How to Wash and Care for Period Underwear

Period underwear is a bigger upfront decision than a box of pads — you're buying something meant to last years, not a single cycle — which makes the care routine part of the product, not an afterthought. Done right, it's genuinely simple: three steps, none of them complicated. Done carelessly, it's the single fastest way to shorten the life of a pair that should otherwise outlast dozens of cycles.

The three-step routine

1. Cold rinse, first

Before anything else touches your Kiri pair, rinse it in cold water until the water runs clear. This isn't optional housekeeping — it's the step that keeps blood from setting into the absorbent core, the same way you'd rinse any stain before it dries. Warm or hot water at this stage does the opposite of what you want: heat can set protein-based stains rather than lift them.

2. Machine wash, inside a laundry bag

Once rinsed, it goes into the regular wash with the rest of your laundry — cold water, delicate cycle. A mesh laundry bag isn't strictly required, but it protects the gusset's layered construction from friction against zippers, hooks and heavier fabric, and it keeps the pair contained in the machine rather than tangled in the drum. Skip fabric softener and bleach: softener coats the moisture-wicking layer and blunts the exact property that makes the fabric work, and bleach breaks down the absorbent core over time.

3. Line dry, always

Air dry, out of direct sun where possible. This is the step people are most tempted to skip, and the one with the most consequences — tumble drying's heat and tumbling motion is hard on the leak-proof outer layer specifically, the part responsible for keeping everything contained. The fabric is quick-drying by design, so line-dried overnight is normally ready by morning, which is what makes a rotation of three to five pairs realistic without ever running out.

What actually shortens a pair's life

In order of how much damage they do: tumble drying, bleach, and fabric softener. All three are common laundry-day defaults for other clothing, which is exactly why they're the most common mistakes with period underwear — nobody's being careless, they're just running the routine they run for everything else. The fix isn't more effort, it's a different three steps for one category of laundry.

How long a well-cared-for pair actually lasts

Cared for this way, a pair stays soft, leak-proof and reliable for years — which is also the entire economic case for switching in the first place. A single pair, worn and washed correctly across several cycles a year, ends up replacing hundreds of individual pads or tampons over its lifetime. The care routine isn't a chore layered on top of that value; it's the thing that makes the value real.

Building a rotation

Most people managing a full cycle comfortably keep three to five pairs on rotation — daywear for lighter days, nightwear for heavier ones and overnight, with one pair always washed and ready while another is in use. If you're starting from zero, our bundle sets are usually the cheapest way to build that rotation in one order, and our size guide covers how daywear and nightwear differ if you're deciding what mix to start with.