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New Innovation

Leakproof Invisible Cotton No-Show Brief

$32.00 CAD

Buy 3+ Save 15%, Buy 5+ Save 20%

Soft cotton-blend fabric

Invisible under clothes

Moderate leakproof protection

High-rise, full coverage

Color: Periwinkle Limited Edition

Size:

True to Size

•

Size:

Size and Fit Guide

Leakproof Underwear is Sales Tax Free in Canada*

Build Your 3-Pack

Leakproof Invisible Cotton No-Show Brief

Color: Periwinkle Limited Edition

Size:

Size:

Leakproof Invisible Cotton No-Show Brief

Color: Periwinkle Limited Edition

Size:

Size:

Leakproof Invisible Cotton No-Show Brief

Color: Periwinkle Limited Edition

Size:

Size:

Free Shipping on orders $125+

Shipping

Shipping

Processing Timelines

Please allow 1-2 business days for our warehouse team to pack and ship your order. During peak periods such as sales, holidays and product launches, please allow up to 4 business days for us to process your order.

Delivery Time

For the most up-to-date delivery time estimates, please refer to the shipping timeline at checkout. Delivery timelines vary depending on location and do not include processing times.

Shipping Charges

Orders over $125* CAD = Free Shipping (2-6 business days)

Orders under $125* CAD = $12 CAD Shipping (1-3 business days)

Orders delivering to NWT, Nunavut and Yukon are subject to $20 delivery fee.

*After discounts, before shipping and taxes.

First Pair Risk Free for 30 Days

Leakproof Underwear, Risk Free

Returns & Exchanges

Holiday Return Policy
Eligible items purchased online or in stores between November 2, 2026 and December 31, 2026 may be returned through January 29, 2027. All other purchases fall under our 30 day Returns Policy.

Standard Return Policy
New to leakproof? Your first pair is risk free for 30 days. Wear them, wash them, and see how they work for your body. Not right for you? We'll refund the item price (original shipping excluded). Prefer a different size or style? We also offer free exchanges. Just email info@knix.com and we'll take care of you.

Purchased leakproof before? Within 30 days of delivery you can exchange for another size, style, or store credit. We're unable to provide refunds on underwear. If you ordered multiple pairs, please open, wash, and wear one pair only before initiating an exchange.

Still have questions? View our full policy here.

Rewards Members Earn 32 Points

Product Description

Introducing our softest cotton-blend underwear, upgraded with invisible seam construction and built-in leakproof protection. The Leakproof Invisible Cotton No-Show Brief features a comfortable high rise and full coverage designed to stay smooth under any outfit. Crafted with a cotton-blend body and a discreet leakproof liner that absorbs about 2 super tampons for all-day confidence. Perfect for everyday period backup, light bladder leaks, and sweat protection.

High-Rise, Full Coverage

Designed with an elevated rise and full bum coverage for a secure, supportive feel.

Invisible, No-Dig Finish

Innovative bonded seam design lays flat against your skin for a no-show finish under clothing.

Moderate Absorbency

Absorbs about 2 super tampons worth of liquid—great for moderate flow days, light bladder leaks, and sweat.

Soft Cotton Blend

Made with a soft cotton-blend body fabric for the everyday comfort you love.

Zoom

How to Choose?

Essential

  • • Days you don’t need leak protection. Everyday freshness and moisture wicking.
  • tsp
    0 tsp

Heavy

  • • Extra peace of mind. For the first days of your cycle, light bladder leaks, or a full night's sleep without a leak.
  • tsp
    about 8-14 tsp
  • pad
    about 1.5-3 regular pads
  • tampon
    about 4-7 super tampons
  • cup
    about 1.5-3 menstrual cups

Light

  • • Daily freshness. For sweat, discharge, period spotting, or backup protection.
  • tsp
    about 1-3 tsp
  • pad
    about 1-3 pantyliners
  • tampon
    about 1-3 regular tampons
  • cup
    about 0.5 menstrual cups

