We’re quick to spill details on our favorite lacy thongs and seamless underwear that actually remain hidden under our workout leggings, But period underwear rarely comes up in conversation, and quite frankly we think that should change, because period panties, which absorb blood using moisture-wicking fabrics, are game changers. The washable reusable undergarments ditch the amount of waste we create from disposable products, can hold more blood than regular tampons, and certain styles are significantly more comfortable than other feminine products. The result? Peace of mind and time back in our days. Beyond that, brands offer them in nearly every style, including boxers, briefs, and even thongs (yes, really), so there are options for every situation and every type of flow.
That said, between the different types of silhouettes, fabrics, and absorbency levels to choose from, exploring this option will look a little different for everyone. To find the best ones for your individual experience, we sent 46 pairs of the most popular period underwear to our New York City-based testing lab and we tested them by simulating real-world situations using teaspoons of water and filter paper. From there we assessed each pair of panties based on how much liquid they held before leaking, whether the material was soft and breathable, and durability (did they hold up after washing?). Then, we consulted two board-certified gynecologists and a nurse practitioner to answer every question about how period panties work and what to consider before purchasing a pair.
We’ve seen the recent allegations and lawsuit settlement with Thinx that claims the brand’s organic cotton underwear contains per- and polyfluoroalkyl substances (also known as PFAS), which have been linked to various health concerns, like cancer, and Agion antimicrobial treatment. Thinx denies these allegations and does not admit wrongdoing.
We are currently conducting research by interviewing experts to educate ourselves on the topic and will update this story with further information. In the meantime, we do recommend Thinx within this story; however, we also suggest 13 other options for you to shop from different brands.
Thinx For All Super Absorbency Brief
What We Love: We could wear the thick, comfy fabric all day and never feel uncomfortable.
What We Don’t Love: These run on the small side.
Instantly we could tell by its cushiony cotton fabric and thick gusset, which felt similar to a soft washcloth, the Thinx For All Super Absorbency Brief would remain secure and comfortable through even the heaviest flows. Additionally, it held up to four teaspoons of fluid, about four tampons worth, which is an impressive amount considering costs less than its competitors.
Sure, the fabric is a tad bulkier than your average panty, but we appreciated that it hugged close to our silhouette for extra security and support. That said, you may find this tighter fit means you need to size up. On that note, the brand offers the underwear in sizes up to 4X — a win for size inclusivity.
Absorbency: Heavy | Size: XS–4X | Material: Cotton, spandex | Colors: 4
AerieREAL Period Underwear
What We Love: They’re an affordable option that works great for light to medium flow days.
What We Don’t Love: The gusset reaches to the back of the underwear and could feel diaper-like to some wearers.
We’re thrilled Aerie’s period underwear lives up to the same standards as its comfortable bras and underwear we wear everywhere, and at the affordable price, we’ve come to expect from the intimates brand too. The period underwear features a super stretchy, non-constricting waistband and panty line, and breathable, buttery soft jersey fabric that’s comfortable to sit, walk and play in, especially with the extra support the extended gusset provides. Though depending on your preference some wearers may find this design detail to have a diaper-adjacent feel, but it didn’t bother us. However, either way, we’ll likely save this underwear for wearing around the house or near the end of our cycle when our flow is lighter because it wasn’t the most absorbent option we tried.
Absorbency: Light to medium | Size: XXS–XXL | Material: Cotton, acrylic, polyester, elastane | Colors: 7
Proof Leak Proof High Waisted Lace Brief
What We Love: For being a more stylistic choice, we were very impressed by how well they absorbed fluid.
What We Don’t Love: The structured waistband doesn’t have much give for bloating.
Yes, period underwear can be functional and stylish. These panties are well worth the price tag simply because their chic look allows you to wear them on and off your period. They feature silky fabric, a cheeky fit, and breathable lace mesh inserts, dashing any of our preconceived notions that period underwear is strictly utilitarian. Despite their deceptively delicate appearance, they were ultra-absorbent. Seriously, we wouldn’t be afraid to wear them during our heaviest flows, but we’d skip them on days we’re prone to bloating because the waistband isn’t very stretchy.
Absorbency: Medium | Size: XS–XL | Material: Polyester, spandex, nylon | Colors: 1
Knix Leakproof Thong
What We Love: The skimpy silhouette was surprisingly absorbent, and it felt secure and more comfortable than a traditional thong.
What We Don’t Love: They are better saved for lighter flows.
