The 13 Best Period Underwear for 2023

Cora’s The Free-To-Flow Period Underwear is a triple threat—it’s comfortable, absorbent, and affordable.

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The 13 Best Period Underwear of 2022

Saalt / Aerie / Proof

Though there’s an entire market dedicated to alleviating them, periods aren’t pretty. They’re often coupled with uncomfortable side effects, shame and stigma, and complex hormonal changes—and then there’s the blood (which isn’t just blood, by the way). To prevent leakage, there’s no shortage of options when it comes to feminine hygiene products. Pads and tampons are the most popular, but you can also try menstrual cups, discs, and period underwear.

Tested & Approved

Cora The Free-To-Flow Period Underwear is our top pick for comfort and value. It’s made with soft fabrics but impressed our tester with its ability to stay dry. Meanwhile, the Thinx For All Super Absorbency Brief is budget-friendly without sacrificing comfort and protection.

Period underwear is especially gaining traction for its sustainability and convenience. Unlike disposable pads and tampons, period underwear is washable and reusable. Mostly, period underwear is simply convenient. “Sometimes people prefer to free-bleed rather than have period blood collected inside of the vagina in a tampon or menstrual cup,” says Wendy Goodall McDonald, MD, FACOG, a board-certified obstetrician-gynecologist in Chicago. They’re also beginner-friendly and less intimidating to teens and tweens.

To find the best period underwear, we put some to the test. We tested more than a dozen pairs and assessed them based on absorbency, feel, and value.

Thinx and PFAS

Thinx recently agreed to settle a lawsuit (Dickens, et al. v. Thinx Inc.) about the presence of per- and polyfluoroalkyl substances (PFAS) and silver nanoparticles, which were found in multiple styles of the brand’s underwear following independent testing. The suit alleges that the presence of these chemicals is harmful to users and goes against the brand’s advertising as free of harmful chemicals and toxic metals.


After speaking to doctors and conducting research, we have kept Thinx products on our list. The OBGYNs and researchers we spoke to explained that people are exposed to PFAS daily—the compounds can be found in food wrappers, shampoo bottles, workout clothing, and in the living tissue of animals and humans worldwide. There is no clear evidence on the effect of PFAS in period underwear yet. You can read more about the possible presence of PFAS in period underwear below in our "Your Questions, Answered" section.

Our Recommendations

Best Overall: Cora The Free-To-Flow Period Underwear

Cora period underwear

Amazon

Why We Like It: The gusset absorbs liquid instantly and stays dry.

It’s Worth Noting: It’s mostly moisture-wicking, but there is a small amount of transfer.

Good period underwear should feel comfortable, absorb liquids, and stay dry. Our tester confirmed the Free-To-Flow Period Underwear from Cora does it all. After testing multiple pairs of period underwear, our tester said the Cora bikini is “hands down the best” for the soft texture without visible seams and instant absorbency. 

The absorbent gusset, which is similar to a fleece material, features a four-layer absorbent core. It’s designed to hold up to three regular tampons’ worth of fluids and can be worn on its own or as a backup method with other period products. Our tester found that it “instantly absorbed” three teaspoons of liquid with minimal transfer.

Price at time of publication: $25

Product Details:

  • Style: Bikini
  • Material: Cotton, polyester, and elastane
  • Size Range: XS–XXL
  • Care Instructions: Machine wash on delicate cycle
  • Absorbency Level: 3 regular tampons
period underwear test cora free to flow

Health / Leticia Almeida

Best Budget: Thinx For All Super Absorbency Brief

Thinx Super Absorbency Brief

Target

Why We Like It: It’s a basic design at a great value. Plus, they’re stretchy.

It’s Worth Noting: The gusset offers little coverage in the back, and it may not be as absorbent as advertised.

At $17 a pair, these period briefs from Thinx for All are some of the most affordable. Period products are notoriously expensive—even reusable ones, which save you money in the long run. You can expect to pay around $25 for most period underwear, so you’ll save roughly 30% when you go this route. But, don’t let “budget-friendly” scare you because these earned an overall rating on par with our best overall pick.

