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This leading period underwear brand has a branch specifically for teens


Kt by Knix period undies have been tested by over 280,000 teenage girls, and come in multiple absorbency levels for all cycle phases


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Josie O'Brien
Josie O'BrienCreative Content Writer
September 5, 2025
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We’re in a new era of period management. Gone are the days of only having pads and tampons to choose from, and here are the days of modern and more comfortable ways to deal with your menstrual cycle. And if you weren’t already aware, the standout trend leading this revolution is period underwear. Designed to be worn as regular undies whilst absorbing your flow (as well as preventing leaks and odor), they're washable, and thus reusable, and can last up to three years. 

When it comes to industry leaders in period underwear, Knix is the name to know. Launched in 2013 with a leakproof technology that the lingerie market had never seen before, the brand has since sold over 15 million pairs of undies. Most customers purchase five or more pairs at a time. The styles come in multiple absorbency levels to support every phase of your cycle, and in cuts that suit every body shape

Period underwear isn’t just for us seasoned women, either. In 2017, the brand launched Kt by Knix, a dedicated line for teens and tweens. This branch was created to offer a safe and empowering introduction to periods. Think of Kt like the confident younger sister of Knix, existing to support young girls as they become familiar with their menstrual cycle. 

model posing in bathroom © Kt by Knix
Period underwear brand Kt is the sister company of industry leader, Knix

“I founded Knix to radically transform the intimates industry,” says founder and president Joanna Griffiths. “Frustrated by the lack of innovation in underwear – especially for people dealing with leaks – I invented leakproof underwear and pioneered a new product category. Guided by real customer feedback, a commitment to inclusivity, and a mission to break taboos, I built Knix into a brand that celebrates the freedom to live unapologetically free.”

With the same patented leakproof technology as Knix, Kt underwear has been tested by over 280,000 youngsters. These pants, which come in the form of briefs, thongs, boxers and even active-wear shorts, have been thoughtfully designed based on real feedback from young girls. In addition to the Knix Fund, Kt is active in school and youth-based organizations to make tweens and teens' first periods a positive experience.

teenagers stood in school gym by basketball rack© Kt by Knix
Kt by Knix is active in school and youth-based organizations to make periods a positive experience for young girls

We all remember our first bleed, and some of us definitely wish that period pants had been an option during those unchartered times in our lives. As such, we’ve put together our top picks of Kt by Knix period underwear to help ease every young girl into the world of periods. Each pair has a built-in liner that absorbs blood, with absorbency categories of light, moderate and heavy so you can find the right pair for your teen’s needs.

These are our top Kt by Knix picks...

  • Model in Kt by Knix Super Leakproof Sleepover Short

    Super Leakproof Sleepover Short

    Kt by Knix

    The details

    • Holds about 5.5 super tampons' or 2.5 regular pads' worth of blood
    • Designed with a longer gusset to prevent leaks all night long
    • Rapidly absorbs moisture for night-long freshness and dryness
  • Model wearing Kt by Knix Super Leakproof No-Show Underwear Bikini

    Super Leakproof No-Show Underwear Bikini

    Kt by Knix

    The details

    • Holds the same amount of blood as about 3 super tampons
    • Rapidly absorbs moisture to for dryness and freshness all day
    • Allows air to circulate to keep you cool and dry
  • Model in Kt by Knix Active short

    Leakproof Active Short

    Kt by Knix

    The details

    • Absorbs about 2 super tampons’ worth of blood
    • Stretchy, comfortable and true to size with four inch inseam
    • Discreet liner suitable for running laps in gym class and other sports
  • Model wearing Kt by Knix Super Leakproof Sleepover Boxer

    Super Leakproof Sleepover Boxer

    Kt by Knix

    The details

    • Absorbs about seven to nine super tampons worth of blood
    • Super soft bamboo blend fabric
    • Extra long liner to prevent leaks
  • Model wearing Kt by Knix Leakproof UltraThin No-Show Thong

    Leakproof UltraThin No-Show Thong

    Kt by Knix

    The details

    • Absorbs about three regular tampons worth of blood
    • Rapidly absorbs moisture to keep you fresh and dry all day
    • Allows air to circulate to keep you cool and dry


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