As much as we love how the best thongs prevent VPLS, the phrase “period thong,” doesn’t inspire much confidence in us, but the Knix Leakproof Thong exceeded our expectations. The panties quickly absorbed liquid, the outer gusset stayed completely dry, and we saw no spillover. Though we probably wouldn’t risk wearing it during the first couple of days of our cycle, its seamless design makes it a great backup option if we want to wear tighter-fitting clothing, like say for a special event, and don’t have enough confidence in a pad or tampon alone. Additionally, between the 10 sophisticated modish shades to choose from and smooth, velvety fabric, these panties are luxe enough to double as everyday underwear.
Absorbency: Light | Size: XS–4X | Material: Cotton, spandex, nylon | Colors: 17
Cora Period Underwear
What We Love: These bikini-style panties give you the look and feel of regular, everyday underwear.
What We Don’t Love: The gusset isn’t full-coverage.
Being on our cycle is uncomfortable enough without our underwear reminding us that it’s there every five seconds, which is why we’re thankful Cora Period Underwear provides a comfortable bikini-cut option that disguises itself under clothing. The breathable 100 percent cotton fabric provides plenty of airflow for a fresh feel, and its firm elastic waistband sits snug and secure against our bodies, while still having plenty of give for the inevitable bloating. The best part? The gusset still felt dry holding up to three tampons worth of fluid, making it a great contender for heavier flows. Keep in mind this underwear style provides a little less coverage than other options, but it does remain discreet every time we wear tighter jeans and skirts.
Absorbency: Medium | Size: XS–XXL | Material: Cotton | Colors: 1
Saalt Leakproof High Waist
What We Love: These Saalt briefs boast an elegant style, challenging what we think when we hear the words “period underwear.”
What We Don’t Love: The ribbed gusset stops a bit short in the back, leaving you susceptible to potential leakage.
The Saalt Leakproof High Waist Brief is part shapewear, part lingerie. Let us explain: The intricate mesh design inset and silky fabric elevated the look and feel of the panties, while its high-rise fit smoothed our silhouette for a flattering finish. And, the stretchy material is not only a huge plus for days we’re bloated but it feels extremely lightweight so we could hardly tell we were wearing underwear at all. Better yet, we can wear them during heavy flows because they performed as promised and absorbed three regular tampons worth of liquid. If we could change one thing, however, we’d extend the gusset further up the back because we might experience leakage with its shorter design.
Absorbency: Medium | Size: XS–XXL | Material: Recycled Polyester | Colors: 2
Thinx Sleep Shorts
What We Love: Between the full-coverage design and absorbent material, these super-absorbent sleep shorts allow us to rest easy.
What We Don’t Love: We wish the built-in underwear was an extended boy short instead of hipster style.
Aside from the fact that they’re having a bit of a sartorial moment (hi, Blake Lively), boxers are an ideal choice for period underwear, especially if you want to avoid nighttime leakage and especially if you’re wearing the lightweight, comfortable, and high-coverage Thinx Sleep Shorts. In addition to adorable design details like pockets and decorative buttons, we also appreciated that even fitful sleepers need not fret about wearing these to bed because the padded gusset extends high up the front and back for extra assurance.
In fact, they’re so stretchy and soft, that we’d even recommend them to postpartum mothers as an alternative to more constrictive adult underwear. We wouldn’t mind if the built-in underwear was a boy short silhouette over the hipster cut, but we still found this design provided plenty of coverage.
Absorbency: Super | Size: XS–4XL | Material: Cotton, polyester, elastane, modal | Colors: 3
Dear Kate Ada Full Brief
What We Love: No longer do we need to worry about our period ruining our nice underwear — this lacey little number is fashionable and still absorbs liquid quickly.
What We Don’t Love: The tag is inconveniently located on a side seam and can feel aggravating.
Don’t mistake this little lacey number for a purely aesthetics-driven purchase, though the high-rise fit and neatly bordered hemline (which is far more durable than it looks) does lend it a charming look. More importantly, thanks to its three-layer gusset and moisture-wicking fabric, the Dear Kate Ada Brief was one of the most absorbent options we tested. It managed to hold five teaspoons of liquid without leaking and it remained dry as a bone on the outside. We’d just recommend cutting out the tag that’s located on the side seam–its awkward placement bugged us. But other than this easy fix we adored everything about this pair of underwear.
Absorbency: Medium to Heavy | Size: XS–3XL | Material: Nylon, polyester, elastane | Colors: 3
The Eco Woman Seamless EcoPanties
What We Love: It’s hard to find a great pair of seamless panties — let alone ones capable of period protection — but these are foolproof.
What We Don’t Love: This pair requires soaking in cold water for 30 minutes, which adds an extra step to the washing process.
