If you are wondering how to wash period underwear, the routine is actually very simple. Rinse in cold water, machine wash at 40°C, skip fabric softener and let your pairs air dry.
Once you know those basics, period underwear fits easily into your normal laundry routine. Here is everything worth knowing about washing, drying and keeping your pairs fresh.
Can you machine wash period underwear
Yes. THATDAY period underwear can be machine washed at 40°C together with your other clothes. There is no need for a separate load. Just rinse the pair in cold water first and avoid fabric softener.
How to wash period underwear step by step
Here is the full routine from the moment you take a pair off.
- Rinse the pair in cold water after wearing it until the water runs clearer. Do not use soap during the rinse.
- Machine wash at 40°C together with the rest of your clothes.
- Skip fabric softener and avoid rubbing soap directly onto the absorbent area. You can use your regular laundry detergent as usual.
- Let the pair air dry rather than using the tumble dryer.
That is all it takes. You can also see the care routine in action on our THATDAY Instagram.

Do you need a special detergent?
No. Your regular laundry detergent is fine. Just skip fabric softener and avoid rubbing soap directly onto the absorbent area.
How to dry period underwear
Let your period underwear air dry after washing. Hanging your pairs or laying them flat protects the waterproof layer and keeps the elastic in shape, which is a big part of why they last for years, while a hot tumble dryer can wear that layer down over time. Because pairs need time to dry, most people keep at least two or three in rotation, so there is always a fresh one ready while the others dry.
How to remove odour or stains
If a pair needs a little freshening up, dilute white vinegar with water in a 1:3 ratio. Gently work the solution into the absorbent area and leave it for no longer than 20 minutes.
Afterwards, wash the pair in the washing machine as usual. For extra freshness, we recommend adding diluted vinegar in a 1:5 ratio during the wash. If possible, let the pair air dry outside in the sun and fresh air.
For lighter coloured pairs, you can also use a citric acid solution. Dissolve around 50 to 100 g of citric acid in 7 litres of water and leave the pair to soak overnight. Avoid chlorine bleach.
How often should you wash period underwear
Wash your period underwear after each wear. You do not need to run the washing machine straight away. Rinse the pair in cold water first and add it to your next laundry load.
Having a few pairs in rotation can make things easier during your period. If you are still building your collection, you can browse the full THATDAY period underwear collection and pick up a couple of spares.
If you need to change while you are away from home, fold the used pair with the absorbent side facing inward and keep it in a small wet bag or pouch. A waterproof zipper pouch can make this easier when you are travelling, at work or out for the day. Rinse the pair once you are home and wash as usual.
A Simple Period Underwear Care Routine
Once you know how to wash period underwear properly, there is not much to think about. Rinse in cold water, wash at 40°C, skip fabric softener and let your pairs air dry.
Curious about what makes period underwear absorbent in the first place? Read what period underwear is and how it works to learn more about the layers inside.
Frequently asked questions
Yes. A quick cold water rinse right after wearing lifts most of the blood and stops stains from setting, which makes the machine wash far more effective.
Yes. After the cold rinse you can machine wash your pairs at 40 degrees together with the rest of your laundry.
Fabric softener coats the fibres and reduces how much they can absorb, so a pair will not perform as well. Washing without it keeps the layers working properly.
No. Always air dry. The dryer runs hot and can damage the waterproof layer over time, which shortens the life of the pair.
Soak the pair in a mix of one part white vinegar to three parts water for no longer than 20 minutes, then wash as usual. Regular correct washing usually keeps odours away in the first place.


