Leakproof Boyshort

Stretchy, seamless 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.

Made for doing everything or nothing on your period. Your pick.
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Holds up to 3 tsp (or 3 tampons or pads) worth of blood.
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Rapidly absorbs moisture to keep you fresh and dry all day.
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Thin, subtle, and designed to feel just like regular underwear.
Antimicrobial layer kills bacteria and neutralizes smells.

Stretchy, seamless 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.

Body: 77% nylon, 23% LYCRA® 

Gusset Liner: 86% cotton, 10% spandex, 4% carbon 

Gusset: 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.  

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 4.8 out of 5
Based on 737 reviews
  • 5 Stars
    607 Reviews
  • 4 Stars
    102 Reviews
  • 3 Stars
    14 Reviews
  • 2 Stars
    7 Reviews
  • 1 Star
    7 Reviews
96% 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
Fit
Rated 0 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
737 Reviews
Reviewed by Kayla M.
Verified Reviewer
I recommend this product
Rated 5 out of 5
Review posted

A REVIEW FROM AN 11 YEAR OLD

Hey! I'm Kayla and I'm 11! My mom is a nurse and wanted me to be prepared to have my first period, so she got me these. (Bikini's but now I wear boyshorts) This was a lifesaver! I have my period at school and I didn't know and when I went to the bathroom I was able to put on a pad! It saved me from leaking and getting blood all over. It's super comfy and it is very stretchy and breathable. The packaging is also a pencil case, makeup bag etc. It can also be used as a heating pad and comes with cute stickers. You put hot damp/wet face towels and it stays hot for a long time! The heating pad works very well! I would highly recommend these to everyone! There are literally no downsides.

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Fit
Rated 0 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
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Reviewed by Allayna W.
Verified Buyer
I recommend this product
Rated 4 out of 5
Review posted

Good quality

I tried the Knixteen line after finding the women's sizing to be a touch too large for my frame.

Ordered a size L in these and they fit much better. I prefer the overall style of the bikini-type bottoms better but in terms of fit, these are far superior. I actually find that these boyshorts fit snugly and don't move around, which is exactly what one wants with period underwear!

For reference I'm 5'3 and about 125 pounds. If you have a small frame, go for either a size Large or even a Medium in the Knixteen line if you find the regular sizes a touch too large!

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Fit
Rated 1 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
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Reviewed by Donna H.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Great product

I have 12 year old twins. One loves these boy shorts, but she has heavy periods, so wears a pad with them. The other is very petite and live the bikini. She has light periods, so the bikini ones are perfect for her without a pad.

I highly recommend!! I will add, they run pretty small. My bigger gal wears a woman’s size 6 and the boy shorts in large are perfect. My petite size 10 in kids clothes wears the medium bikini, but can also wear the large in a pinch.

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Rated -2 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
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Reviewed by Alyssa
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Great for Menstrual Cup Users!

I am a woman in my 30s, and find these to be SO helpful! I changed over to a menstrual cup a few years ago due to my concern about environmental waste. But i was still encountering issues with leakage on my heaviest days, and was annoyed I still had to purchase pantyliners in addition to using the cup. No more with these boyshorts and bikinis! I have removed that extra waste from my life, and feel confident and protected when wearing these at work during my heaviest days now! Game changer!!!

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Fit
Rated 0 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
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Reviewed by Nguyen
Verified Buyer
Rated 3 out of 5
Review posted

Sizing guide could be more helpful

I am 87 lb 4'9" adult. My hip measurement is 24 / 25 so I ordered 2 of the boybriefs in small. The fit is very tight on thighs and butt so that my circulation feels cut off making them impractical for exercise. They are thin and otherwise look amazing. Haven't had the chance to bleed in them. Was excited that there is Knixteen since regular Knix sizing is too large for me but I wish the sizing chart accounted for more body types such as curvy and athletic. I've already spent $30+ and have nothing I can use.

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