About Proof®

Proof® undies look and feel just like normal undies but have built-in, leakproof technology.

Our patented Leak-Loc® technology has multiple layers that draw in moisture and help lock in leaks. The Quick-Wick liner helps pull moisture away from the body and into the super absorbent core.

Our undies are designed to help you to feel fresh and dry. Plus, our styles are machine washable and reusable, and can be worn as normal undies.

To learn more about how Proof® works, keep reading.

Proof undies combine patented technology with soft, comfy fabric and thoughtfully designed details. Please see individual product pages for material contents.

Proof® undies are designed for all day comfort. Our undies feel just like your favorite pair of regular underwear but with built-in protection.

Founded by three sisters in 2020, Proof® was built with a mission to provide women with meticulously designed, expertly constructed period underwear. They decided it was time for a different kind of period experience—one where women can feel their most confident duringthat time of the month”. Fast forward to present day, Proof® and the forces at Always decided to come together to bring you even better protection with higher absorbency and technology. Proof® powered by Always is the period solution that has your back...period. With absorbent period underwear—our heaviest style can hold up to 9 regular tampons’ worth of flow—Proof® powered by Always will completely revamp your top drawer.

Our period underwear features patented Leak-Loc® technology that has multiple layers that draw in moisture and help lock in leaks. Our period underwear are buttery soft and made to move with your body. With no-show smooth bonded edges that are seamless under clothes, you can look and feel your best, regardless of whether you’re experiencing a light or super heavy flow. Take on the day or a restful night’s sleep worry-free wearing our period underwear.

Ever heard the saying, there’s something for everyone? At Proof<sup>®</sup>, we design our products for everyone - teens included. Available in a variety of styles and sizes, we do everything we can to deliver just the right fit. While we know how important protection is, comfort and fit is just as important. When you find period underwear that checks off all the boxes (like ours) you will have found the new staple in your underwear drawer.

Our period underwear is designed to deliver unseen but powerful protection. Once you make the switch to Proof <sup>®</sup>, you’ll never look back. From delivering up to 100% leakproof protection to a personalized customer shopping experience, we are committed to taking care of our customers and delivering the best products possible. Leaks are not something we take lightly. Our leakproof period underwear is offered in a variety of absorbency levels, so you can feel confident from your lightest day to your heaviest. You can choose from a variety of absorbency levels, styles, and cuts. We redefine the way you think about period protection...period. Try our washable and reusable period underwear for yourself! 

How It Works

Period flows change, we get it. As part of our motive to keep you feeling your best no matter what kind of flow you’re experiencing, we offer a variety of absorbency levels for all the days. On your light days, you may want a lighter absorbency panty or thong, while on heavier days, you may opt for something with a higher absorbency level, and for overnight you might want something with some added coverage. We encourage you to stock up on a variety of styles so that you’re prepared for any flow, any time.  

However, there are no rules that say when you can or can’t wear a particular pair. Whatever makes you the most comfortable, wear it. As you browse through our assortment, look for the blood drop icons that serve as an indicator of absorbency level. 


Washable underwear for periods by Proof® is available for heavy and super heavy periods. Our heavy and super heavy absorbency levels offer enhanced leak protection. The Proof® by Always Super Heavy Brief holds up to 7 regular tampons, and the Proof® by Always Overnight High-Rise Brief holds up to 9 regular tampons and has front-to-back coverage.

Our reusable period underwear is about to be your new BFF thanks to its buttery soft material and absorbent technology made for your unique flow. 

Our reusable underwear for periods is a product that is made with women’s comfort and wearability in mind. With fabric that moves with you and super absorbent layers in the gusset, our reusable period underwear is an essential product for that time of the month, or anytime at all! Our reusable period underwear will help you throughout your period week. You might be thinking, “sounds great, but what do they look like?”. Don’t worry, we’ve got you. From our signature Lace Cheeky to full coverage Briefs and our Leakproof Thong, we know that you don’t stop wearing your favorite pair of underwear just because your period is in full force. 

Our patented Leak-Loc® technology is absorbent enough for the heaviest of flows, but slim and flexible enough for whatever your day or night looks like. Say hello to our leakproof, absorbent layers, which include our Quick Wick lining that pulls moisture away from your body, and a buttery-soft waterproof fabric crafted with bonded, Leak-Loc® edges to hold it all in. This game-changing combo is thoughtfully designed to help keep you feeling dry.

Period underwear is crafted with different absorbency levels to match your flow. Shop by absorbency levels to determine which pair or pairs should be in your own collection.

If we rambled about all of the benefits of reusable period undies, we’d be here all day, but here are some of our top reasons to try Proof® by Always period underwear—you'll never look back:  

  • From the moment you put them on, you’ll feel more confident. 
  • They’re available in many styles. It’s easy to assume that something as functional as reusable period undies can’t be stylish, right? Wrong. Proof® is all about form and function. 
  • They’re liberating! A worry-free period? Yes, please. 

