Underwear and hygiene and how often it should be changed

Short answer: Underwear should be changed every day, and more often if you have been sweating. It is the one area where there is no trade off to make, neither for the fabric nor for the environment, because underwear sits closer to the skin than anything else you wear.

Every day at a minimum

Underwear lies directly against the skin and collects sweat, skin cells and bacteria through the day. One day is enough for it to need changing, even if it does not smell or look worn. This goes for briefs, boxers and undershirts alike. See bamboo underwear for women and bamboo underwear for men.

Why it cannot be stretched

With a shirt or trousers you can often wait to wash, since there is a layer between them and your skin. Underwear is that layer. It takes in most of what the body gives off, which is why an extra day makes the biggest difference here for both odour and comfort.

Twice on physical days

If you have sweated through, a change at midday does more for comfort than any other choice. Damp underwear chafes more, cools the skin and starts to smell sooner. If you work physically, exercise or it is a hot day, it pays to keep a spare set in your bag so you can change along the way.

After exercise

After a workout, change your underwear straight away rather than wearing it damp for the rest of the day. Shower, put on a clean set and put the used one in the wash. If you cannot wash it right away, hang it to dry first so the odour does not settle in the fibres.

Enough sets in the drawer

The whole difference lies in having enough sets to change without washing every other day. Ten sets is a comfortable number, as it covers a week plus a few extra for days when you change twice. Then you can gather your underwear into one wash a week instead of worrying about it.

Storing worn underwear

Put worn underwear in a laundry basket with some air around it, not in a closed bag. Moisture and warmth help bacteria thrive, and the odour becomes harder to wash out. If it is damp with sweat, hang it up to dry before it goes in the basket with the rest.

Washing at 40 degrees

40 degrees is enough for everyday underwear when you use a good detergent. 60 degrees is used when someone in the home is ill, but it wears more on the fabric and elastic. Wash underwear with similar colours and do not fill the machine completely, so the water can move freely. Read more in washing and care.

Fabric softener is not needed

Fabric softener does not make underwear cleaner. It leaves a thin film on the fibres that can trap odour and make the fabric worse at moving moisture. Bamboo viscose underwear is soft without softener, so you can safely skip it. If you want fresher underwear, an extra rinse is a better choice.

When to replace it

Even well washed underwear wears out over time. When the elastic has gone slack, the fabric has thinned or there is an odour that does not wash out, it is time for new pairs. It is easier to keep track if you replace a few sets at a time rather than the whole drawer at once.