What to Look For in Underwear for Exercise: A Practical Buying Guide

Quick answer

For most workouts, choose moisture wicking underwear with a high cotton or microfibre content, flat or laser-cut edges, and a cut that stays put. A full brief or mid-rise brief suits high-impact training and cycling; a Brazilian or high-cut brief suits lighter sessions. Skip cotton-only options for sweaty sessions if you can.

The right underwear for working out is the pair you forget you are wearing. That usually means a fabric that moves sweat away from skin, edges that do not dig in, and a cut that stays in place when you squat, run or stretch.

This guide explains how to judge fabric, cut and waistband before you buy, with practical checks you can do at home. It also covers when a g string or brief works better, and how to care for workout underwear so it keeps its shape.

Start with fabric: what actually handles sweat

Moisture wicking underwear moves sweat away from your skin so it can evaporate. Look for blends that include microfibre, polyamide or elastane, or cotton blended with a small amount of stretch. Pure cotton feels soft but holds moisture, which can feel heavy and cause chafing during long or intense sessions. If you prefer cotton, choose a cotton-rich blend with a mesh or lace panel for airflow, and save 100% cotton for rest days.

Check the gusset. A cotton gusset is a common feature in everyday knickers and can work for light exercise, but for high-sweat workouts a technical fabric throughout is more comfortable. Also look for flat seams or laser-cut edges, because raised seams rub when you move.

• Squeeze test: if the fabric feels slick and springs back, it is likely a wicking blend; if it stays damp and limp, it will hold sweat.
• Avoid thick elastic trims around the leg for running or cycling; they trap heat and can chafe.

Choose the cut for your workout

Cut affects coverage and movement. A full brief gives the most coverage and stays put during squats, lunges and cycling. A mid-rise brief with a low leg line is a good all-rounder for gym sessions and walking. A high-cut brief offers less coverage at the hip but can feel cooler for yoga or pilates. A Brazilian or cheeky cut has less back coverage, which some people prefer for low-impact workouts but it can ride up during running or jumping.

A g string or thong eliminates visible panty lines under leggings, but the narrow back can cause friction during high-impact or long-duration exercise. If you choose a g string, pick one with a soft, wide waistband and a cotton gusset, and test it during a short session before relying on it for a long run.

• For high-impact: full brief or mid-rise brief with flat edges.
• For low-impact or yoga: high-cut brief or Brazilian if you prefer less coverage.
• For visible panty lines under leggings: seamless brief or g string, but check for ride-up.

Waistband and fit checks that prevent ride-up

A waistband that rolls or digs in is a sign of poor fit, not just a style issue. Look for a wide, flat waistband that sits smoothly against your skin. Folded waistbands can feel soft but may roll during movement. Laser-cut edges are a good choice because they lie flat and do not create a ridge under leggings.

Fit should be snug but not tight. If the brief leaves red marks or you need to adjust it during a workout, size up or try a different cut. The gusset should sit comfortably against the body without pulling. If you are between sizes, choose the larger size for workout underwear, because movement and sweat can make a tight pair feel tighter.

• Do a squat test in the fitting room or at home: if the back rides up, the cut or size is wrong.
• Check that the leg openings do not cut into the crease of your leg; flat finishes are best.

How many pairs and how to care for them

Aim for at least three to five pairs of workout underwear so you are not washing after every session. Rotating pairs gives fabric time to recover its shape. Wash after each wear in cool water with a gentle detergent, and avoid fabric softener because it coats fibres and reduces wicking. Air dry flat or hang; heat from a dryer can break down elastane and cause edges to wave.

If you use a g string for workouts, hand wash or use a mesh bag to protect the narrow back. Replace workout underwear when the waistband loses elasticity or the fabric feels stiff or pilled. That is usually after 6–12 months of regular use, depending on how often you wear and wash them.

• Keep a separate small laundry bag for workout underwear to avoid snags.
• Skip the dryer; heat is the main cause of stretched-out waistbands.

Decision rules for buying workout underwear

• Fabric first: If you sweat heavily or exercise for more than 30 minutes, choose moisture wicking underwear with microfibre, polyamide or a cotton-rich blend. If you prefer pure cotton, keep it for light activity. Check the label: a wicking blend will feel slick and dry quickly.
• Cut by impact: For high-impact (running, HIIT, cycling), choose a full brief or mid-rise brief with flat edges. For low-impact (yoga, pilates, walking), a high-cut brief or Brazilian works if you prefer less coverage. Do a squat test: if the back rides up, size up or switch to a fuller cut.
• Edges and waistband: Laser-cut or flat seams prevent chafing and visible lines. A wide, flat waistband stays put; folded waistbands can roll during movement. Avoid thick elastic leg trims for running or cycling.
• G string or brief: A g string eliminates panty lines but can cause friction during high-impact exercise. A brief gives more coverage and stability. If you choose a g string, pick one with a soft waistband and cotton gusset. Test a new g string on a short workout before a long session.

Kayser options that suit exercise

• 2 Pack Sleek & Smooth Lace Mid Rise: Made from smoothing lace and soft microfibre with laser-cut edges for a no-show finish under clothing. The microfibre blend and laser-cut edges reduce friction and visible lines, making these a strong choice for gym sessions under leggings.
• Be You High Cut Mesh Brief: All-over mesh design with a wide folded waistband, mid-rise waist and high-cut leg line finished with sheer organza elastic. The mesh fabric is lightweight and breathable, and the high-cut leg gives freedom of movement for yoga or pilates, though the folded waistband may roll during high-impact work.
• 2 Pack Daily Essentials Cotton & Floral Lace Full Brief (465N): Cotton body with a wide lace band in lightweight floral lace; full-coverage brief. The cotton body is soft and breathable for low-sweat activities, but it will hold moisture during intense workouts; best for walking or rest days.

Who this advice is for

Best for

• Anyone building a workout underwear drawer for gym, running or yoga
• People who want to reduce chafing and ride-up during exercise
• Shoppers looking for moisture wicking or seamless underwear for exercise

Not for

• Those seeking luxury lingerie for special occasions rather than performance
• People who only need everyday cotton briefs for low-activity days

Buy workout underwear by fabric, cut and edge finish, not by style alone. Start with a moisture wicking mid-rise or full brief, check the waistband and leg openings, and rotate at least three pairs. Replace them when the elastic goes. That is how you stay comfortable through every session.