is smooth, light and dries quickly, which suits intense or sweaty sessions and reduces the chance of visible lines under leggings. Cotton blended with lycra stays soft and breathable but holds moisture longer, so it works best for low-sweat activity, strength training in a cool room or everyday wear.

If you sweat heavily, look for moisture wicking underwear rather than pure cotton. If your skin is sensitive or you train in air conditioning, a cotton-rich blend can be the more comfortable choice. There is no single winner: match the fabric to the session, and keep one of each in rotation.

• Hot yoga, running, HIIT: choose quick-drying microfibre.
• Light gym work or cool weather: cotton-lycra blends are fine.
• If you are unsure, buy one pair of each and test on two different sessions.

Choose the cut that stays put

Movement decides cut. A string or brief limits fabric at the back and reduces visible lines, but on long runs some people prefer slightly more coverage to avoid friction. A short or boy-short style stays in place under loose shorts, while a boxer with grip bands on the thighs is the most stable option for men who find regular boxers ride up.

The key rule: the smaller the movement in the garment, the less chance of chafing. If your underwear shifts when you squat or sprint, the cut is wrong for that activity, regardless of size.

• Running and cycling: low-coverage brief or string in microfibre.
• Lifting and team sports: short-style brief or boxer with grip bands.
• Loose shorts: add coverage so the fabric does not bunch.

Waistbands and seams do the quiet work

A flat, wide waistband distributes pressure and stops rolling during bends and twists. Jacquard or logo waistbands are fine as long as the elastic is soft and sits flat against the skin. Thick side seams are the usual cause of rubbing under tight leggings, so seam-free or bonded edges are worth seeking for high-movement sessions.

Check the inside of the waistband, not just the look. If it feels stiff or has a hard edge, it will dig in after twenty minutes. Soft, thermo-bonded finishes are a practical choice for anyone who reacts to traditional stitching.

• Press the waistband against your wrist: if it digs, it will dig at the gym.
• Turn the garment inside out and feel for raised seams.
• For leggings, choose a colour close to your skin tone to reduce show-through.

Fit rules that prevent chafing

Underwear for exercise should fit closer than everyday underwear but never compress. The leg opening should sit flat against the skin without cutting in; if you can see a dent when you stand, size up. The gusset should stay in place when you lift one knee, and the waistband should not need pulling up after a set of squats.

For sports bras, the band is the support: it should be snug on the ribcage and level all the way around, with straps that do not slide off the shoulders. A bra that rides up usually means the band is too loose, not that the cup is wrong.

• Test in a mirror: squat, hinge and reach overhead before deciding.
• If it leaves red marks that last, go up one size.
• Wash after every session to protect the elastic and the fabric's quick-dry finish.

Decision rules for buying workout underwear

• If you sweat heavily or train in heat: Choose quick-drying microfibre over pure cotton, and favour a low-coverage cut such as a brief or string to reduce fabric against the skin. Moisture wicking underwear is the priority, not the colour or the logo.
• If you run or cycle in tight leggings: Pick a seamless or bonded-edge style in a colour close to your skin tone, so lines and show-through stay minimal. Test under your actual leggings in daylight before committing to a full pack.
• If you lift, play team sports or wear loose shorts: Choose a cut with more coverage, or a boxer with grip bands on the thighs, so the fabric does not shift during squats and sprints. Stability beats minimalism when the movement is unpredictable.
• If you are between sizes: Size up for the leg opening and keep the waistband snug; a leg that cuts in will chafe long before a slightly relaxed waist becomes a problem. Fit the leg opening first, then check the band.

DIM styles that match these rules

• Brassière de sport blanche DIM Pocket Micro Girl: White microfibre sports bra with a swimmer's back, wide straps and an elastic band for support, finished with a jacquard waistband carrying DIM logos. The wide straps and racer-style back keep the bra stable during physical activity, and the microfibre dries faster than cotton, which suits younger athletes who train several times a week.
• Jupe short de sport femme microfibre Bleu Nuit Dim Move: Microfibre skort in deep navy with a quick-drying fabric, built-in shorty, side slit, integrated pocket and a graphic piping detail. The built-in shorty secures movement and removes the need for a separate pair underneath, while the quick-drying microfibre and side slit suit running, tennis or gym sessions in warm conditions.
• String femme en microfibre et dentelle Nude Dim: Nude microfibre and lace string with an ultra-smooth second-skin feel, a cut that limits marks at the back, and a light lace trim. The skin-tone colour and smooth microfibre make it a practical choice under light-coloured leggings, and the minimal back coverage reduces visible lines during low-impact training.
• Lot de 2 boxers homme en coton extensible Bleu Orange Stay and Fit: Pack of two cotton and lycra boxers in bright blue and orange with PowerGrip bands on the thighs and a wide jacquard waistband. The stretch cotton stays soft for everyday training, while the grip bands stop the legs from riding up during squats, lunges and running, which is the most common complaint with standard boxers.

Who this approach suits

Best for

• Anyone who trains three or more times a week and wants two or three reliable pairs instead of a drawer of random underwear
• Runners, gym-goers and team-sport players who deal with riding up, chafing or visible lines
• Parents buying a first sports bra for a teenager who needs stable support during physical activity

Not for

• People looking for compression or shapewear performance, which is a different product category
• Anyone who wants one pair to cover both formal wear and intense training; separate pairs work better
• Shoppers prioritising fashion colourways over fabric and fit for high-sweat sessions

Choose fabric for the sweat level, cut for the movement, and fit for the leg opening and band. Two or three well-matched pairs, rotated and washed after each session, will solve most exercise discomfort faster than any single 'best' pair.