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The Best Period Underwear, Tested in Our Labs
Shop the most absorbent and affordable period panties for your flow.
We reviewed this guide to ensure all information and shopping links are accurate in May 2023.
If you're looking to cut back on waste, period panties can be a sustainable and cost-effective alternative to disposable menstrual products like pads, tampons and liners. The best period underwear looks and fits just like regular underwear, but features a special layer that helps prevent blood from leaking through.
While there are now plenty of stylish and comfortable options available, you'll want to steer clear of any styles that aren't absorbent enough or add unnecessary bulk. To find the best period underwear, the Good Housekeeping Institute Textiles Lab checked the absorbency of top-rated pairs using red cough syrup (manufacturers use it to test pads and tampons too!) and also sent home 17 different styles with 85 testers to get feedback on comfort, leaks and more. We reviewed over 1,500 data points before making our recommendations.
Our top-tested picks:
If you're new to wearing period underwear, one word of caution: In our Lab tests, we found that even the most effective styles couldn't absorb the cough syrup as well as traditional pads. So if you have a heavy flow, you may want to stick to wearing period underwear just as a backup to a menstrual cup or other disposable menstrual supplies.
Keep reading to shop our top-performing picks, and find more information about period underwear materials, safety and sustainability at the bottom of this guide. Looking for more ways to improve your period experience? Check out our top picks for the best period swimwear and the best heating pads to soothe cramps.
Knix Leakproof Bikini
Pros
- Nude color options
- Breathable, lightweight materials
- Top-performing absorbency without a bulky pad
Cons
- Not designed for heavy flow days or overnight protection
For a barely there feel, testers raved about this pair's breathable nylon/Lycra material that felt just like regular underwear with a cotton gusset. This style is available in five nude shades to match a variety of skin tones, plus there are even more fun color and pattern options, too.
• Lab results: Soaking up liquid easily at various angles, this pair aced all Lab evaluations with no signs of wear after laundering multiple times. GH analysts appreciated the lightweight fabric similar to athletic wear that stays hidden under clothes — no more panty lines.
• Tester notes: Testers were impressed how thin the pad was, agreeing that these are the "perfect back-up to tampons on heavier flow days" and ideal for lighter days on their own. One raved that they were "the most comfortable period underwear I've ever tried."
| Absorbency | Light coverage (3 tsp fluid) |
|---|---|
| Sizing | XS–XXXXL |
| Care instructions | Machine wash cold and lay flat to dry. |
| Body material | 77% nylon, 23% Lycra Xtra Life |
| Gusset material | 86% cotton, 10% spandex, 4% carbon with inner 100% polyester layer |
| Return policy | Free returns within 30 days; can be worn and washed. |
Thinx Hiphugger Menstrual Underwear
Pros
- Thousands of rave reviews online
- Original brand to develop the period underwear industry
- Easily absorbed and held onto fluid in Lab evaluations
Cons
- Some testers found them too tight and constrictive
Thinx is probably the most popular brand on this list, and that's for two good reasons: 1) Its marketing campaigns are everywhere and 2) Our testers love the product. One person thought they would never find period panties that were stylish, comfortable and functional — until they tested out a pair of Thinx.
• Lab results: The absorbent core quickly absorbed fluid with only minimal runoff when applied at an angle. They showed no signs of wear after laundering with the mesh detailing staying in prime condition.
• Tester notes: One tester said this pair was "absorbent and didn't leak at all." However, some testers noted that the band was a bit snug.
Take note: Thinx recently settled a class action lawsuit claiming its underwear contains man-made "forever chemicals" per- and polyfluoroalkyl substances (PFAS), though the brand denies these claims. Get more information on the settlement here.
| Absorbency | Moderate (3 tampons' fluid) |
|---|---|
| Sizing | XS–4X |
| Care instructions | Machine wash cold and lay flat to dry. |
| Body material | 84% polyamide, 16% elastane |
| Gusset material | 95% cotton, 5% elastane |
| Return policy | Free returns within 30 days on Amazon in new and unused condition. |
TomboyX First Line Period Bikini
TomboyX First Line Period Bikini
Pros
- Excellent range of sizes
- Absorbed all the fluid in our tests without leaking
- Longer pad for full coverage
Cons
- Bulkier fit, according to some testers
This style from TomboyX has the most size options — from 3XS to 6XL — out of all the styles tested. Our pros love that this brand features a variety of gender neutral options too.
