Teen Leakproof UltraThin No-Show Bikini
Mix & Match: Buy 4+ Save 15%, 7+ Save 25%



Knix period underwear and pads are now sales tax-free in Canada.* We celebrate improvements to the accessibility and affordability of essential period care products.
Hanging out or running to your next class? These period undies provide the ultimate comfort you want, plus ultra-thin protection you need from sweat, discharge and leaks. It’s a classic silhouette made with a super soft-and-stretchy, quick-drying material. It absorbs about the equivalent of 2.5 super tampons for an extra dose of confidence on those medium-flow days.
Key Features:
- 360LeakSeal™ patented technology designed to seal in leaks from every angle
- Soft and stretchy for comfort throughout the day
- Seamless look for any OOTD
- Quick dry for that fresh feel
Body: 77% Nylon, 23% LYCRA® XTRA LIFE™Spandex;
Fresh Fix Technology®Gusset: Gusset 1: 86% Cotton, 10% Spandex, 4% Carbon; Gusset 2: 96% Polyester, 4% Spandex; Gusset 3: 83% Polyester, 11% Spandex, 6% Polyurethane
Additional Product Ingredient Information
🇨🇦 Free standard shipping over $100.
Free expedited shipping over $150.
(after discounts, before shipping + taxes) All items ship from within Canada.
Within 30 days of delivery, you may exchange for another size, style or store credit. We’re unable to provide refunds on underwear.
Kt by Knix for Teens Underwear FAQs
Kt by Knix is designed for smaller and growing bodies to fit teens. Kt Period Underwear are available in teen sizes with smaller leg openings.
Super Absorbency
Absorbs 9–12 tsp (45–60 ml) of blood—that’s about 9–12 regular tampons or pads! Perfect for overnight protection or your teens heaviest days when changing into a fresh pair might not be convenient.
High Absorbency
Absorbs 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
Absorbs up to 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, swimwear, reusable pads, and activewear have our patented leakproof technology built right in.
First Layer: Wicks away sweat and moisture while neutralizing odors to keep your teen fresh all day long.
Second Layer: A super thin, highly absorbent liner that holds the power of 3–20 tampons or pads.
Third Layer: A secure, liquid-resistant outer layer keeps leaks from happening.
The short answer: nope! Depending on the absorbency level of the period underwear and the heaviness of your teens flow, your teen can wear our period undies on their own or as a backup to tampons or menstrual cups. They can wear our High and Super absorbency underwear alone and be totally protected, while our Medium absorbency underwear can be worn alone on lighter days or as backup on heavier days.
- Kim S.Verified Buyer9 minutes agoRated 5 out of 5 starsGreat product!
These underwear provide protection just as stated!
ComfortRated 5.0 on a scale of 1 to 5Poor ExcellentEffectivenessRated 5.0 on a scale of 1 to 5Poor ExcellentSizingRated 0.0 on a scale of minus 2 to 2Runs Small True to Size Runs LargeWas this helpful? - Kim S.Verified Buyer10 minutes agoRated 5 out of 5 starsGreat protection!
These underwear do what they say they do! I can now go walking at a fast pace & not worry about leakage.
ComfortRated 5.0 on a scale of 1 to 5Poor ExcellentEffectivenessRated 5.0 on a scale of 1 to 5Poor ExcellentSizingRated 0.0 on a scale of minus 2 to 2Runs Small True to Size Runs LargeWas this helpful? - Jess P.Verified Buyer2 days agoRated 5 out of 5 starsWhere are my 40-something mamas?!
These are seriously the best leak proof underwear on the market. I’m 40 and after my third baby, my pelvic floor is a mess. While I’m getting PT I needed something to help during my HIIT workouts and my half marathon training and these are fantastic! I wish these were around when I was younger because I can definitely see how they support you during heavier day periods. I ordered a Medium and they fit perfectly but I’m a true medium and not in between sizes. If you’re on the fence about trying these out, I highly recommend! Thank you, Knix!
ComfortRated 5.0 on a scale of 1 to 5Poor ExcellentEffectivenessRated 5.0 on a scale of 1 to 5Poor ExcellentSizingRated 0.0 on a scale of minus 2 to 2Runs Small True to Size Runs LargeWas this helpful?