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Love pads and pantyliners, but hate the waste they create? Enter period underwear. In recent years dozens of brands have popped up with reusable period underwear that can absorb menstrual fluid to keep you comfortable and dry. Most can hold up to a tampon's worth of blood or more, and can be used as a complete replacement for other menstrual products or as a backup to catch leaks.

Thinx and Dear Kates were some of the first major brands on the scene (though others have been around longer), but now there are many options to choose from at different prices. To narrow down the selection, I've tested and used several different brands to find the best. 

My main criteria were comfort and absorbency, but I also judged how bulky each pair was. Unless you're wearing them only overnight, you'll want a pair of period underwear that doesn't look or feel like a diaper. I wore them under tight-fitting work pants to check for panty lines, bunching and any other signs I was wearing period underwear.

What are period underwear?

Period underwear use layers of absorbent material to collect menstrual blood. For those who do not use tampons or menstrual cups, these underwear can replace pads and pantyliners. They can also serve as backup protection against leaks from a tampon or cup. 

Like regular underwear, they come in plenty of different styles ranging from thongs to briefs. Most companies also offer levels of absorbency from light to heavy.

Why should I use period underwear?

The main benefit of period underwear is that it cuts down on waste. The average period lasts three to five days and in that time, some can easily go through four tampons or pads per day -- even more if you have a heavy flow and long period. All of those disposable pads and tampons add up over time, costing money and creating waste.

Another benefit of period underwear is that they are typically softer and more comfortable against your skin than disposable pads. And when you're on your period, being comfortable is really all that matters.

What are the downsides of period underwear?

Period underwear won't work for everyone. Because of the extra layers of fabric, some period underwear can look bulky under your clothes, especially if they are tight fitting. There's also a risk of leaks and stains because the underwear press up against whatever bottoms you're wearing and can transfer to them (the same is true with pads). And, despite their best efforts, most period underwear will feel a bit damp or wet as it collects fluid, which can feel uncomfortable.

Without further ado, here are the best period underwear you can buy.

James Martin/CNET

ModiBodi's underwear have a lot of things going for them. First, all of the styles are made from natural and/or recycled fabrics, such as bamboo, merino wool and recycled nylon. They are also designed for both periods and incontinence, so they work for a lot of different needs.

The light to medium absorbency "boyleg" style I tried were incredibly comfortable to the point where I didn't want to take them off. I thought that the wool gusset would be uncomfortable (because wool can be scratchy), but it's actually really soft. Wool is a smart choice here because it wicks away moisture and keeps you feeling dry. That's why a lot of socks and base layers are made from it.

Another reason I liked ModiBodi is the impressive size range that accommodates waist sizes from 22 to 48 inches -- and that's just the adult women's sizes. There's also a teen line of products for smaller bodies.

Modibodi makes more than just period underwear -- they have men's absorbent underwear to catch bladder leaks and sweat, breastfeeding bras and tops that absorb milk, period swimwear and sleepwear, postpartum underwear and even cloth diapers for babies. The company also recently launched adaptive underwear, designed for anyone with mobility limitations

Advertised absorbency: Light to moderate coverage styles -- two regular tampons (10ml), Moderate-heavy coverage styles -- two to three regular tampons (15ml)

Test results: I tested each pair of underwear on this list to see exactly how much liquid they can hold versus what the company claims. The full details of my methodology are below. 

Modibodi absorbed water the slowest of the underwear I tested, however it felt the most dry to the touch once it fully absorbed compared to the rest. If you have a light to medium period, you'll likely feel dry wearing these underwear.

Size range: XXXS to 6XL

Price range: Specifically for the underwear, $18 to $35

James Martin/CNET

Out of all the underwear I tested for this story, the Dear Kate Nellie Hipster Mini felt the most like regular underwear. That's a good thing, because no one wants to walk around feeling like they're wearing a diaper on their period. They are made from a silky nylon, true to size and aren't bulky at all.