• Lab results: With a longer liner and wide waistband, these skivvies stayed in place securely and absorbed fluid quickly in our tests. GH analysts also note that the full coverage design would also be great to use as overnight protection.
• Tester notes: Made with a cotton/spandex blend, testers said the "fabric was super soft." While testers did note this option was visible under some clothing items, they especially appreciated its high absorbency when worn at home or overnight.
| Absorbency | Heavy coverage (8 tsp fluid) |
|---|---|
| Sizing | 3XS–6XL |
| Care instructions | Machine wash cold in a mesh bag, line dry overnight. Avoid machine drying. |
| Body material | 95% cotton, 5% spandex |
| Gusset material | 89% polyester, 11% spandex |
| Return policy | Free returns for used first-time underwear orders from TomboyX; future orders can be returned unused and unwashed within 30 days. |
KT by Knix Starter Set
KT by Knix Starter Set
Pros
- Three underwear options included
- Moderate to full overnight coverage
Cons
- Available only in black
Your first period can be exciting but scary too. KT by Knix provides comfy options that can make the new stage easier for tweens. This starter set includes the brand's original leakproof style, a super absorbent option and sleep shorts. For the two underwear styles, you can choose between bikini and boyshort too.
• Lab results: The brand's original leakproof underwear aced Lab evaluations for quickly absorbing fluid at a variety of angles without leaking. The sleep shorts have a much larger pad for full coverage that also held onto an impressive amount of fluid.
• Tester notes: Testers rave that the sleep shorts keep you "fully protected against leaks" while feeling breathable and lightweight. Some wore them without pajamas but others found they didn't offer enough coverage to be worn solo.
| Absorbency | Moderate to full coverage |
|---|---|
| Sizing | XXS–XXL |
| Care instructions | Machine wash cold with mild detergent, do not bleach, lay flat to dry. |
| Materials | Each of the three styles feature slightly different materials; see product page for details. |
| Return policy | Your first order has a 30-day return period for one worn product. Future underwear products cannot be returned. |
Aerie Real Period Boybrief Underwear
Pros
- Affordable price
- One of the few styles that's dryer safe
- Super soft cotton-blend fabric
Cons
- Limited style availability
Starting at $10, this period underwear from Aerie feels similar to the brand's best-selling traditional underwear. This pick is available in eight style options, including bright shades, neutrals and stripes.
• Lab results: Made with a cotton/polyester blend, they had a soft feel without shrinking after machine washing. It absorbed fluid quickly and showed no run-off when fluid was applied at an angle.
• Tester notes: Especially popular for the soft fabric, one tester said, "They were very comfortable and provided good protection."
| Absorbency | Moderate coverage (2 tampons' fluid) |
|---|---|
| Sizing | XXS–XXL |
| Care instructions | Pre-rinse by hand in cold water. Machine wash on delicate with cold water in a mesh laundry bag and tumble dry low. |
| Body material | 95% Cotton, 5% Elastane |
| Gusset material | Not listed |
| Return policy | Free returns for unworn and unwashed products. |
Thinx Sleep Shorts
Pros
- The perfect shorts to wear if you're staying home with cramps
- Cozy soft materials
- Long, ultra absorbent liner for full coverage
Cons
- Expensive
If you don't like wearing period underwear during the day, you may love this overnight option. They look just like loose shorts from the outside, but this pick from Thinx has super absorbent built-in period underwear for the ultimate loungewear option.
