Super Leakproof Boyshort

Highly absorbent (and very cute!) boyshorts with added coverage, featuring our patented, 3-layer leakproof technology built 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 tampons.

Third layer: A secure, liquid-resistant outer layer keeps leaks from happening.
school. sofa. sleep. you’ll wear these period undies everywhere.
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Holds up to 8 tampons or pads worth of blood.
Thin, subtle, and designed to feel just like regular underwear.
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Rapidly absorbs moisture to keep you fresh and dry all day.
Antimicrobial layer kills bacteria and neutralizes smells.

Highly absorbent (and very cute!) boyshorts with added coverage, featuring our patented, 3-layer leakproof technology built 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 tampons.

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

Main Body: 70% Nylon 30% Spandex 

Gusset Top Layer (Moisture Wicking + Anti-Odor): 87% Seaweed Fiber; 13% Modal  

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

Gusset 3rd Layer Fresh Fix Technology 

Gusset 4th Layer (Waterproof Membrane): Polyurethane Film   

Free from PFAS and other chemical treatments.  

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

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.  

FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
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.



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
Reviews
average rating 4.7 out of 5
Based on 266 reviews
  • 5 Stars
    217 Reviews
  • 4 Stars
    36 Reviews
  • 3 Stars
    8 Reviews
  • 2 Stars
    2 Reviews
  • 1 Star
    3 Reviews
97% of reviewers would recommend this product to a friend
Quality
Rated 4 out of 5
Comfort
Rated 4 out of 5
Sizing
Rated 0 on a scale of minus 2 to 2, where minus 2 is Fits Small, 0 is True to Size and 2 is Fits Large
Effectiveness
Rated 4 out of 5
266 Reviews
Reviewed by Alex
I recommend this product
Rated 5 out of 5
Review posted

These Work.

I was suspicious this underwear would meet its claims - holding about 8 tampons worth?! But OMG! This underwear WORKS. On my heaviest days, I’ll wear these from morning until bedtime and have never had one leak. I was literally SHOCKED! Even better they feel completely dry all the time! The only thing I’d say is they seem to fit slightly smaller than KT’s regular oh-no proof underwear, so I’d recommend going up a size.

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Reviewed by ANJELICA B.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Astonished

I purchased these for my teen. She started her period at a young age so I feel like we've tried every pad under the sun to find something that was comfortable and "didn't look like a diaper". Our biggest concern were the night leaks/overflow but I have to say, Knix did the job! I didn't expect for them to do so well! I was astonished! No leaks, no overflow. My daughter was very happy which makes me happy.

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Reviewed by Rebecca F.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Excellent for heavy period

My daughter has only had 3 periods, and they are Monstrously heavy. I had ordered the normal period underwear in preparation for her getting her period and they were no match, but these new heavy flow ones are excellent! Thank you!!!

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Reviewed by Andrea L.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Reliable comfort

My daughter thinks these are so comfortable and don’t have a visible panty line even with her yoga tights . They hold everything they are supposed to without any leaks. She is a believer!

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Reviewed by Fernanda
Verified Buyer
I don't recommend this product
I'm A...
Adult
I purchased for...
Myself
Pant Size
Teen 4-10
Size Purchased
L
Usage
  • Back-up Protection
Rated 2 out of 5
Review posted

Inconsistent sizing

I really wanted to love these! I ordered three panties (two Super Leakproof Boyshort and one Leakproof Boyshort) and even though I utilized the chart and read the reviews to help me get the correct size, they are too big. I did wait to get my period to see if I would be bloated and then the panties would fit, but they were still too big, especially the Super Leakproof Boyshort! Definitely disappointed. As reference I'm 137lb, 5'04', hips 39, I ordered the Large size and is way too big.

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Quality
Rated 5 out of 5
Comfort
Rated 3 out of 5
Sizing
Rated 2 on a scale of minus 2 to 2, where minus 2 is Fits Small, 0 is True to Size and 2 is Fits Large
Effectiveness
Rated 3 out of 5
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