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10 best period underwear of 2021: Thinx, Knix, ModiBodi

Pads and tampons aren’t the only period care products out there. Gynecologists explain what makes period underwear different — and whether a pair is actually worth it.
Illustration of a Woman wearing the ModiBodi Sensual Hi-Waist Bikini, a Leakproof Thong,  Saalt Elemental Mesh Hipster, Aisle Boxer Brief and Rael Reusable Period Underwear
Unlike pads and tampons, period underwear is designed to be worn over and over again. ModiBodi ; Saalt ; Aisle ; Rael

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Traditionally, pads and tampons pack the shelves of period care aisles — the modern versions of both have been around since about the 1920s. Since then, period care products have dramatically changed. When it comes to marketing, you’re likely to see realistic red fluid used in commercials instead of blue dye. When it comes to technology, the Food and Drug Administration approved the first birth control pill that can stop periods indefinitely back in 2007. This year, period care products officially became FSA- and HSA-eligible, as well.

What’s actually popular for that time of the month has also shifted — recently, there’s been a rise in alternative period products, including menstrual cups and period underwear, which is specifically designed to be able to handle the different flows of that time of the month. Google searches over the past year for period underwear are even higher than those for period pads or menstrual cups (tampons still take the top spot, though). There are two kinds of period underwear out there, as Racked previously pointed out: ones that keep pads in place and others that act as menstrual management that can even take the place of tampons and pads.

SKIP AHEAD Best period underwear of 2021

“Period underwear is really just what it sounds like: They're specially designed undergarments that you wear when you're menstruating to take the place of, or use in tandem with, tampons and pads,” explained board-certified gynecologist Tamika K. Cross, MD. Unlike other period care, period underwear doesn’t have to be changed as frequently, either — the FDA recommends changing a tampon every four to eight hours and the American College of Obstetricians and Gynecologists advises the same for pads, plus suggests reinserting a menstrual cup twice a day after emptying and washing it out. Brands like Thinx and Ruby Love don’t clock how long their underwear lasts — just how absorbent a pair can be. “You don’t have to change them as often and you don’t have to worry about misaligning them in your real underwear, which can cause a leak as your body is naturally shifting throughout the day or night,” Cross mentioned.

To understand how exactly period underwear works, along with its advantages and limitations, we talked to three gynecologists and gathered options to consider as well.

How period underwear works

Period underwear is actually very much like underwear, coming in all sorts of styles — take this brief from period care company Aisle or these trunks from gender-fluid fashion label TomboyX. You’ll see them offered in boyshorts, bikinis, briefs and thongs, Cross mentioned.

The key difference, however, is that while period underwear might look like a standard pair you’d find in a pack, it “has a built-in pad that pulls moisture away from the surface,” said Jennie Hauschka, MD, an OB/GYN based in Charlotte, North Carolina. Usually, you can’t even tell there’s a pad as there’s “no bulging, adhesive, wings, or any of the other annoying issues that come with traditional pads,” she added. Generally, period underwear falls into two categories— those that “can be used primarily as menstrual protection, as a pad would be worn” and the others that act as backups to menstrual cups and tampons, according to Hauschka.

Much of the period underwear you’ll find tends to be made mostly from cotton, with some nylon or elastane thrown in for stretch and durability, Hauschka said.

The underwear works to absorb blood, and there are three types of absorption levels you’ll usually find that experts agree on —for light, moderate or heavy flows. That’s “similar to the different types of tampons, pads and pantyliners on the market,” Hauschka explained. “For example, ‘heavy day’ or ‘overnight’ menstrual underwear can hold as much as 5 tampons’ worth of blood, which is more than most pads or menstrual cups can hold, but the light absorbency style holds about as much as a pantyliner. So you choose your period underwear for the day based on how much bleeding you have.”

“Just like with pads or tampons, you pick based on how heavy or light your flow is. So for a much heavier flow, you would pick a more absorbent one versus somebody who doesn't have a heavy flow, they may be able to pick something lighter,” Cross added. That’s the same sentiment that Hauschka shared: Choose one based on how much you tend to bleed on your period. Both Cross and Hauschka recommended trying out different absorbances to get comfortable with wearing them and to see how one over another feels with your body.

Best period underwear of 2021

To find highly rated period underwear, we separated the following pairs into three categories — light, moderate and high coverage — based on the expert guidance we received above. As one gynecologist noted, some of the most absorbent period underwear on the market can hold as much liquid as five regular tampons (there are brands like Thinx that even offer slightly more than that) — so we considered light absorbency to be similar to one to two tampons, medium ranging from three to four and high holding as much as five (or more). This is also the way in which many brands define their different offerings.