Seamless underwear is a tricky friend — on one hand, we love how the design keeps VPLs in check, but on the other, they often lack grip and are constantly (infuriatingly so) slipping down. However, the Eco Woman panties and their invisible stitching lay truly flat on our bodies and look hidden under body-skimming clothing — all while feeling dry holding four teaspoons of liquid. The extended gusset provided extra reinforcement too and made the entire design feel less diaper-adjacent (IYKYK). One thing to note: Caring for this pair requires a little extra time and maintenance as you have to soak them in cold water before sticking them in the wash.
Absorbency: Medium to Heavy | Size: S–4XL | Material: Cotton | Colors: 3
Best for Light Flows
Thinx Air Hiphugger Period Underwear
What We Love: The moisture-wicking, lightweight mesh material is ideal for workouts and summer days.
What We Don’t Love: They’re better as a backup option than a standalone one for anyone who has medium to heavier flows.
If your flow is light (lucky you) or tends to peter out towards the end of your cycle, this thin pair of hip-hugging Thinx panties provide just the right amount of lightweight coverage to get you over the finish line dry and secure. Unlike some of the thick, claustrophobic, and bulky silhouettes we tried, Thinx designs these panties with breathable micromesh fabric perfect for hot days or workouts. Seriously, we could do cartwheels in these little panties. Despite its paper-weight design, the gusset extends high and wide enough that we felt pretty confident we could avoid spillage on a lighter day. Would we use them as a first line of defense when our flow is particularly heavy? Hard to say, but they’re a reliable backup option. Additionally, we love how the flat elastic seams don’t fold over, an aggravating pain point for any kind of underwear.
Absorbency: Light | Size: XS–4XL | Material: Nylon, elastane | Colors: 4
Best for Heavy Flows
Knix Cotton Modal Super Absorbency Leakproof Bikini
What We Love: These undies held an impressive amount of fluid while still feeling flexible and comfy to wear.
What We Don’t Love: The silhouette is a little bulky.
Imagine a world where you never had to think about, look at, or touch a tampon again. Yeah, the Knix Cotton Leakproof Bikini brief is that good at keeping spillage in check. We doused these panties in eight brimming teaspoons of liquid and there wasn’t a leak in sight. Sure, it’s not the most discreet option we tried (the gusset is pretty thick), but the bulkier fit is a tradeoff we’re more than happy to make in exchange for the peace of mind wearing these extremely absorbent underwear provides. Plus we found that the panties flexed with our movements rather than feeling stiff and immobile, and would be the perfect plus one for our workouts.
Absorbency: Heavy | Size: XS–4XL | Material: Cotton, modal, spandex, polyester | Colors: 7
Best for Plus Sizes
TomboyX First Line Leakproof Bikini
What We Love: The company utilizes OEKO-TEX Certified materials that are free from toxins like PFOS or PFOA chemicals.
What We Don’t Love: They weren’t as absorbent as we expected.
Though the fashion industry still has room to improve, we’re finally seeing some movement in brands offering plus-size underwear, and thankfully this extends to period undies as well. TOMBOYX offers its sporty Leakproof Bikini panties in sizes up to 6XL and incorporates other thoughtful design details like a thick band that keeps the panties securely around our waist, particularly while we sleep, and a flexible gusset. Additionally, the brand only uses OEKO-TEX Certified materials that are guaranteed free from harmful cancer and infertility-causing chemicals, so we can feel better about our purchase. On the downside is the brand promised they’d hold up to eight teaspoons of liquid and they started to feel soaked after six, but depending on your flow this could still be enough coverage.
Absorbency: Medium | Size: 3XS–6X | Material: Cotton, polyester, spandex | Colors: 9
Aisle Leakproof BOOST Boxer Short
What We Love: There’s a pocket inside the gusset to place a pad.
What We Don’t Love: The silhouette may not be discreet enough for everyday wear.
Frankly put, the Aisle Leakproof Boxer may not be on par with your best lingerie or sultry La Perla panties, but they get the job done and their full-coverage fit eases our anxieties around leakage. And what’s sexier than a calm mind? The fabric quickly absorbs up to eight teaspoons of liquid, around five regular tampons, and has extra space in the gusset to slip a pad into for further reinforcement, saving us from swapping out our tampon or pad in the middle of the day. Additionally, a thick waistband keeps the undies firmly in place no matter how much we move. That said, this style isn’t the most versatile option since its longer length and bulkier silhouette may peek out under shorter skirts or show beneath thinner fabrics, but they will be our go-to for lounging and sleeping.
Absorbency: Heavy | Size: XXS–5XL | Material: Tencel, cotton, spandex, polyester | Colors: 3
Goat Union Overnight Period Shorts
What We Love: The high-rise fit stays put while we snooze and its full coverage design ensures zero leakage.
What We Don’t Love: We’ve tried softer options.
