I didn't think underwear could change my life. Then I started bleeding into pairs of underwear meant to soak up menstrual blood without leaking.
There used to be a term that those who menstruated were familiar with: period panties. These were pairs of undies that lost their beauty after many battles against blood, developed permanent stains, and were then only worn during that time of the month. The modern invention sold as “period underwear,” on the other hand, is quite different. It’s a technology-laden class of undergarment that absorbs liquid without leaking or staining, leaving you feeling comfy, dry, and secure. Sometimes, period underwear can even be pretty.
Before I got up the nerve to try period underwear, I was unsure how they became so popular. Mostly this was because I didn’t quite get how they worked. Don’t you just leak through the edges? Doesn’t it feel like you’re sitting in a diaper? Do you have to change them multiple times a day? The answer to all those questions is no—if you’re wearing the right absorbency level for your flow. And if you aren't currently menstruating, they could still provide protection against incontinence and discharge. Basically, it's a marvelous upgrade to a necessary garment.
Code Red
I got my period for the first time when I was young and for many years it was horrendous, for lack of a better word. It was heavy and painful, with cramps that left me unable to move for hours. Menstruation during those first few years tends to be abnormal and sporadic anyway. It often doesn’t follow a schedule, so you can’t easily keep track of what days you need to be prepared with a stockpile of pads and tampons.
A period could start at any moment, as it sometimes did while I was sitting in school. This resulted in many embarrassing days where I went to the bathroom and found blood stains in my pants, or worse, was told by a fellow classmate that they could see blood. I had to walk down to the nurse’s office and wait for a parent—sometimes my dad—to drop off new pants. When you’re a kid, the thought of anyone seeing even a pad in your purse was paralyzing, never mind a class full of elementary schoolers seeing your bloody behind. (Now I'm writing about my period for WIRED, go figure.)
Not long after my first period, there was a school field trip I remember vividly. When I went to the bathroom, I realized that I had started a new cycle. I had to ask my teacher for a pad. She handed me one that was super absorbent, thankfully, but it was also thick and uncomfortable. It felt like I had just put on a pull-up diaper. I was convinced everyone could hear the plastic within the pad crackling as it rubbed together in my pants. I can’t help but think how much different those years would have been if I had period underwear all along.
As I’ve become an adult, I’ve realized that menstruation is normal, of course, and not embarrassing like I once thought it was. Nobody wants to have blood stains in public, but I’ve lost the shame associated with periods and can now talk openly about them with my boyfriend and, really, anyone else who will listen. But still, periods can be painful, annoying, and unpredictable. They can be expensive too; in most states, tampons, pads, and menstrual cups are taxed as luxury items, not necessary medical supplies. Disposable menstrual products are also wasteful—pads and tampons are made to be thrown away, after all. According to an article from the fashion and lifestyle publication Image, a pad is made up of around 90 percent plastic, and one single tampon takes longer to degrade than most women are alive.
How It Works
I recently wrote a buying guide offering advice about different types of menstrual products that can help reduce environmental waste. There are comfortable menstrual cups and reusable pads, or even subscription services if you’re not ready to give up tampons entirely, but period underwear stood out in my testing for its simplicity and effectiveness. Instead of going through multiple pads or tampons per day, you can put on a pair of underwear, just as you do every morning, and change pairs before bed. Of course, how long you can wear them before needing to change into a new pair will depend on the type of underwear you buy, as well as your own flow.
Most brands use about three layers of absorbent material in the crotch of the underwear—some go all the way up the back too—that traps liquid and keeps it from transferring to your clothes. Similar to a pad keeping liquid in, the liquid-locking materials in the underwear keep blood from leaking out the sides onto your legs. I started to notice some blood reaching the seams of the underwear when I chose the wrong absorbency level, but it took a lot of blood to get to that point.
Even the thickest and most absorbent pairs I tried, which are designed like shorts, didn’t feel like a diaper. They felt kind of like a supportive pair of yoga shorts, which means there’s even more protection against blood leaking through the edges. To be clear, these thick, 24-hour protectant pairs feel a bit bulky under tight clothes, so I plan accordingly and opt for pants that are looser on those days. But I’d take thick shorts and peace of mind over a bulky pad anytime.
I’ve tried six different brands with differing absorbency levels. You can read about them more in-depth in the menstrual products guide, but I have some favorites. If you want to make the switch, I suggest trying a few different pairs to find what works best for you and your body.
My favorite is Modibodi. It has the biggest range of absorbency levels with heavy-overnight and 24-hour options that should last you all night or all day without worry. It also has a patent on its lining design. The lining includes a top bamboo layer that wicks moisture and curbs odors, plus a merino wool middle layer that absorbs that liquid and keeps it locked in place to avoid getting your clothing bloody (or your skin from feeling wet). There’s also an extra waterproof bottom layer as an additional defense against blood soaking through them and staining your pants.
Another of my favorite pairs comes from the brand Knix. The company's nylon styles were by far the comfiest; the silky feeling against my skin was a nice change of pace on those normally uncomfortable days. If you’ve ever felt like you could take on the world because your bra and underwear match despite no one else knowing, you’ll understand the feeling these nylon underwear give me. Maybe I’m bleeding and pretending my insides aren’t cramping up, but at least my underwear feels good, you know?
Knix uses a cotton top layer with spandex and carbon for moisture wicking and odor suppression, plus polyester middle and exterior layers for absorbing and trapping liquids.
Safety Concerns
I couldn’t rave on about how much period underwear has changed my life without mentioning the elephant in the room: in 2020, PFAs were found in certain pairs of Thinx menstrual underwear. Sierra Club writer Jessian Choy sent in several pairs of her Thinx underwear and Lunapads (now called Aisle) to Graham Peaslee, a physics and chemistry researcher at the University of Notre Dame. Peaslee found high levels of per- and polyfluoroalkyl substances (chemicals commonly known as PFAs) in two of the three Thinx pairs, but not in the Lunapads. (Peaslee had previously discovered PFAs in fast-food wrappers.)
“It was enough PFAs that we are sure it was intentionally added to make a layer water resistant—which is a lot of PFAs in general,” Peaslee told WIRED when asked about his findings. Peaslee can't say whether the amount of PFAs found in the underwear posed a risk to the wearer (PFAs are more harmful if ingested than if worn) but he does believe such “non-essential” use of these toxic chemicals should be avoided.
I talked to every company I tried, including Thinx, and all assured me that there are no toxic chemicals in its underwear. Some even started including language in their marketing noting that their products are PFA-free. We’re going to continue researching the topic, but we think these brands are being truthful about the makeup of their menstrual underwear, especially after this finding.
There’s not a lot of research in general about menstrual products. In fact, when I reached out to the American College of Obstetricians and Gynecologists when I first wrote the menstrual products guide, it couldn’t answer much about any menstrual products at all because of the lack of peer-reviewed scientific research. Like a lot of aspects of personal care that women deal with, we have to take a leap of faith that the products designed for us aren’t going to harm us.
I just know that there’s little that makes me feel good when I’m bleeding from my vagina for the fifth straight day, and if period underwear can help me even a little, I’m not letting it go.