• Lab results: This pick features a larger pad that absorbed fluid quickly and held onto it, showing no leaks during testing. It showed no shrinkage after laundering either — GH analysts also noted that the fabric stayed just as soft after multiple cycles.
• Tester notes: Testers loved that they "offered excellent protection while looking like a typical pair of sleep shorts." Raving that the outer fabric is "super soft," multiple testers noted that the pad is on the bulky side and best for heavy flow days.
| Absorbency | Full coverage (5 tampons' fluid) |
|---|---|
| Sizing | XS–4X |
| Care instructions | Machine wash cold and then hang to dry. |
| Body material | 96% modal, 4% elastane |
| Gusset material | 100% polyester |
| Return policy | Free returns and exchanges within 60 days of purchase. |
Saalt Leakproof Thong
Pros
- Super discreet liner
- Chic, highly rated appearance
- Four color options
Cons
- Very light back-up coverage
Featuring trendy lace detailing and made with silky materials, Saalt's period underwear thongs look and feel just like everyday underwear.
• Lab results: The discreet liner absorbed fluids with ease and held onto them to keep you dry. The liner is smaller than other styles, so it did show some leakage during our evaluations. This pair is best to be worn as backup protection.
• Tester notes: Testers especially loved the thinness of Saalt period underwear and agree that they should be worn alongside other menstrual products. One tester raved that "this thong feels like my favorite lingerie while giving me peace of mind during my period."
| Absorbency | Light coverage (2 light tampons' fluid) |
|---|---|
| Sizing | XS–XXL |
| Care instructions | After use, rinse the thong in cold water to help avoid staining. Then, hand wash or machine wash on cold, preferably in a wash bag made for delicates. |
| Body material | 80% recycled polyester, 20% elastane |
| Gusset material | 92% recycled polyester, 8% Spandex with PUL liner. |
| Return policy | No return portal, but the brand has a Period Bliss Guarantee, promising replacements or refunds if you're not satisfied. |
Aisle Boxer Brief
Pros
- Ultra absorbent core with optional reusable pad
- Uses sustainable materials like Tencel and organic cotton
- Can purchase the reusable pads separately
Cons
- Not all testers liked using a removable pad with period underwear
Aisle period underwear works a bit differently than the other picks on this list. The underwear has a removable insert that absorbs your period (along with an absorbent liner) instead of the protection being solely built-in, so it's kind of like wearing a reusable pad with your underwear.
• Lab results: The pad quickly absorbed fluid and held onto it, showing only minimal runoff leaks on the sides. GH analysts appreciated that this style is available in sizes XXS-5X.
• Tester notes: Not all of our testers liked the concept, but they still found them "comfortable to wear" with a "soft feel." Multiple testers did note leaks.
| Absorbency | Super heavy coverage (8+ tampons' fluid with removable insert; 4 tampons' fluid without) |
|---|---|
| Sizing | XXS-5X |
| Care instructions | Rinse out in cool water, then wash and dry with your regular laundry. |
| Body material | Tencel, organic cotton and spandex |
| Gusset material | ecycled polyester, organic cotton, polyester and TPU laminate. |
| Return policy | First time orders can be returned used within 60 days. Future orders can be returned unused and unwashed within the 60-day return window (these products are then donated). |
How we test period underwear
In the Lab, we evaluated absorbency speed, shrinkage and runoff to ensure that each product we recommend will perform. Then we sent each style home with consumer testers to evaluate comfort and style.
✔️ Absorbency speed: We used cough syrup to mimic the viscosity of menstrual flow just as manufacturers do to test pads and tampons. To measure absorbency speed, we applied cough syrup to the underwear with a syringe and timed how long it took for it all to completely absorb into the pad. Once completely absorbed, we placed filter paper on top then added a ten-pound weight before reevaluating the filter paper to see how well the period underwear held onto the fluid (i.e. to see if the period underwear will keep you dry!). This test was completed when each pair was brand new and again after one and five washes.
