Blood, Sweat, Pee? No Problem

Leakproof Underwear have you covered. They look and feel just like normal undies, but feature high-tech, built-in protection. They’re the comfortable, confident, and convenient choice. And people everywhere are making the switch.

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Leakproof Best Sellers

Leakproof Underwear
It's time to break up with disposables and upgrade your period routine with life-changing Leakproof Underwear. From day to night, these are the most absorbent and comfortable undies you'll ever try.
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Leak-Free Activewear
We are pioneering Activewear with protection against leaks so you can focus on doing the things you love. Enjoy worry-free protection from blood, sweat or pee in our Leakproof Leggings, Shorts & Skort!
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Leakproof Swimwear
Get comfortable & confident on the beach or at the pool! These gorgeous suits are perfect to wear on their own or with your normal routine for worry-free relaxation in the sun.
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Non-Stop Absorbent Protection

No matter what you’re up to, your undies will be there to protect you. From Super Leakproof Underwear (absorbs up to 10 tampons worth of liquid) to the Leakproof Thong (about the same as 1), we’ve designed our underwear to wick away moisture and keep it from leaking through.

Anti-Odor Technology

The top layer of our liner is chemical-free, composed of natural fabrics that restrict the growth of bacteria. And that eliminates any odor between washes, so you can feel fresh and dry no matter what!

Just Like Normal Undies. But Better.

Our incredibly soft and stretchy fabric gives you the fit you want, without the bulk. And the built-in protection relaxes with wash and wear so that you barely even notice it. That’s kinda what makes them so special – you live your life, and leave the leaks to us.

★★★★★
“I’m never buying pads or tampons again! These are way more comfy and keep me totally dry.”

Laura H.

Find Your Perfect Pair

What’s Your Color?
Fun colors and limited-edition prints? Or classic black? Maybe something from a range of skin tones? We have the widest selection of colors for you!
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What’s Your Absorbency?
Whether you want help with period protection, bladder incontinence, or sweat, Knix has the perfect level of protection for you, no matter the level of leak.
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What’s Your Size?
With sizes ranging from XS to 4XL, we’ve made it a goal to make sure that more people in more sizes can make the switch to Leakproof Underwear.
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30-Day Wash & Wear Guarantee

All of our Leakproof Underwear are eligible for exchange only within 30 days of delivery. We want to make sure you can give your new Underwear time to adjust to your shape and get comfortable. Wear it, test it out, and wash it as much as you like. If you find the fit still isn't right, message us to get a personal fit consultation before exchanging for the right size.

Ditch the Disposables

Start cutting out single-use plastics for your own personal care. Knix Leakproof Underwear are reusable, machine-washable solution to protecting yourself from leaks in a more sustainable way.

Leakproof Period Underwear FAQs

Super Absorbency
A total replacement for disposable period products - absorbs approximately 8-12 tsp, 40-59-ml, or the equivalent of 8-12 regular tampons worth of liquid.

High Absorbency
Ready to stop leaks whenever - absorbs approximately 4-6 tsp, 20-30 ml, or the equivalent of 4-6 tampons worth of liquid.

Medium Absorbency
Confident backup protection for heaviest days - absorbs approximately 3 tsp, 15 ml, or the equivalent of 2 tampons worth of liquid.

Light Absorbency
Protection for your lighter days - absorbs approximately 1 tsp, 5 ml, or the equivalent of 1 tampons worth of liquid.

Depending on the size and style of underwear, the leakproof gusset ranges from around 7.5" to 9" long. Our Super Leakproof Underwear features a 25% bigger gusset, with more of the coverage in the front of the underwear. For overnight leakproof protection, our Super Leakproof Dream Short gusset ranges from 10" to 14" long.

Depending on the level of absorbency of Leakproof period underwear you choose and the heaviness of your flow, you can wear our period panties on their own or as backup protection along with a menstrual cup or tampon.

You're totally protected with our high and super absorbency Leakproof underwear, while our low and medium absorbency Leakproof underwear can replace pads and tampons on lighter days and work great as a backup for your usual period protection on heavier days.

Our Leakproof period underwear features triple layer technology that ensures you stay fresh, dry, and protected. The anti-odor top layer wicks away moisture from your skin; the inner-layer absorbs the liquid and locks it in; and the leak resistant outer layer keeps any liquid from spotting your clothes.

Our Leakproof Period Underwear feature barely-there built-in panty liners that can absorb between 1 and 8 tampons worth of liquid, providing you with confident protection against period leaks, light bladder leaks, and sweat.

Our Essential Underwear feature a moisture-wicking breathable gusset that keeps sweat and odor away, but they do not provide any leakproof protection.

Yes! Our period underwear is also the perfect protection against light bladder leaks (LBL). In fact, it was the frustrations and unnecessary stress of postpartum leaking that inspired our CEO Joanna to make her first pair of Knix.

If you're one of the 1-in-4 women who experience light bladder leaks, our incontinence underwear are here for you. They absorb up to 8 tsp of liquid and feature a moisture-wicking, anti-odor, and bacteriostatic properties to keep you feeling fresh, dry, and confident.

Super Leakproof Technology