Dear Kates sells thongs, briefs and hipsters, with some styles available in two different options -- mini and regular. The regular style has more coverage than the mini and is better suited for a heavier flow or for wearing for longer stretches of time. The mini style is good for lighter days or when you just don't need as much coverage.

I liked Modbodi and Dear Kates equally, so choosing between the two was tough. Dear Kates are a bit more slim, so if you need period underwear to wear under your normal wardrobe that has excellent leak protection, get these. If you need more variety of absorbencies (or want to save a few dollars), try ModiBodi.

Advertised absorbency: 1.5 regular tampons (~10ml)

Test results: All period underwear promises no leaks, but the Dear Kates lived up to the claim. It absorbed water very quickly without pooling and didn't leak past the absorbent fabric into other parts of the underwear. Even when the gusset was fully saturated, the outside of the underwear stayed bone dry. If leaks are a concern for you, these are the period underwear worth getting.

Size range: XS to 3X

Price range: $34 to $46

James Martin/CNET

Thinx underwear are available in five different absorbency levels from lightest (replaces up to one tampon) to super (holds up to five tampon's worth of fluid). There are several style options to suit anyone's taste, from full-coverage briefs to thongs. Their original styles are made with nylon and a cotton gusset (the extra strip of fabric in the crotch that absorbs liquid), but the company also has an organic cotton line.

Beyond just underwear, Thinx also sells sleep shorts, leotards and workout bottoms that absorb fluid, so you're covered for any activity.

I've owned a pair of Thinx for several years and I've been impressed with the quality and performance of them. My original pair are the Sport style, which I still own and use, and I also got to try the Hiphuggers. Both of those pairs are nylon on the outside so they feel silky and smooth, and the inside is lined with cotton.

Out of all the pairs I tested, Thinx has the most stylish underwear, with little details that make them feel sexy, such as lace waistbands and mesh panels.

Advertised absorbency: Hiphugger style holds up to three regular tampons (15ml), though Thinx advertises 27ml as the max.

Test results: In the water test, the Thinx performed well, but I did encounter some leaks that seeped into the less absorbent parts of the underwear. That said, in real-world testing, I haven't experienced any leakage, though I did notice the underwear takes awhile to wick away moisture.

Size range: XXS to 4X

Price range: $24 to $42

James Martin/CNET

In keeping with the trends, American Eagle's underwear brand Aerie now sells period underwear, though your choices of styles and colors are limited.

If you need period underwear for sleeping, these are your best bet because they have a huge gusset that extends far back to catch any fluids. 

If you're already familiar with Aerie's boybrief style, these have the same fit, but they are bulkier than the other underwear I tested. They were remarkably comfortable and fit well, but because they're a bit bulky you'll want to wear these under thicker pants like jeans, or save them for sleeping.

Advertised absorbency: Two regular tampons (10ml)

Test results: These underwear passed the water test with flying colors. They absorbed water quickly with no leaks and didn't feel soaking wet after. Everything I want in period underwear.

Size range: XXS to XXL

James Martin/CNET

Aisle underwear set themselves apart from the rest with a removable insert that makes them even more absorbent.

While the insert was a bit tough to get into the gusset and have it lay flat, the underwear felt way less bulky on my body than I expected them to. With the insert, you're going to have some bunching in the crotch, but the extra absorbency makes it worth it, especially for wearing at night.

Without the insert they still hold about two tampons worth of fluid. The pair I tested have a sport design and were soft thanks to the organic cotton and Tencel -- a fabric made from wood that wicks away moisture. These came in second for the award of underwear I didn't want to take off. 

Advertised absorbency: Bikini style holds two regular tampons (10ml), four tampons with optional absorbency booster (20ml)

Test results: Aisle's underwear performed well during the water test -- they absorbed all of the fluid quickly without leaks. However, they took a while to dry and were still wet to the touch after 30 minutes.

Size range: XS to 5XL

Price range: $32 to $46

James Martin/CNET

Bambody's absorbent underwear are designed for both periods and post-partum. The full-coverage briefs I tried are made from bamboo, which made them so soft. I highly recommend these for lounging when you just want to be comfortable, which is not always easy during your period.