Our tester noticed that the gusset (the part that’s responsible for wicking moisture and absorbing period liquid) is thicker than others. This could explain why liquids “soaked in immediately.” However, it offers less coverage in the back. Our tester also noted that while it’s “very absorbent,” the absorbency may not be equivalent to five tampons’ worth. Still, the cotton feels nice and offers a surprising amount of stretch, which is nice since some period underwear feels stiff and tight. 

Editor's note: Thinx was part of a class-action settlement that alleged their products contain PFA chemicals. After speaking with experts, we still recommend Thinx products, but you can learn more about the settlement and PFAS in our "Your Questions, Answered" section below.

Price at time of publication: $17

Product Details:

  • Style: Brief
  • Material: Cotton, elastane
  • Size Range: XS–4X
  • Care Instructions: Machine wash cold and hang dry
  • Absorbency Level: 5 regular tampons
thinx brief period underwear test

Health / Leticia Almeida

Best for Comfort: Thinx Sleep Shorts

Thinx Period Sleep Shorts

Thinx

Why We Like It: The gusset padding offers a lot of coverage in the back, so you’re covered if you move around a lot in your sleep.

It’s Worth Noting: Though stylish and comfortable, they’re pricey.

Women experience all kinds of physical symptoms during their periods, so sometimes, all you want is to be comfortable. The nighttime can be especially tricky because period products can be uncomfortable or prone to leaking if you move around during your sleep. The Thinx Sleep Shorts solve both these common period problems. 

The short itself is made of micro modal, a breathable cotton alternative praised for its softness, and the built-in bikini underwear is mostly cotton. The multi-layer gusset offers a lot of coverage, and Thinx’s highest absorbency, making this period underwear perfect for overnight protection (or when you just want to relax on the couch).

During testing, our tester found that the “liquid disappeared immediately.” There was minimal transfer and some liquid showed up on the edges of the gusset, but the shorts remained dry. Our tester also loved the “super soft” material and the pockets, of course.

Editor's note: Thinx period underwear was the subject of a class-action settlement that stated their products contained chemicals known as PFAS. You can read more about PFAS in our "Your Questions, Answered" section below.

Price at time of publication: $50

Product Details:

  • Style: Pajama shorts with built-in bikini
  • Material: Cotton, spandex, polyester, micro modal, breathable PU
  • Size Range: XS–4X
  • Care Instructions: Delicate cycle and hang dry
  • Absorbency Level: 5 regular tampons

Best for Working Out: Thinx Cycle Shorts

Thinx Cycle Shorts

Amazon

Why We Like It: The material is so soft you’ll want to wear them even when it’s not that time of the month.

It’s Worth Noting: These work best as added protection with other period products, but may not offer enough protection on their own.

It’s totally okay to work out during your period, according to the U.S. Department of Health and Human Services' Office on Women’s Health. But, leakage is a valid concern for many. Whether your exercise of choice is a light walk or a sweaty gym session, the Thinx Cycling Shorts have built-in protection against leaks. 

On their own, they offer light protection—about two regular tampons’ worth. Our tester found that the liquid didn’t absorb immediately, leading to some noticeable dampness on the outside of the shorts. But, when teamed up with a tampon or cup, these would work nicely as an extra protective layer during physical activity.

Our tester appreciated the design and material of the shorts more than the absorbency. The shorts are “super soft” and “felt good” on the skin—so much so that our tester would happily wear these just for lounging. With a supportive waistband, mesh panels, and multiple pockets, they’re also thoughtfully designed for exercise. 

Editor's note: Thinx period underwear was part of a class-action settlement in 2022 that claimed their period underwear contained chemicals known as PFAS. You can read our "Your Questions, Answered" section below to learn more about PFAS in period underwear.

Price at time of publication: $75

Product Details:

  • Style: Bike Shorts
  • Material: Polyester, elastane, cotton, polyamide, and breathable PU
  • Size Range: XS–4X
  • Care Instructions: Delicate cycle and hang dry
  • Absorbency Level: 2 regular tampons
Thinx cycle shorts period underwear test

Health / Leticia Almeida

Best for Teens: Knix Leakproof Boyshort

Knix Leakproof Boyshort

Knix 

Why We Like It: No seams or tags make this a comfortable, smooth fit—like a “second skin.”

