Here's How to Properly Wash Period Underwear, According to a Laundry Expert

Tide Senior Scientist, Sammy Wang, MSE, is sharing her best tips and tricks, like which temperature to use and how to remove stubborn blood stains.

How to Wash Period Underwear
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Perhaps you've decided that tampon and pads just aren't for you, or you simply can't find any in stock due to the ongoing shortage. It may be time to turn to alternatives to get you through your period — including period underwear, which, surprisingly, tends to be more stress-free, comfortable, and is a more sustainable option. Plenty of brands make great, easy-to-wear period underwear (The Period Company, Thinx, Knix, even Aerie), but once the day is done comes the complicated part: figuring out how to wash them.

If you've ever wondered how to wash period underwear, well, you're not alone. We, too, have a ton of questions. Do you need to pre-wash period underwear? Can you throw them in with your regular clothes? What about drying? Will putting them in the dryer ruin them or make them less effective?

With all this in mind, InStyle decided to reach out to a laundry care expert for help. Tide Senior Scientist, Sammy Wang, MSE, solved all our period underwear dilemmas ahead, from what to do after you're done wearing them to how to remove stains that won't budge.

Does period underwear need to be pre-washed?

According to Wang, before you throw your period underwear into your washing machine, you'll need to rinse them out first.

"Always rinse period underwear in cold water after use until the water runs clear," she advises. "This helps to remove excess stains and prevent buildup."

Once you've completed that first step, Wang tells us to hold off on throwing them in with the rest of your dirty clothes. "Be sure to let period underwear air dry completely before putting it into the hamper."

Should you wash period underwear on gentle?

At this point, you likely know that it's recommended to wash everyday underwear on "delicate" or "gentle." But does that same rule apply to period underwear, which are heavily soiled? While Wang suggests looking on the manufacturer's site for specific care instructions and information, in general, yes, period underwear should still be washed as "delicates."

"Because period underwear is designed to wick, absorb, and hold liquids, it is constructed of several different layers of fabrics with different properties. These layers and fabric types can vary between brands, but to keep the garment in good condition, treat period underwear as 'delicates' and wash them in mesh garment bags, cold water, and avoid high-temperature machine drying."

How to Wash Period Underwear
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What temperature should you use when washing period underwear?

As previously mentioned, period underwear should be washed with cold water.

"Always check the instructions on the garment's care label first, but in general, it is best to wash in cold water with a stain and odor-fighting detergent like Tide Ultra Oxi with Odor Eliminators," Wang tells us. She adds that "cold water helps to preserve the layered fabrics that are used in period underwear to absorb and hold liquids," and that it also "helps to prevent staining."

How can you get rid of period blood stains that haven't lifted?

"We recommend pre-treating blood stains with a stain-fighting liquid detergent like Tide Ultra Stain Release," says Wang. "High quality detergents like Tide contain specialized ingredients that help to break down protein-based stains and lift them away."

In order to effectively remove blood stains from your period underwear, Wang shared the below step-by-step instructions and tips.

  • Rinse the stain with cold water until the water runs clear.
  • Apply a small amount of liquid detergent directly onto the stain and gently rub with a soft bristled toothbrush.
  • Let sit for 5-10 minutes before machine washing in cold with a stain and odor-fighting detergent like Tide Ultra Oxi with Odor Eliminators Power PODs.
How to Wash Period Underwear
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Is it bad to let period underwear sit in your laundry for days?

In short, the answer is yes. It's important to rinse period underwear in cold water after wearing them, and continue rinsing until the water runs clear.

"While this may be a little more work up front, this helps to prevent prolonged contact of stains with the fabric and helps prevent buildup over time," says Wang. "Always allow rinsed period underwear to air dry completely before putting it into the hamper. When you're ready to do a load of laundry, we recommend a stain and odor-fighting detergent like Tide Ultra Oxi with Odor Eliminators Power PODs that are designed for tough loads."

What are the best ways to ensure the longevity of period underwear?

Period underwear tends to cost more than your regular old briefs and boy shorts, so if you're shelling out money for a decent pair, you want to make sure it lasts longer than a few wears. This is why it's important to research the materials and the care instructions for different brands, ensuring you're washing your garments correctly.

"Because period underwear is designed to be both comfortable and absorbent, it is often constructed with several layers of fabrics like cotton, modal, spandex, nylon, and polyurethane," Wang tells us, before sharing Tide's recommendations on how to effectively wash and care for this specific combination of fabrics.

  • Rinse in cold water until the water runs clear after every use — this helps to prevent set-in stains and buildup over time.
  • Wash in a mesh delicates bag to prevent snagging and help protect the layered construction of period underwear.
  • Wash in cold water with a high-quality detergent like Tide Ultra Oxi with Odor Eliminators Power PODs, which is designed to work on all types of fabrics and help fight stains and odors.
  • Avoid high-temperature machine drying and line dry if possible.
  • Because different brands use different fabrics and constructions, always refer to the garment's care label, but in general, we recommend rinsing in cold water after use and treating period underwear like "delicates".
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