These underwear also impressed me on price, with some styles coming in at nearly half the cost of other period underwear I tested without any sacrifice in quality or absorbency.

As a heads up, these ran small for me, so size up when ordering. Bambody says on its packaging that if you expect to have a heavy flow, you'll want to use additional "sanitary wear" aka pads, tampons or a menstrual cup. However, you might not need them.

Advertised absorbency: Two regular tampons (10ml)

Test results: Despite the label warning me to use additional protection for a heavy flow, the Bambody briefs were a standout in the water test. They did a great job of absorbing the water right where I poured it, rather than flooding the entire gusset. That means you'll likely feel much more dry wearing these than the others on this list, especially if you have a heavy flow.

Size range: XXS to 6XL

Price range: $14 to $39

James Martin/CNET

I appreciate that Proof's underwear is sleek and has flat seams so they don't look conspicuous under your clothes, but the leak protection was lacking.

The Leakproof Full Coverage Hipster style I tested felt comfortable to wear -- they are lined with cotton and use nylon on the outside. However, the underwear couldn't hold the full amount of liquid it advertises without leaking out the front, sides and back. 

Given how many other options on this list absorbed fluid well with few (if any) leaks, I can't recommend Proof over those.

Advertised absorbency: The Leakproof Full Coverage Hipster holds up to five regular tampons (25ml).

Test results: Unfortunately, Proof didn't fare well in testing -- the underwear leaked at the front and back of the gusset. The water that didn't leak absorbed quickly, but the gusset stayed wet to the touch long after the test. If you have a heavy flow, you likely won't be comfortable wearing these for several hours.

Size range: XS to 3XL

Price range: $25 to $43

Not yet tested

Knix

I've yet to have the chance to try out Knix, but the list wouldn't be complete without them. Like Thinx, most Knix underwear is made from nylon that gives them a slick, smooth feel. Knix also has pairs made from cotton and modal. On all styles, the gusset is made with Fresh Fix Technology, a layer of absorbent polyester and fabric infused with carbon to help minimize odors.

Advertised absorbency: Up to 8 teaspoons of liquid (39ml)

Size range: XS to XXXXL

Price range: $23 to $38

How I tested

I'm no stranger to period underwear and other "alternative" period products (Where my menstrual cup fans at?), so I jumped at the chance to write this guide. When you're on your period, staying dry and comfortable are the top priorities, so I judged every pair of these underwear through that lens.

I first tested all of the above underwear for fit, to determine if they are true to size. That mostly involved a lot of trying them on, wearing them under pants to see how bulky or slim they were and if you could see panty lines.

Next, I tested the absorbency to see if it lived up to the claims. Since it would take me well over a year to test each one of them while on my period, I developed an easily repeatable method in my home lab (also called the kitchen).

I washed each pair of underwear according to the label and air dried. You'll want to wash your period underwear before you wear them for the first time to remove any starch or other chemicals used in the manufacturing process. Air drying is important to preserving the underwear's absorbency -- fabric softener or dryer sheets can leave a film behind that doesn't allow moisture to pass through.

Next, for each pair, I checked how many tampons' worth of fluid they can hold and converted that amount into millimeters. This is not exact because there's some variation in tampons across brands, but in general, one regular tampon can hold 5ml of liquid.

I slowly poured that amount of water over the gusset of the underwear to see how quickly it absorbed and if any water leaked. I left them for 30 minutes and then checked to see how dry they were after absorbing the water. Some were just as wet as when I started the test, others were dry enough to comfortably keep wearing. 

I will caveat that this is not a perfect test. Menstrual fluid usually leaves your body slowly over the course of a few hours, though some people experience short gushes throughout the day. Some of the underwear I tested didn't absorb the entire amount of water right away and/or leaked, but that doesn't mean they wouldn't work for your period. If your flow is steady over the course of a day, period underwear will have time to absorb it slowly, which will minimize leaks.

If you pass multiple clots during your period or experience repeated gushing/flooding, period underwear might struggle to absorb fluid and keep you feeling dry. 

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The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.