It’s Worth Noting: Liquids absorb quickly, but there’s significant transfer and noticeable dampness. 

When buying undergarments (period or regular underwear) the fit can be a deal breaker. Some period underwear has harsh seams and thick elastic bands that dig in, which isn’t exactly comfortable during an otherwise uncomfortable time. Our teen-friendly pick, the Knix Leakproof Boyshort, is so comfortable that our tester likened the “smooth and silky” fabric to a “second skin.”

Ultimately, the absorbency factor is also important when choosing period underwear, and this one is best for lighter flows or backup protection. It’s advertised as being able to absorb up to three teaspoons of liquid, but when put to the test, it didn’t pass with flying colors. Though the capacity wasn’t as high as we’d hoped, the liquid did absorb fairly quickly. For someone just learning the ropes of her monthly cycle, such as a teen or tween, this is a good place to start.

Price at time of publication: $22

Product Details:

  • Style: Boyshort
  • Material: Nylon, polyester, cotton, lycra, and carbon
  • Size Range: XS–4XL
  • Care Instructions: Machine wash on cold and lay flat to dry
  • Absorbency Level: 2 regular tampons
Knix Boyshort period underwear test

Leticia Almeida

Best for Heavy Flow: Dear Kate Ada Brief Full

Dear Kate Ada Brief Full
Dear Kate.

Why We Like It: It can hold more than the advertised capacity without leakage, making it suitable for heavier flows.

It’s Worth Noting: The exterior is super smooth, but the gusset is more rigid.

These period briefs are advertised as holding up to three teaspoons’ worth of liquids, but our tester found that the gusset can hold up to five. Our tester found no leaks or dampness on the outside of the gusset, earning this pair a perfect 5 for absorbency. While some period underwear should be reserved for your lighter days, these may be able to withstand heavier flows.

Our tester also approves of the design and feel. The absorbent material that makes up the gusset spans from the full front to the full back for leak-resistant protection, while the durable waistband keeps them in place. Our tester appreciated the “pretty” design and “silky soft” body. The texture of the gusset isn’t as smooth as the rest of the underwear, but our tester didn’t find it uncomfortable.

Price at time of publication: $46

Product Details:

  • Style: High-waisted brief
  • Material: Nylon, lycra, polyester, and elastane
  • Size Range: XS–3X
  • Care Instructions: Machine wash on cold and line dry
  • Absorbency Level: 2 regular tampons’ worth
Dear Kate period underwear test

Health / Leticia Almeida

Best Thong: Proof Leakproof Thong

Proof Leakproof Thong

Proof 

Why We Like It: The gusset is absorbent with little to no transfer, and the outside holds up well to spills. 

It’s Worth Noting: A period thong isn’t for everyone—the gusset has minimal coverage, and therefore minimal protection.

In the world of women’s underwear, there’s pretty much nothing more polarizing than thongs. Some can’t stand them, some can’t live without them. If you appreciate the lack of panty lines that a thong has to offer, you’ll gravitate towards the Proof thong with leakproof protection.

This thong offers all the benefits of a thong (by virtually eliminating panty lines) with the added protection of period underwear. It absorbed a teaspoon of liquid without seeping through to the outer layer. When our tester accidentally spilled liquid on the outer material, it also absorbed right in. Our tester also noted that despite the slightly rigid gusset, the underwear feels “soft and stretchy” with a seamless look. On days you need minimal protection without the harsh seams, this is an absorbent option.

Price at time of publication: $25

Product Details:

  • Style: Thong
  • Material: Nylon, spandex, cotton, polyester, and acrylate
  • Size Range: XS–3X
  • Care Instructions: Delicate cycle and hang dry
  • Absorbency Level: 1 regular tampon
Proof leakproof thong period underwear test

Health / Leticia Almeida

Best Lingerie-Style: Proof Leak Proof High Waisted Lace Brief

proof-leak-proof-high-waisted-lace-brief

Proof

Why We Like It: These briefs are both functional and stylish.