Moderate

  • • For mid-cycle flow, surprise cough or sneeze leaks, or a really sweaty spin class.
  • tsp
    about 4-8 tsp
  • pad
    about 1-1.5 regular pads
  • tampon
    about 2-4 super tampons
  • cup
    about 0.5-3 menstrual cups

Ultra

  • • Ultimate peace of mind. For the heaviest period days, light bladder leaks, unexpected postpartum flow, or overnight protection.
  • tsp
    about 15-20 tsp
  • pad
    about 1.5-2.5 super pads
  • tampon
    about 7-11 super tampons
  • cup
    about 2-3 menstrual cups
OUR NEWEST INNOVATION IS HERE

COTTON. SEAMLESS. LEAKPROOF.

Impossible. Until now.

Cotton-Blend Comfort

Soft cotton-blend fabric delivers natural softness and the familiar, all-day comfort of your favorite everyday underwear.

4.2
Rated 4.2 out of 5 stars
Based on 37 reviews
76%would recommend this product
ComfortRated 4.1 on a scale of 1 to 5
EffectivenessRated 4.3 on a scale of 1 to 5
FitRated -0.3 on a scale of minus 2 to 2
Keywords
Keywords
Rating
Ratings
Height
Height
How do you use your Leakproof?
How do you use your Leakproof?
Usual Pant Size
Usual Pant Size
37 reviews
  • Rated 5 out of 5 stars
    12 hours ago
    Comfortable underwear

    I bought 5 pairs of leakproof briefs and they are very comfortable and fit well. I am usually a L size but I needed to size up to XL as for me the L size was a little tight. Very happy with my purchase and will be buying more. I highly recommend.

    VS
    Vikki S.
    Verified Buyer
  • Rated 5 out of 5 stars
    Yesterday
    Favorite

    These are the favorite of the three different styles I’ve tried. I can’t figure out how to determine just what “style” they are. They fit best and are the most comfortable. I will order them again if I can figure out what to call the style - how to identify exactly this one!

    SK
    Sharon K.
    Verified Buyer
  • Rated 5 out of 5 stars
    Yesterday
    Really like these

    Really liking these cotton briefs. Will be grabbing more of these. So comfortable.

    NH
    NANCY H.
    Verified Buyer
  • Rated 5 out of 5 stars
    2 days ago
    Cotton

    Good fit

    NB
    Nancy B.
    Verified Buyer
  • Rated 5 out of 5 stars
    3 days ago
    First time buyer

    I was skeptical but I was wrong. I really like these. I have skin issues with regular panty liners. These eliminate them all together. Thanks!

    BD
    Brenda D.
    Verified Buyer
  • Rated 5 out of 5 stars
    6 days ago
    very grood

    works well

    comfortable

    DK
    Dorothy K.
    Verified Buyer
  • Rated 5 out of 5 stars
    6 days ago
    Leakproof

    Comfortable

    SR
    Sharon R.
    Verified Buyer
  • Rated 5 out of 5 stars
    1 week ago
    Very comfortable

    Most comfortable underwear ever.

    HN
    Helena N.
    Verified Buyer
  • Rated 5 out of 5 stars
    1 week ago
    5 Stars

    Quality

    T
    Trina
  • Rated 5 out of 5 stars
    1 week ago
    Great for light days

    Feels like regular underwear and very breathable.

    KG
    Kathy G.
    Verified Buyer
  • Rated 5 out of 5 stars
    1 week ago
    New Undies

    Very comfortable and true to size

    LK
    Linda K.
    Verified Buyer
  • Rated 5 out of 5 stars
    2 weeks ago
    Very Happy

    I first purchased Knix multiple years ago. Have not needed to replace them until now. The fabric and design has changed since my original purchase but very happy with them. Can't testify to how well they hold up but so far, so good!

    AH
    Andrea H.
    Verified Buyer

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