Even given our luxurious silk pillowcases, we have a lot of roadblocks standing between us and a good night’s rest (doom-scrolling on TikTok for one) but finally, our period won’t be one of them. Because the Goat Union Overnight Shorts hold about six teaspoons of liquid, we can already imagine our sound uninterrupted sleep — one where we’re not waking up at 3 a.m. to change an overflowing pad or tampon. We also appreciate the high-rise fit and firm waistband that allows us to toss and turn all night without yanking up our underwear mid-snooze. And, although the viscose material didn’t feel quite as plush as cotton, it still felt smooth, and non-irritating enough for sleeping and lounging.
Absorbency: Heavy | Size: XXS–6XL | Material: Cotton, spandex, polyester, nylon | Colors: 1
Our Testing Process
For this story, 46 pairs of period underwear were put to the ultimate tests of absorption, comfort, and fit in our testing lab. Meanwhile, double board-certified gynecologist Dr. Monica Grover, Family Nurse Practitioner in Dermatology Dr. Jodi LoGerfo, and “Lady Parts Doctor” podcast host Dr. Stephanie Hack all contributed expert commentary and wellness knowledge.
What to Keep in Mind
- Absorbency: Since your flow rarely stays consistent throughout your cycle, “It’s important to pick products with multiple absorbances to match your flow as it changes,” says Dr. Hack, a board-certified obstetrician and gynecologist. In the same way that tampons and pads advertise whether they’re suitable for a light, medium, or heavy flow, period underwear offers similar guidelines and typically states how absorbent they are related to how many tampons-worth of liquid they hold. But, honestly, it may take some trial and error until you find the best fit for your flow, so if this is your first time free bleeding it’s not a bad idea to keep a tampon or pad on hand.
- Fit and Silhouette: Period underwear comes in the same styles and cut as our regular, everyday panties, so you have the option to choose the silhouette you’re most comfortable wearing, whether that’s an itty bitty thong or full-coverage briefs. Still, we recommend considering where you’ll be wearing them and what activities you’re performing. For instance, boxers are a great choice for sleeping, lounging, and working out because they provide the most coverage, but might look awkward and bulky under formal clothing. On the other hand, though their slimmer silhouettes make them more susceptible to spillage, bikini-cut panties, and thongs allow more freedom in the types of pants and skirts you wear with them.
- Material: When possible, it’s best to seek out organic and hypoallergenic materials free from toxic chemicals. “I recommend looking for certified labels, such as OEKO-TEX, which verifies that every fiber in the garment has been tested for harmful substances,” advises Dr. Grover. Additionally, Dr. LoGerfo says, “I always recommend consulting with a professional in the medical field when there are concerns about how your skin will interact with certain chemicals,” adding that because everyone’s skin is different, one person’s interaction will not be the same as someone else’s.
Your Questions, Answered
How does period underwear work?
Period underwear should fit and feel like your everyday panties, except they’re equipped with extra layers of absorbent and moisture-wicking fabric to prevent leakage. They often use breathable materials like cotton for odor control and polyester or nylon to trap liquid and stop it from staining clothes.
How do you clean period panties?
One of the best parts of period panties? They’re reusable and usually require no extra effort to clean than your other intimates — just follow the manufacturer’s instructions. You can simply toss some styles in the wash and let the cycle run, but others may require you to hand wash or rinse ahead of placing them in your machine.
Are period underwear sanitary?
“Absolutely, as long as you wash them after each use to ensure they’re hygienic and safe for you to wear,” says Dr. Grover. For proper hygiene, Dr. LoGerfo adds, “They should be changed at least every 12 hours or more often if needed.”
Should you be concerned about period underwear possibly containing PFAS or “forever chemicals”?
According to Dr. LoGerfo, PFAS stands for per- and polyfluoroalkyl substances, which are a group of chemicals often referred to as “forever chemicals” because they’re nearly indestructible. “PFAS can enter the body multiple ways, including through the nose, mouth, and skin,” she explains.
“Certain levels of PFAS have been associated with negative effects on reproductive health (decreased fertility), hormone disruption, an increased risk of certain cancers, and developmental delays in children, among other things. The vaginal mucosa is absorbent, and may readily absorb these chemicals,” she says.
However, research is still ongoing and there isn’t enough evidence to confirm the level of exposure that will lead to these adverse effects. And though some period underwear brands utilize PFAS in their materials (like Thinx), the unfortunate reality is that many consumer goods from cosmetics to tampons contain PFAS, according to Dr. Hack.
Why Shop With Us
Irene Richardson updated this article. She is a fashion and beauty commerce writer for InStyle.
Linne Halpern is a freelance beauty, fashion, and lifestyle writer. She is a member of InStyle’s evergreen commerce team where she extensively researches and reviews countless products.
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