Light absorbency period underwear

1. Thinx Cheeky

Thinx is one of more well-known period underwear brands. And the company also has a line for tweens and teens called Thinx (BTWN) and another designed for bladder leaks called Speax. It offers only two styles in its lightest absorbency category: Thong and Cheeky, both of which can hold up to one tampon’s worth of blood. The underwear is certified by OEKO-TEX, meaning it’s been tested for harmful substances. It features a seamless fit and is made from nylon and elastane. It currently comes in sizes XXS to 4X and four colors, Dusk, Black, Fig and Beige. This cheeky pair boasts an average 4.8-star rating over more than 950 reviews at Thinx.

2. ModiBodi Sensual Hi-Waist Bikini

ModiBodi makes underwear for women, men and teens. Its period underwear is among its most popular pairs — this pair has earned an average 4.9-star rating over more than 2,800 reviews. You’ll also find a range of styles on the site including a French Cut and another called Boyleg, which offers a lower rise. The Sensual Hi-Waist Bikini is meant for lighter flows, or about the same as two tampons. It’s designed with a higher leg and sits right at the hip. The bikini also is made with a stain- and bacteria-fighting lining, the company claims. There are two colors, Beige and Black, and 10 sizes, XS to 6XL, to choose from.

3. Proof Leakproof Thong

Notably, period label Proof designs underwear for different leaks, including these three options: postpartum, workout and maternity. This thong is supposed to help with light leaks and erasing panty lines, and it has the absorbency of one tampon. The pair is made from what the brand describes as a breathable microfiber and features a lower rise silhouette. You can use this period underwear with a tampon — it’s meant for spotting, sweat and other discharge. It’s available in two shades, Black and Sand, and sizes XS to 3XL.

Moderate absorbency period underwear

4. Rael Reusable Period Underwear

Along with period underwear, Rael carries its own collection of menstrual cups, pads, tampons and panty liners. Absorbing as much as three tampons, this pair is meant to look like the everyday underwear you might be used to wearing. The underwear is made with four layers — including one from cotton and another that’s meant to protect against moisture and odors. In terms of fit, the company says this pair is stretchy while still hugging your curves. It currently comes in four sizes, Small to X-Large, and you can choose to bundle the underwear in a pack of one, two or three. This underwear has earned an average 4.2-star rating over more than 250 reviews at Rael.

5. Saalt Elemental Mesh Hipster

Saalt is probably better known for its popular menstrual cups. But the brand also offers its own kind of period underwear called Saalt Wear, including bikinis and briefs. The Saalt Elemental Mesh Hipster is its most top-rated pair, boasting an average 4.5-star rating over more than 100 reviews. The pair is designed to absorb what two to three regular tampons can and acts as extra coverage for a tampon or cup, according to the company. The underwear is made from sheer mesh and offers a stretchy waistband with a mid-rise. This pair currently comes in five colors, including Desert Sand and Quartz Blush. You can choose between sizes XS to XXL.

6. Aisle Boxer Brief

Aisle, which was originally named Lunapads, also has its own line of liners, pads and cups. This boxer brief is designed with a statement waistband that says the brand’s name. For more coverage, the brand claims this brief can hold as much as four tampons — but it also comes with a booster that you can tuck into the ends of the gusset for even more protection (or the same as two tampons). The pair is meant to be completely worn on its own — no pads or tampons necessary. The underwear is offered in sizes XXS to 5X and three colors: Black, Goldenrod and Green.

7. Cora Period Underwear

Eco-friendly tampon and pad company Cora says it uses organic cotton in many of its offerings. Its period underwear is supposed to absorb the same as three regular tampons — but you can also opt to use it with your other period care products. The pair is designed to be flexible, especially for those with active lifestyles, according to the brand. It features a moisture-wicking core. It’s available in sizes XS to XXL and packs of one, three of five.

High absorbency period underwear

8. Knix Super Leakproof High Rise

Knix’s period underwear falls into two categories — light-medium and heavy-super coverage. The brand’s most absorbent underwear is equivalent to eight tampons and this pair is among its most top-rated: It boasts an average 4.6-star rating over more than 850 reviews. The pair features an extended gusset that’s 9 inches long and 4-way stretch that’s meant to relax with washes for a more comfortable fit, the company claims. In terms of fit, this period underwear sits at the natural waist. You can choose between sizes XS to XXXXL and 14 colors that are currently in stock.