Underwear that absorbs your period doesn’t have to be ugly. With an abundance of styles and absorbency levels, there are perfect undies for everyone! On our website, you can shop for undies by leak type, absorbency level, style or cut, and more.  

From lace options to full coverage sleep briefs, the style choices are seemingly endless. And now, introducing our new and improved Proof® powered by Always styles—updated with even higher absorbencies so you can take on your period week with peace of mind.  

To find the best absorbency level, follow these guidelines:  

  • Light: Holds up to 1 regular tampon. 
  • Moderate: Holds up to 5 regular tampons. 
  • Super Heavy: Holds up to 7 regular tampons. 
  • Overnight: Holds up to 9 regular tampons.  

All of our absorbency levels offer ultra soft comfort and come in a wide range of cute styles. 

Style & Fit

Made with buttery-soft fabric, our period underwear is super comfy. Designed for all-day comfort, every pair features multi-way stretch fabric that moves with you. Moral of the story is if you love comfort, you'll love our underwear.

Yes! While you should not wear the same pair of underwear every day, it is safe to wear a fresh pair of period underwear every day. Proof® created a line of period underwear called the Everyday Collection explicitly designed for everyday use. The Leak-Resistant Everyday Brief helps protect you from daily leaks and is so comfortable and stylish that it feels like a second skin. The everyday undies are made with comfy materials that move with your body while you exercise or run errands.

The right size can contribute to your comfort. Refer to our size guide which can be found on each product page for our sizing recommendations. Remember though, the right size will be what you feel best in.


For washing and drying our period underwear, we recommend the following method of care to maximize use. 

1. Wash 

All of our undies are machine washable. We recommend washing on a delicate cycle with cold water with delicate detergents. And if you prefer, you can hand wash them, too. 

2. Dry  

For our Proof® powered by Always styles, you can toss them right in the dryer!  

For our classic Proof® styles, hang or lay flat to dry. Expect our classic Proof® undies to take between 6-24 hours to dry. To expedite the drying process, blot excess moisture and hang dry. Stock up to make sure you are always covered. 

3. Go 

The best part about Proof® is that you get to keep wearing them again and again! Our Proof® undies were designed for years of wear, so you can keep enjoying the feeling of worry free periods! 

Washable underwear for periods are made to wear and wash, not wear and toss. Our period underwear is leakproof and available in a variety of absorbency levels. Choose the right absorbency level depending on your flow—whether it’s day or night—and move freely in soft period underwear. For reference, here's an overview of our absorbency levels and the protection they can provide. 

· Proof Light Absorbency Period Underwear 

Holds up to 1 regular tampon 

· Proof Moderate Absorbency Period Underwear 

Holds up to 5 regular tampons 

· Proof Super Heavy Absorbency Period Underwear 

Holds up to 7 regular tampons 

· Proof Overnight Absorbency Period Underwear 

Holds up to 9 regular tampons 

Find your flow by absorbency levels

Period underwear is a form of protection you can wear throughout the day and throughout the night. Therefore, stock up to ensure you always have the protection you need. When determining how many pairs to order, think about when you will use them. We see many of our customers use them for overnight, their super heavy days, and so on! Use that as a starting point. Beyond that, determine how many days you would want to wear Proof® undies. Reference our leak levels to determine how many pairs of each kind will best meet your needs. 

There's also a good chance you'll love our leakproof underwear, period or not. With the ability to protect for all types of leaks, you may want to fill your entire underwear drawer with leakproof underwear. You've heard the old saying: better to be safe than sorry. Take us up on our bundle discounts and stock up on our buttery soft leakproof underwear!  

If you forget to separate your classic Proof® underwear from the rest of your washing and it gets thrown in the dryer, don’t panic. One or two trips through the dryer aren’t going to make them unusable. 

However, like your bras, while they can survive the dryer, you shouldn’t do it on purpose if you want them to last. The special materials in period underwear can become damaged quickly by repeated runs in the dryer. 

Remember, Proof® powered by Always undies are all washer & dryer friendly so it makes your laundry day that much easier. 

Absolutely! As mentioned above, Proof® underwear is totally machine washable. Just make sure you wash your undies in cold water on a delicate cycle.

Customer Service

While we try to keep our shelves well-stocked, sometimes a style is so popular that it sells out! 

If you're loving a style that's out of stock, you can sign up for alerts to be notified as soon as more inventory arrives. Choose the style, color, and size you would like, and select 'Notify When In Stock' then enter your email address and phone number to be alerted as soon as your favorites are back in stock! 

Our 60 day money-back guarantee is our way of saying, we know you’re going to love Proof® undies - but, if for whatever reason you are unsatisfied or our products do not meet your expectations, you can return them within 60 days for a full no-questions asked refund! The 60 day money-back guarantee is for all first time orders only.

*60 days from the time of receipt of order.

Click the link below and enter your Order Number or Email to begin you return.

Start Your Return