It’s Worth Noting: The lace adds breathability but could be perceived as scratchy by some.

Period underwear is designed to be functional, but these Proof briefs are proof they can be both functional and stylish. Wearing lingerie under your clothes can be a confidence booster, and you don’t have to miss out during your period. This pair of period underwear has a vintage design with lace cut-outs and a high waist. The fabric is stretchy and virtually seamless, so it’s comfortable and undetectable under your clothes. 

What’s more is its “impressive” level of absorbency, per our tester, thanks to an extended lining. The liquid absorbed pretty quickly, leaving the outside completely dry. There was an insignificant amount of transfer, so our tester dubbed them effective overall. Ultimately, our tester found them to be worth the investment, though some may find the lace scratchy against the skin.

Price at time of publication: $49

Product Details:

  • Style: High-waisted lace brief
  • Material: Nylon, spandex, cotton, polyester, and acrylate
  • Size Range: XS–XL
  • Care Instructions: Delicate cycle and hang dry
  • Absorbency Level: 3 regular tampons
Proof leakproof lace brief period underwear test

Health / Leticia Almeida

Best for Light Flow: AerieREAL Period™ Underwear

aeriereal-period-underwear

Aerie

Why We Like It: These have a simple design and are soft to the touch. 

It’s Worth Noting: Ideal for light to medium flows, these might not offer enough protection on their own.

These Aerie period underwear have a waistband that is “super stretchy,” according to our tester, so it won’t feel constrictive on your midsection. The entire underwear, including the gusset, is thick, which is ideal for absorbency but may not feel roomy under clothes. Our tester appreciated the gusset spanning the entire back of the underwear for protection, though there was some transfer, making these best for lighter flows.

This style also comes in fun prints and colors, which is a refreshing change when most options are black or nude.

Price at time of publication: $20

Product Details:

  • Style: Boybrief
  • Material: Cotton, acrylic, polyester, and elastane
  • Size Range: XXS–XXL
  • Care Instructions: Machine wash on delicate with cold water
  • Absorbency Level: 2 regular tampons
AerieREAL Period™ Underwear period underwear test

Health / Leticia Almeida

Best for Sleep: Goat Union Overnight Period Underwear

goat-union-overnight-period-underwear

Amazon

Why We Like It: With a front-to-rear extension, these are designed for overnight protection.

It’s Worth Noting: It has a lot of seams, which could dig in and cause discomfort.

It’s generally safe to sleep with a tampon, but it should never be worn for more than eight hours at a time, according to the Food & Drug Administration. So, period underwear is a great nighttime alternative to tampons if you need your beauty sleep free from the worry of toxic shock syndrome.

Goat Union designs period underwear specifically for sleep. Each pair is constructed with a wide gusset, offering extended protection in the front and back. When put to the test, our tester found that the gusset did absorb liquid, but did so at a slow rate, so you may feel some dampness in the gusset at times. Moisture didn’t seep through to the outside, so you don’t have to worry about overnight leakage.

At $17, our tester found these to be a great value but had some reservations about the design. The mesh panel at the waist creates a lot of seams, which “didn’t feel great.” Fortunately, the rest of the underwear is “thick and soft.”

Price at time of publication: $17

Product Details:

  • Style: Briefs
  • Material: Cotton, spandex, polyester, nylon, and bamboo
  • Size Range: XS–4XL
  • Care Instructions: Gentle cycle and hang or low tumble dry
  • Absorbency Level: 3-4 regular tampons
Goat Union period underwear test

Health / Leticia Almeida

Best High Waisted: Saalt Leakproof High Waist Brief

saalt-leakproof-high-waist

Saalt

Why We Like It: Designed in Paris, these look and feel luxurious.

It’s Worth Noting: Elegant as they are, they’re not as absorbent or protective as some of the others we tested.

If you’re looking for the best design, look no further. Saalt period underwear is designed in Paris, bringing a sense of luxury and elegance to period products. Our tester found these to be the “most luxurious” of the lot with “unique” details that make them stand out from the rest. Made from recycled water bottles, you wouldn’t expect these to be so “soft and stretchy,” per our tester, who also appreciated the "modern" pattern.