9. The Period Company The High Waisted

As its name implies, The Period Company is centered around period underwear — the brand also offers a reusable pad that’s a more recent addition. Along with The High Waisted, you’ll also find The Bikini with a lower rise and The Adaptive Bikini, which features velcro closures. This pair can hold up to 10 tampons’ worth of blood. It’s made with organic cotton and spandex, according to The Period Company. You can choose between six colors, including Mahogany and Forest, and sizes XS to 6X.

10. Thinx Super Hiphugger

Holding the same as five tampons, this pair is among the most highly rated that Thinx carries — it’s also the brand’s original bestselling style that’s been updated to be more absorbent than its classic collection. The pair has earned an average 4.8-star rating over more than 2,000 reviews at Thinx. Made from nylon and elastane, the Super Hiphugger features a zigzag pattern at the waist. It’s available in three colors — Black, Fig and Dusk — and sizes XXS to 4X.

What makes period underwear different from other period care products

To understand the common period care products you’ll come across, here’s the difference between pads, tampons and menstrual cups as described by Cross — which will help in knowing what period underwear can do.

  • Pads are disposable napkins that are placed on your underwear
  • Tampons are an “absorbent piece of cotton” inserted inside you that amass blood
  • Menstrual cups are small silicone cups that also collects blood (and are reusable)

Period underwear stands out from tampons, pads and menstrual cups because of its absorbency, according to all the experts we talked to. Hauschka even went as far to say that it’s “the most absorbent period protection available.” “Period underwear can usually absorb more blood than the average pad or tampon because they can be worn for longer periods of time,” explained Heather Irobunda, MD, an obstetrician-gynecologist based in New York City.

Many of the period underwear out there will be marketed as period- or leak-proof — such as this high-rise panty from intimates label Knix — and while the undergarments can provide protection against leaks, leaks can sometimes happen. But it’s more likely that period underwear will catch blood “before it reaches your clothing or bed sheets or other items you don't want accidently stained,” Cross said. And another benefit of using period underwear instead of pads? With a pad, there’s a worry about “misaligning them in your real underwear, which can cause a leak as your body is naturally shifting throughout the day or night,” she noted.

Unlike pads or tampons, which are one-and-done after every use, period underwear is also reusable. “The difference is that period underwear can be washed and reused — similar to menstrual cups. Menstrual cups and period underwear are similar because they are both designed to be reused and they both can be worn for longer periods of time than disposable period products,” Irobunda explained. Both Irobunda and Hauschka recommended changing period underwear once every 12 to 24 hours. The reusability of period underwear contrasts with the waste that can build in landfills from tampons and pads. But you can also find disposable period underwear, too — like this pack from Rael’s.

Is period underwear worth it?

All three experts we spoke to agreed that period underwear can be a useful option, especially because of its absorbency. Irobunda argued that it’s probably more practical for those who prefer pads over tampons. That absorbency also depends on the style you choose and what size pad or tampon you’re comparing it to or that you’re used to wearing, Cross told us. But for those with heavier flows, it might be better as a backup for pads or tampons, both Cross and Hauschka said.

And it’s not that period underwear is better than other menstrual care — this is more a matter of personal preference above all, Cross mentioned. Hauschka’s advice? “Look at each brand online and see what options they offer. If you’re using it as back-up, you may not need the highest absorbency. If you are using only the underwear as period protection, you may need the super absorbent for night time or your heaviest period days. It is helpful to try different absorbency options and different brands to see what is best for you.”

As far as the downsides of period underwear, it’s not waterproof like tampons are when it comes to swimming or being around water so it won’t offer protection there, Cross said. Instead, a pair might absorb a lot of water, leading to an “undesirable situation,” she added. Plus, she mentioned the lack of portability of period underwear — you can’t carry it around as you would an extra tampon or pad in a pocket.

Period underwear can be helpful at any age, so someone can “be out doing activities for longer between bathroom breaks,” Hauschka said. Still, it can be especially convenient for teens as “they’re learning what works for their bodies and finding the best ways to use and manage personal hygiene products,” Cross explained. It’s a similar feeling that Hauschka shares, explaining that adolescents “may find it more comfortable than having to stick a pad in their underwear.” As pads can shift, they’re “more likely to result in ‘accidents’ than menstrual underwear,” Hauschka added. She also recommended them for athletes in particular for “a comfortable and dependable way to manage their period.”

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