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.
Image of a absorbancy surrounding text
Holds up to 10 tampons or pads worth of blood.
Image of a moisture fabric surrounding text
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: 70% Nylon, 30% LYCRA®

Gusset Top Layer: 84% Modal, 8% Seaweed Fiber, 8% Spandex

Gusset 2nd Layer: 100% Polyester

Gusset 3rd Layer: Leakproof Technology

Free from PFAS and other chemical treatments.

Machine wash cold with mild detergent. Do not bleach. Lay flat to dry.

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 Canada please allow 2-4 business days for shipping to the GTA, 3 - 10 business days for urban areas, and 6-15 business days for remote locations.  

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

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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.

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.

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.

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.

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.

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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COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
ABSORBENT
JUST PLAIN BETTER
REUSABLE
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