Functionally, these may be best for lighter flows. They absorbed liquid quickly, but there was a small amount of leakage and transfer, per our tester. The gusset doesn’t extend as far back as other options, which may not block leakage. 

Price at time of publication: $39

Product Details:

  • Style: High-waisted briefs
  • Material: Recycled polyester and elastane
  • Size Range: XS–XXL
  • Care Instructions: Rinse in cold water, machine wash on cold, and hang dry
  • Absorbency Level: 3 regular tampons
saalt leakproof period underwear test

Health / Leticia Almeida

Best for Plus Sizes: TomboyX First Line Leakproof Bikini

Tomboy X First Line Leakproof Bikini

Tomboy X

Why We Like It: Extended sizing makes period underwear accessible to those outside the standard size range.

It’s Worth Noting: It may not hold as much liquid as advertised.

Period underwear typically comes in sizes XS to 4X, but this may not accommodate everyone. For extended sizes, TomboyX has you covered. The inclusive size range spans from 3XS to 6X, making period underwear more accessible if size is a constraint at other brands.

Our tester also liked the “sporty” design, making note of the thick waistband that wouldn’t roll down during sleep or exercise. There is some concern in the absorbency department, however. Though TomboyX claims its underwear can hold up to eight teaspoons of liquid, our tester found it was “sopping” wet with just six teaspoons. At smaller capacities, our tester noted it “absorbed very quickly” and left the underwear “bone dry.” 

Price at time of publication: $25

Product Details:

  • Style: Bikini
  • Material: Cotton, spandex, and polyester
  • Size Range: 3XS–6X
  • Care Instructions: Machine wash on cold and line dry
  • Absorbency Level: Up to 6 teaspoons
TOMBOYX first line leakproof bikini period underwear test

Health / Leticia Almeida

Best Seamless: The Eco Woman Period Panties

The Eco Woman EcoPanties Seamless

The Eco Woman

Why We Like It: Our tester was blown away by the soft fabric, superb absorbency, and affordability—all without protruding seams.

It’s Worth Noting: The manufacturer recommends soaking them in cold water before machine washing, which is an added step in the care process.

Our testers have likened some period underwear to wearing a diaper, but that is not the case with The Eco Woman. They are “buttery soft” and have flat seams so they don’t protrude, according to our tester. The gusset has a unique triangle shape that gives it solid coverage from front to back without being obtrusive.

Functionally, our tester said these are “unlike any of the others” since they “easily absorbed” four teaspoons of liquid. There was slight dampness in the gusset, but the interior seams were mostly dry while the exterior was completely dry. The secret, according to The Eco Woman, is a super absorbent layer that absorbs 12 times its weight in three seconds and distributes the liquids evenly.

Even with the affordable price, our tester found these just as effective as other options.

Price at time of publication: $20

Product Details:

  • Style: Briefs
  • Material: Cotton, lycra, polyester, and waterproof PUL
  • Size Range: XS–XXXL
  • Care Instructions: Soak in cold water, machine wash on cold, and hang dry
  • Absorbency Level: 3 times more than a tampon and up to 3 times that of a disposable pad
Eco Woman period underwear test

Health / Leticia Almeida

Our Testing Process

The following testing procedure was followed with expert input from Adi Katz, MD, FACOG, the director of gynecology and director for the obstetrics and gynecology residency program at Lenox Hill Hospital, and Susan S. Khalil, MD, director of the Division of Sexual Health in Obstetrics, Gynecology, and Reproductive Science at the Icahn School of Medicine at Mount Sinai.

Testers created a liquid solution with apple cider vinegar (for scent) and food coloring (for stains). Testers poured one teaspoon to eight teaspoons (depending on the product’s advertised absorbency) of the mixture on each pair of underwear. 

The tester then noted things like how quickly the liquid was absorbed, if there was any transfer, the softness of the fabric, and the overall value for the price.

