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First Period Prep

You can't predict her first period. You can prepare for it. You can't predict her first period. You can prepare for it.

First periods can be unpredictable. Give her one less thing to worry about with leakproof underwear that looks and feels like regular underwear.

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Free period undies when you spend $120

Your leakproof questions, answered.

What is Leakproof underwear and how does it work?

What do the different underwear absorbency levels mean?

Ultra Absorbency

Absorbs the equivalent of 7-11 super tampons. Our longest front-to-back liner, designed for their heaviest flow days and overnight protection.

Heavy Absorbency

Absorbs about the same as 4-7 super tampons. Perfect for overnight protection or your teens heaviest days when changing into a fresh pair might not be convenient.

Moderate Absorbency

Absorbs about 2.5 super tampons' worth of blood. Ideal for medium period days, discharge and sweat.

Light Absorbency

Absorbs about the same as about 1 regular tampon worth of blood, sweat or discharge. Ideal for lightest period days, spotting, sweat and discharge.

How does period swimwear work?

Our period swim bottoms have a triple-layer gusset that absorbs your flow and locks in leaks, in and out of the water. And when you throw them in the wash with detergent, everything releases through the top layer so your swimwear comes out fresh and clean. Your other clothes will be totally fine too, we promise.

Here's how the three layers break down:

Layer 1 is a silky-smooth top layer that sits right against the skin.
Layer 2 is a super absorbent middle layer built with our leakproof tech that holds up to 1–3 tampons worth of blood.
Layer 3 is a waterproof outer layer that prevents any leaks from showing through.

How do I wash period underwear?

It's easy, we promise. Give them a quick rinse under cold water first, then toss them in the washing machine with your regular clothes, cold water, mild detergent, no softener or bleach. For drying: lay flat for medium absorbency styles, or tumble dry on low for high and super absorbency ones. That's it. No ironing needed!

Does my teen need to wear a pad or tampon with period underwear?

Totally up to them! Every flow is different, and there's no wrong answer. Depending on the absorbency level and how heavy their period is, they can wear KT undies on their own or use them as backup alongside a tampon or menstrual cup. Whatever makes them feel most confident is the right call.

“My daughter had a seamless first period with her Kt underwear (I'm not crying, you're crying).”

-Jordan R., Verified Buyer, Super Leakproof® No-Show Boyshort

Shop Period Undies Take Our Underwear Quiz

“Worked perfectly! As expected, she got her period 1/2 way through camp. She said she spent every day in the lake without a worry!”

-Lori S., Verified Buyer, Period Swim Sport One-Piece

Shop Period Swim

“These shorts are so comfortable to sleep in! The extra long built in pad saved me from leaking. I could finally sleep comfortably on my period.”

-Linda P., Verified Buyer, Super Leakproof® Sleepover Short

Shop Sleepover Short

“These undies are the easiest for my tween to use; she likes them way better than pads or tampons. And I love that they're a reusable product.”

- Allison B., Verified Buyer, Leakproof UltraThin No-Show Boyshort 3-Pack

Shop Period Undies

LOVED BY TEENS. TRUSTED BY PARENTS.

Why leakproof?

Built-in protection that helps teens feel secure on their period. The science behind the #1 Leakproof Brand in North America.

Soft top layer

Comfy, super smooth moisture-wicking liner keeps you feeling fresh and dry.

Middle absorbent layer

Bottom leakblocker layer

How to wash

Why I started KT By Knix

Kt was founded in 2017 because we believe every teen deserves period products that make them feel as confident as possible.
‎

Joanna, Founder of KT by Knix

Learn More

Totally Not TMI

Kt Period Playbook Kt Period Playbook

There’s zero shame in teens wanting confidence, not confusion when it comes to periods.
That’s why we made this free guide and workbook just for them.

Get Your Free Digital Copy

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You can't predict her first period. You can prepare for it. You can't predict her first period. You can prepare for it.

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