✔️ Wash and wearability: Our pros also evaluated shrinkage after one and five washes. After a pair was washed two times, we evaluated runoff, which refers to how much cough syrup will roll off the underwear when it’s tilted to a 45 degree angle. As no one just sits still when on their period, this test determines if the period underwear will be absorbent at different angles too.
✔️ Comfort and fit: In addition to all our Lab evaluations, every pair was sent to five testers of different sizes and menstrual flows to receive feedback on leaks, comfort, fit, absorbency and more.
How to find the best period underwear for you
With more and more period underwear styles available on the market, finding the right pair can be challenging. GH underwear pros found the key features to look for when shopping:
✔️ Absorbency: Period underwear is available in different absorbencies — some styles are meant to be worn without any other period products while others are intended as back-up protection. We recommend having styles with a few different absorbencies to suit different days of your period.
✔️ Styles: Just like regular underwear, period underwear is available in different cuts like high-waisted, bikini, hipster and thongs. Opt for period underwear styles that are similar to the regular underwear you like.
✔️ Use: Period underwear is designed to absorb menstrual flow, so most styles aren't well suited for incontinence (except for a featured style from Knix). Look for styles that suit your needs to have the best period underwear experience. If you're new to period underwear, try an overnight style for nighttime protection — this was a favorite among our testers.
Is period underwear safe?
There have been some concerns recently around perfluoroalkyl and polyfluoroalkyl substances (PFAS) being found in period underwear. PFAS are a group of manmade chemicals that are found in waterproof and nonstick products. There is evidence that exposure to PFAS can lead to negative effects on the immune system and an increased risk of certain cancers. Many brands claim that there are "no measured PFAS" in their products, but this type of testing is relatively recent and companies may not know what to look for as there are thousands of different PFAS chemicals. Therefore, it is unknown whether period underwear has more risk of exposure than any other consumer product that makes skin contact.
"This issue speaks to broader challenges with how toxic chemicals are produced and used in our world today," says Alissa Cordner, Ph.D., co-director of the PFAS Project Lab based at Northeastern University. "It is quite possible that a product manufacturer would be unaware of PFAS in some of their component materials because the global supply chain lacks transparency when it comes to chemicals. But this is still a problem, and product manufacturers have a responsibility to ensure that their products are safe for consumers and for the environment."
Period underwear, specifically, faces another hurdle: There has been long-term bias in scientific testing around products aimed at women and people of color. "So this may be part of why we don’t know a lot about exposure to toxics through period products," says Cordner.
How to clean period underwear
To make sure you have the best experience with period underwear and that each pair lasts long term, make sure to follow the brand's care instructions closely.
Generally, you should rinse out your period underwear in the sink or shower before laundering to avoid any stains on your other clothing items. Using a mesh garment bag when laundering helps delicate items last longer. Many testers said they preferred to hand-wash their period underwear with a mild detergent. Read our guide to the most effective way to hand-wash your clothes.
Why trust Good Housekeeping?
Emma Seymour is a Senior Textiles Product Analyst at the Good Housekeeping Institute. She’s been at GH for more than four years, testing all of the above period underwear and coordinating consumer testers. She has also led tests for other intimate categories, including bralettes and wireless bras. With a degree in fiber science and apparel design from Cornell University, she has extensive research experience, particularly focused on athletic wear.
To research the safety of period underwear, Emma spoke with Alissa Cordner, Ph.D., the co-director of the PFAS Project Lab based at Northeastern University. She is also an is Associate Professor of Sociology and Paul Garrett Fellow at Whitman College. She teaches courses in sociology and environmental studies, including Environmental Sociology, Environmental Health, Social Research Methods, Sociology of Health and Illness and Environmental Justice.
Emma Seymour (she/her) is a senior product analyst at the Good Housekeeping Institute's Textiles, Paper and Apparel Lab, where she has led testing for luggage, pillows, towels, tampons and more since 2018. She graduated from Cornell University with a bachelor of science in fiber science and apparel design and a minor in gerontology, completing research in the Body Scanner Lab on optimizing activewear for athletic performance.
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