Common Underwear Care Mistakes and How to Avoid Them

Quick answer

The biggest underwear care mistakes are washing too hot, using fabric softener, and tumble drying. For most cotton and Fairtrade pieces, a cool gentle wash and air drying will keep them comfortable and make them last. For swimwear, rinse in cold water after every wear and never put it in the dryer.

You’ve invested in comfortable, well-made underwear. But a few small habits can shorten its life fast. We hear the same myths again and again: hot water kills bacteria, fabric softener makes things softer, and a hot dryer is fine as long as the cycle is short. None of these are true for everyday underwear.

This guide busts the most common underwear care mistakes using what we know about our own fabrics. We’ll cover cotton, swimwear, and crops, and give you simple rules that actually work.

Myth: Hot water cleans better

Hot water can set stains and break down elastic fibres over time. Unless a care label specifically says otherwise, cool or warm water with a gentle detergent is enough for everyday soil and sweat. For cotton drill and cotton jersey pieces, heat also encourages shrinkage. If you want to keep the fit you bought, keep the temperature down.

For swimwear, heat is even worse. Nylon/spandex blends are sensitive to heat and chlorine. A cool rinse after every swim removes salt, chlorine, and sunscreen without stressing the fibres.

• Wash cotton and cotton-blend underwear in cool or warm water (max 30°C/86°F).
• Rinse swimwear in cold water immediately after wearing.
• Never use hot water on prints or dark colours if you want them to stay bright.

Myth: Fabric softener makes underwear softer

Fabric softener leaves a waxy coating on fibres. On cotton, that coating can reduce absorbency and trap odours. On swimwear and stretch fabrics, it can degrade elasticity. If you want softness, use a gentle, residue-free detergent and avoid over-drying. A short tumble on low or line drying in the shade keeps cotton feeling soft without coatings.

For Fairtrade crops and camis, softness comes from the cotton itself and how you wash it, not from added chemicals. Skip the softener and your garments will stay fresh longer.

• Skip fabric softener entirely for all underwear and swimwear.
• Use a small amount of gentle detergent; too much leaves residue.
• If you want extra softness, add a half-cup of white vinegar to the rinse cycle (not for swimwear).

Myth: Tumble drying is fine on low

Even low heat in a dryer can shrink cotton and weaken elastic over time. The tumbling action also causes pilling and wear. Air drying is the single easiest way to make underwear last. Hang or lay flat in the shade. If you must use a dryer, use the lowest setting and remove items while still slightly damp.

Swimwear should never go in a dryer. The heat breaks down spandex, leading to sagging and loss of shape. After rinsing, gently squeeze out water (don’t wring) and lay flat to dry.

• Air dry all underwear and swimwear whenever possible.
• If using a dryer, choose low heat and remove promptly.
• Never put swimwear in a dryer.

Myth: You can wash everything together

Sorting matters. Heavy items like jeans or towels can abrade delicate crops and camis. Zippers and hooks can snag cotton jersey. Wash underwear and crops in a mesh bag with similar lightweight items. For indigo-dyed pieces, wash separately for the first few washes to avoid colour transfer.

Also consider the wash load size. Overloading prevents proper rinsing and can leave detergent residue, which irritates sensitive skin.

• Use a mesh laundry bag for crops, camis, and underwear.
• Wash indigo-dyed items separately for the first few washes.
• Don’t overload the machine; leave room for clothes to move.

Verdicts on common underwear care myths

• Hot water cleans better: False. Hot water can set stains, shrink cotton, and damage elastic. Use cool or warm water instead. Wash at 30°C/86°F or cooler.
• Fabric softener is good for underwear: False. It leaves a coating that reduces absorbency and can degrade stretch fibres. Skip it entirely. Use a gentle detergent and skip the softener.
• Tumble drying on low is safe: Not for long-term care. Even low heat can shrink cotton and weaken elastic. Air dry whenever possible. Air dry all underwear and swimwear.
• All fabrics can be washed together: False. Heavy items and zippers can snag delicate crops and camis. Sort and use a mesh bag. Wash like with like, and use a laundry bag.

Product facts that matter for care

• Sky Rise Scratchy: Extra high-waisted full brief that sits high on your natural waist and tapers in at the top. The high waistband can lose shape if washed in hot water or dried on high heat. Cool washing and air drying help it stay put all day.
• Ngawi Swim Crop Popeye: Constructed in very durable nylon/spandex. Nylon/spandex is sensitive to heat and chlorine. Always rinse in cold water after swimming and never tumble dry to keep the fit firm.
• Cotton Cami Dress Black: Made from 100% cotton. Cotton is breathable and easy to care for, but hot water and dryer heat can shrink it. Wash cool and air dry to maintain the floaty fit.
• Original Crop Top Artichokes: Single layered garment for gentle support, soft on the shoulders. The soft cotton construction can be damaged by fabric softener and harsh washing. Skip softener and use a mesh bag to prevent stretching.

Good care doesn’t have to be complicated. Cool washes, no softener, and air drying will keep your Thunderpants feeling comfortable and looking good for longer. Treat your underwear like the investment it is, and it will reward you with everyday comfort.