Period Underwear

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Moisture-wicking, odor-crushing, life-changing leakproof undies.


  • Black
  • Vacay Blue
  • Navy
  • Very Berry
Cotton Super Leakproof Boxer Brief
Super Absorbency
$42 CAD 3 for $111
  • Black
  • Dot Com
  • Plaidwave
  • Tie Dye Sky
  • Pride Unicorn
  • +1
Super Sleepover Short
Super Absorbency
$42 CAD 3 for $111
  • Plaidwave
  • Dot Com
  • Very Berry
  • Black
  • Beige
  • Tie Dye Sky
  • Swirly World
  • Periwinkle
  • +8
  • +4
Leakproof Boyshort
Medium Absorbency
$20 CAD Buy 3+ Save 20%
  • Black
  • Very Berry
  • Vacay Blue
  • Violet
Cotton Modal Super Leakproof Bikini
High Absorbency
$25 CAD Buy 3+ Save 20%
  • Dot Com
  • Plaidwave
  • Black
  • Beige
  • Tie Dye Sky
  • Periwinkle
  • Wild Child
  • Minty
  • +8
  • +4
Super Leakproof Bikini
High Absorbency
$25 CAD Buy 3+ Save 20%
  • Beige
  • Plaidwave
  • Dot Com
  • Black
  • Periwinkle
  • Tie Dye Sky
  • Minty
  • Wild Child
  • +7
  • +3
Super Leakproof Boyshort
Super Absorbency
$25 CAD Buy 3+ Save 20%
  • Very Berry
  • Plaidwave
  • Dot Com
  • Black
  • Beige
  • Swirly World
  • Periwinkle
  • Tie Dye Sky
  • +9
  • +5
Leakproof Bikini
Medium Absorbency
$20 CAD Buy 3+ Save 20%
Va Va Vibrant Period Kit
Medium - Super Absorbency
-
$105 CAD
Starter Set
Medium - Super Absorbency
-
$69.60 CAD $87 CAD
Heavy Period Kit
High - Super Absorbency
-
$115 CAD
Period Kit
Medium - Super Absorbency
-
$109 CAD
KT x DivaCup™ Period Kit
High to Super Absorbency
-
$88 CAD
nothing is tmi here—we promise.
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Super Absorbency

Absorbs up to 12 tsp (60 ml) of blood—that’s about 12 regular tampons or pads! Perfect for overnight protection or on your heaviest days when changing into a fresh pair might not be convenient.

High Absorbency

Absorbs up to 4-8 tsp (20-40 ml) of blood or the equivalent of 4-8 tampons or pads. These are perfect for heavy flow days.

 Medium Absorbency

These absorb approximately 3 tsp (15 ml) or about 3 tampons or pads worth of blood! Ideal for light to medium flow days or as backup to tampons or period cups.


All of our Period Underwear, Swim, and Activewear have our patented, 3-layer leakproof technology built right in—

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 3-12 tampons or pads.

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

The short answer: Nope! Depending on the level of absorbency of leakproof period underwear you choose and the heaviness of your flow, you can wear our period undies 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 to whatever you’re already using on heavier days.

Do a quick rinse before you throw your underwear in the machine. Wash on cold with mild detergent then tumble dry on low. That's it! Be sure not to use softener or bleach and never iron...not that you would.

If you’re not sure which size underwear to get, just book a Virtual Fitting and someone from the Knix team will video chat you to walk you through everything!

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!  

How it works:

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.