Period Underwear Tests

Health / Leticia Almeida

What to Know About Period Underwear

How Period Underwear Works

Period underwear works by absorbing menstrual liquids. Unlike menstrual cups and discs, which collect liquids, menstrual underwear is made with absorbent, moisture-wicking fabrics that soak up period blood to a designated layer while keeping the outer layers dry. 

“Period underwear works,” explains Dr. Goodall McDonald. “Period underwear is made from material that is very absorbent and able to hold the standard 30–80 cubic centimeters of blood.”

It’s all in the material and gusset. A gusset is an extra piece of fabric commonly found in the crotch of your underwear. It enlarges an area of fabric, reinforcing it and giving it stretch. In period underwear, the gusset is where the absorbent materials are used. Period underwear usually has a 3- or 4-layer gusset with the innermost layers absorbing period liquids and the outermost layers preventing leakage and staying dry.

Natasha Spencer, MD, an obstetrician and gynecologist with Orlando Health Physician Associates, explains how period underwear works: “The inner layer is designed to wick moisture away from the body and usually has a water-repellant finish to push fluid through multiple channels. The middle layer is super absorbent and locks fluid inside. The outer layer is water impermeable, preventing liquid from leaking through the middle layer and onto clothing.”

How to Wash Period Underwear

Care instructions for period underwear can vary based on the manufacturer’s recommendations. Rather than letting them pile up in your laundry basket, you should wash your period underwear as soon as you’ve used them.

Most period underwear is machine washable on cold, delicate, or gentle cycles. Some manufacturers recommend rinsing or soaking period underwear before placing them in the washer with your other clothes. For further protection, use a mesh or garment bag to keep them separate from your other clothes.

To preserve their quality, stick to gentle soaps and mild detergents. Harsh detergents and bleach can cause discoloration. Dry your period underwear on a line or flat surface so they retain their shape. However, some period underwear can be tumble dried on low.

Materials to Look for in Period Underwear

The materials used to make period underwear are what give them their absorbent properties. The period underwear we tested are mostly made from cotton, polyester, nylon, and elastane. Cotton is the best material since it’s breathable, according to the gynecologists we spoke to.

“Period underwear typically contains cotton, which is comfortable and breathable, and some kind of spandex that gives them stretch,” says Stephanie Hack, MD, FACOG, a board-certified obstetrician and gynecologist with a special interest in women’s health advocacy.

The materials that work best for you may also come down to personal preference and flow. “When made properly, all period underwear is effective and comfortable,” says Dr. Spencer. “Certain materials, such as nylon and cotton, in the outer layer may be more comfortable, however.”

Materials to Avoid When Shopping for Period Underwear

Period underwear, when made and used properly, are relatively safe. “The only concerns are making sure you are not allergic to the materials, that you are washing them properly to allow them to be effective and durable, and not wearing them longer than recommended,” Dr. Hack says.

Avoiding certain materials and designs can come down to personal preference. Some of our testers found materials like lace details and mesh panels to be scratchy and uncomfortable. Others didn’t like the overuse of elastic waistbands, which can dig in and cause discomfort.

What you can expect to pay for period underwear

The period underwear we tested ranged in price from $10 to $50. Some period-friendly clothes with built-in period underwear, such as biker shorts and leggings, can run you upwards of $75 to $95. The median price, we found, is $25 per pair of period underwear.

More Period Underwear to Consider

While these products didn’t live up to our expectations enough for us to recommend them, they may still be of interest to you. 

