How often should you change underwear

Sep 12, 2026

Short answer: Underwear should be changed once a day. If you have been sweating, training or out in the heat, change again, because the fabric holds on to moisture and skin oils close to your body.

Once a day is the rule

One day is enough for sweat and skin oils to settle in the fabric. Underwear sits directly against your skin all day and collects everything, even when you have done nothing special. A clean pair every morning is the simple rule, however little you have moved. See bamboo joggers for men.

Why one day is enough

Skin gives off moisture and oil all the time, even while you sleep or sit still. Most of it is taken up by the innermost layer, which is your underwear. After a day the fabric is no longer clean, even if it looks it and does not smell yet. The smell usually comes on day two, and by then it is too late.

Change again after training

A sweaty piece turns cold and starts to smell. After a run, a gym session or a long bike ride, your underwear is damp and will not dry on its own while you wear it. Change into a clean pair when you finish, even if you changed that morning. See bamboo sweatpants for men.

Pack a spare pair in your bag

If you train after work or at lunchtime, the easiest thing is to keep a spare pair of underwear in your bag. Then you can change straight after your shower and avoid putting the damp pair back on. A small cloth bag for the used pair keeps it separate until it goes in the wash at home.

Hot days need two changes

At thirty degrees, one day counts as two under normal conditions. You sweat more, even when you barely move, and your underwear gets damp faster. On a hot summer day it makes sense to change at midday or in the evening before you head out again. See bamboo sweatshirt for men.

How many pairs you need

At least seven. That lets you wash once a week without running out. If you train several times a week or it is summer, you need a few more, as you use more than one pair a day. More pairs also spread the wear, so each one lasts longer than if the same few are worn again and again.

Wash and dry properly

Underwear is washed after every wear. Follow the care label and let it dry completely before it goes in the drawer. Underwear put away damp can get a musty smell even though it has been washed. Drying indoors in winter takes longer, so allow for an extra pair or two.

If your skin reacts

If you notice irritation, itching or redness where your underwear sits, changing more often and trying another material may be worth a go. If it does not improve or keeps coming back, talk to your doctor. There can be many causes, and it is better to have it checked than to guess.