Cotton Super Leakproof Boxer Brief

Ultra-soft cotton boxer brief featuring extra leg length and our longest super leakproof gusset ever. Absorbs up to 10 tampons or pads worth of blood!

First layer: Moisture-wicking, antimicrobial technology wicks away sweat and moisture while neutralizing odors to keep you fresh all day long. 

Second layer: A super thin, highly-absorbent liner that holds the power of 10 tampons or pads.

Third layer: A secure, liquid-resistant outer layer keeps leaks from happening.

the most requested underwear in our lineup.
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Holds up to 10 tampons or pads worth of blood.
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Rapidly absorbs moisture to keep you fresh and dry all day.
Antimicrobial layer kills bacteria and neutralizes smells.
Designed with a longer gusset for front-to-back coverage.

Ultra-soft cotton boxer brief featuring extra leg length and our longest super leakproof gusset ever. Absorbs up to 10 tampons or pads worth of blood!

First layer: Moisture-wicking, antimicrobial technology wicks away sweat and moisture while neutralizing odors to keep you fresh all day long. 

Second layer: A super thin, highly-absorbent liner that holds the power of 10 tampons or pads.

Third layer: A secure, liquid-resistant outer layer keeps leaks from happening.

Body: 47% Cotton, 47% Modal, 6% Spandex

Gusset Top Layer (Moisture Wicking + Anti-Odor): 84% Modal, 8% Seaweed Fiber, 8% Spandex

Gusset 2nd Layer (Absorbent Fabric): 100% Polyester

Gusset 3rd Layer (Hydrophilic + Waterproof): 100% Polyester

Gusset 4th Layer (Waterproof Membrane): PU Film

Free from PFAS and other chemical treatments.

Machine wash cold with mild detergent, do not bleach, tumble dry on low.

*For hygiene reasons all underwear are final sale.

Because they’re, well, underwear—we can’t accept exchanges or returns on used items BUT you can try your first-pair on your first order, risk-free!  

What's First-Pair Risk-Free?  

If your first order includes multiple period underwear: OPEN, WASH & WEAR ONE PAIR ONLY to test them out. That way, in the unlikely event that you don’t love them, any unopened packages from the same purchase can be exchanged or refunded back to you within 30 days of delivery (excluding original shipping fees).  All unopened packages will be donated to local organizations to support people in need.

We ship our items via DHL, or Canada Post depending on your location. Please allow 1-2 business days for your order to dispatch.  

For orders to the US please allow 3-10 business days for orders to arrive. For international orders please allow 10-25 business days.  

Please note: orders placed on Friday after 1 pm will not be processed until the following Monday.   

CANADIAN CUSTOMERS: shop www.knixteen.ca to order in Canadian Dollars!

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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION

KT by Knix Period Underwear FAQs

Super Absorbency
A total replacement for disposable period products - absorbs approximately 8 tsp, 40 ml, or the equivalent of 8 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.

Our 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.

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 pad 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.

Washing your period underwear shouldn't be complicated, so we designed our products to be super easy to wash and care for. For best results, machine wash on cold with mild detergent and tumble dry on low (Super Leakproof Underwear). That's it! Pro tips: Don't use softener or bleach and never iron.

If you want help finding the perfect Period Underwear product size for you, connect with one of our expert Knix team members for a 1-on-1 fitting session over video chat. Book a time that’s convenient for you, and we’ll walk you through everything!
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We have a First Pair Risk-Free Return Policy for your first order - no ifs ands or buts! So if you ordered the wrong size of Period Underwear, we’ll send you a different pair at no cost or offer you a standard refund within 30 days of delivery (excluding original shipping fees).

If your first order included multiple Period Underwear: OPEN, WASH & WEAR ONE PAIR ONLY to be sure you love them. That way if you don’t, any unopened packages from the same purchase are also eligible for an exchange or standard refund (excluding original shipping fees).

All unopened packages will be donated to local organizations to support people in need.

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Sustainable
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Absorbent
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Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
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