  • Thinx Leggings: Leggings are a closet staple, but many women may feel too restricted to wear them during their periods. The Thinx Leggings have built-in period underwear designed to prevent leaking during that time of the month, allowing you to lounge, run errands, exercise, or just live your life without worry. However, they may not live up to the hype. Our tester found some issues with leakage. At the steep price, it’s not worth the risk, even though they have tons of pockets.
  • Bambody Absorbent High Waist Comfy Fit Period Underwear: The bamboo material is soft and stretchy, so the fit is as advertised—they’re comfortable. However, our tester wasn’t a fan of the bamboo material and found issues with leakage. The poor absorbency may be due to the bamboo material or the small gusset size.
  • Knix Leakproof Thong: For light flows, a period thong could come in handy. Our tester liked the “ridiculously soft” and seamless fabric and was very surprised with how absorbent it was. Though the gusset absorbed all the liquid and managed to stay dry on the outside, our tester wasn’t sure of the value at the price point.
  • Aisle Leakproof BOOST Boxer: The brand claims this period boxer can hold over eight tampons worth of liquid, but our tester came to a different conclusion. It soaked up eight teaspoons fairly quickly (but not immediately) without any leakage. Our tester wanted to recommend them for the high absorbency but not at the price given the uniqueness of the design.
  • Rael Reusable Period underwear: This budget-friendly pick is great for those looking for a mostly cotton option since cotton is very breathable and comfortable. The drawbacks our tester found, however, were the lack of stretch and questionable quality since the layers separated from the gusset easily.
Bambody hipster sporty panties period underwear tests

Health / Leticia Almeida

Your Questions, Answered

How concerned should I be about PFAS in period underwear?

Polyfluoroalkyl substances (PFAS) are used in a wide variety of products to make them non-stick, grease-resistant, and waterproof. "PFAS are likely used in period underwear to provide a waterproof barrier between the underwear and skin," says Kelly Johnson-Arbor, MD, FACEP, FUHM, FACMT, Medical Toxicologist, Co-Medical Director, and Interim Executive Director of the National Capital Poison Center.

After a class-action settlement by Thinx that pertains to allegations made about the presence of (PFAS) in their period underwear, many people who use period underwear wonder if PFAS should be a concern, but the exact health significance of these products, when used on period underwear, remains unclear. "The true effect of PFAS exposure on female reproductive health remains unknown," says Dr. Johnson-Arbor. She adds that all people are exposed to PFAS daily and avoiding these compounds is virtually impossible.

"I would caution against knee-jerk reactions since there are a lot about PFAS we don't know, including how much can be absorbed through the skin. For some people, period underwear may be an important part of their period care. Personally, I'm not getting rid of my period underwear, and I'm more concerned with ways in which we are ingesting PFAS," Staci Tanouye, MD, a practicing OBGYN in Jacksonville, FL, tells Health.

Because period products are unregulated by the Food & Drug Administration (FDA), there are currently no definitive ways for consumers to know if the period underwear or menstrual products they use contain PFAS.

Does period underwear actually work?

A pair of panties that magically soaks up your period blood may seem too good to be true, but it’s not. Period underwear actually work. “Yes, period underwear work in the capacity that they are expected to work,” Dr. Spencer says. They’re made with a thick gusset that has highly absorbent inner layers to soak up liquids while moisture-wicking outer layers work to stay dry.

Do period underwear smell?

Any garment, if not cared for properly, can develop an odor. Period underwear is no different—you’ll want to change them frequently and wash them immediately after each use to prevent odor-causing bacteria from growing. Some period underwear is made with antimicrobial layers. “This means that it resists bacterial growth, so it is sanitary and will not create a smell,” says Dr. Goodall McDonald.

“Period underwear are sanitary and typically have substances in the absorbent layer that eliminates odor,” says Dr. Spencer. “They can possibly develop a smell after a multitude of uses and if they’re not cleaned properly.”

Do you just wash period underwear?

The care instructions for period underwear depend on the manufacturer. For most, you should rinse them under cold running water, wash them in cold water on a delicate cycle, and hang or lay them flat to dry. Stick with mild detergents to prevent discoloration.

Can you bleed through period underwear?

Bleeding through period underwear is possible depending on your flow and the absorbency level of the underwear. However, this is largely preventable by following the instructions on the period underwear based on the level of your flow. It’s even more unlikely if you use period underwear as backup protection to tampons and menstrual cups. ”If a person passes a fair amount of blood clots or has a high volume flow, they run the risk of overflow,” Dr. Goodall McDonald explains. Ill-fitting period underwear could also lead to leakage.

Who We Are

Lacey Muinos is a health and wellness writer who masters a variety of topics from acne treatments to women’s health and more. She has personally tested and reported on a variety of products, such as air fryers and moisturizers. Between in-depth research and expert interviews, she’s a pro at finding information and getting it in front of the people who need it most.

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