10k+ 5-star reviews

10k+ 5-star reviews & counting

There’s a reason 2 million+ people have switched to period underwear. With these new colors, your teen’s undies will make them feel confident inside and out.

10k+ 5-star reviews & counting

There’s a reason 2 million+ people have switched to period underwear. With these new colors, your teen’s undies will make them feel confident inside and out.

leader in leakproof for teens

Best Sellers

Heaviest Absorbency Yet

Super Leakproof® Sleepover Boxer

Heavy Absorbency

$45 ^USD Back in Stock

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+7
+3

Super Leakproof® Sleepover Short

Heavy Absorbency

$45 ^USD 2 for $39 EACH

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Best Seller

+2

Period Swim Sport One-Piece

Moderate Absorbency

$88 ^USD New Colors

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SELLING FAST

+6
+2

Light Leakproof No-Show Underwear Bikini 3-Pack

Light Absorbency

$60 ^USD $66 Save up to 15% off

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Period Swim Bikini Bottom

Moderate Absorbency

From $27.50 ^USD New Colors

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SELLING FAST

+7
+3

Leakproof UltraThin No-Show Underwear Boyshort 3-Pack

Moderate Absorbency

From $65 ^USD $72 Save up to 15% off

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UNDER-OUTFIT CONFIDENCE

Leakproof Shortie

Light Absorbency

From $39 ^USD

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FREE SHIPPING OVER $70

Our #1 selling overnight protection is back

You loved this overnight period solution for heavy flows so we brought it back in a new print. Get it before it’s gone (again).

Our #1 selling overnight protection is back

You loved this overnight period solution for heavy flows so we brought it back in a new print. Get it before it’s gone (again).

Machine Washable

Buy 3+ & Save

New Innovation + Absorbency

+1

Super Leakproof® No-Show Underwear Bikini

Heavy Absorbency

$27 ^USD 3+ for $25 EACH

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+4

Light Leakproof No-Show Underwear Bikini

Light Absorbency

$22 ^USD 3+ for $20 EACH

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+3

Leakproof UltraThin No-Show Underwear Bikini

Moderate Absorbency

$24 ^USD 3+ for $21.67 EACH

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+5
+1

Light Leakproof No-Show Underwear Boyshort

Light Absorbency

$22 ^USD 3+ for $20 EACH

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Leakproof Cotton Underwear Bikini

Moderate Absorbency

$22 ^USD 3+ for $21.67 EACH

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New Innovation + Absorbency

+1

Super Leakproof® No-Show Underwear Boyshort

Heavy Absorbency

$27 ^USD 3+ for $25 EACH

View

+3

Leakproof UltraThin No-Show Underwear Bikini

Moderate Absorbency

$24 ^USD 3+ for $21.67 EACH

View

New & improved heavy period protection

Our bestselling Super Leakproof® underwear is redesigned with improved leakproof layers for maximum protection and all-day or all-night comfort.

New & improved heavy period protection

Our bestselling Super Leakproof® underwear is redesigned with improved leakproof layers for maximum protection and all-day or all-night comfort.

Read The Rag

Free Period Guide

Everything your teen ever wanted to know about puberty, menstruation, and more.

Download the Guide

“With this new line, teens can lean into that life well lived from their very first period”

"KT by Knix is aimed at both helping teen girls deal with the reality of periods"

“KT by Knix products are simple and easy to use — you can wear them under absolutely anything”

KT Size	Hips	Kids Pant Size	Adult Pant Size
XXS	25” - 27”	7	---
XS	28” - 30”	8 - 10	---
S	31” - 34”	12 - 14	00 - 2
M	35” - 38”	16 - 20	4 - 8
L	39” - 42”	---	10 - 14
XL	43” - 46”	---	16 - 18
XXL	47” - 50”	---	20 - 22

KT Size	Band	Hips	Kids Pant Size	Adult Pant Size
XXS	23 ³/₄" - 25 ¹/₄"	25” - 27”	7	---
XS	25 ¹/₄" - 26 ³/₄"	28” - 30”	8 - 10	---
S	26 ³/₄" - 28 ¹/₄"	31" - 34"	12 - 14	00 - 2
M	28 ¹/₄" - 29 ³/₄"	35” - 38"	16 - 20	4 - 8
L	29 ³/₄" - 31 ¹/₂"	39” - 42”	---	10 - 14
XL	31 ¹/₂" - 33 ¹/₂"	43” - 46”	---	16 - 18
XXL	33 ¹/₂" - 35 ¹/₂"	47” - 50”	---	20 - 22

KT Size	Hips	Kids Pant Size	Adult Pant Size
XXS	25” - 27”	7	---
XS	28” - 30”	8 - 10	---
S	31” - 34”	12 - 14	00 - 2
M	35” - 38”	16 - 20	4 - 8
L	39” - 42”	---	10 - 14
XL	43” - 46”	---	16 - 18
XXL	47” - 50”	---	20 - 22

KT Size	Band	Hips
XS	28"	25” - 27”
S	30"	28” - 30”
M	32"	31” - 35”
L	34"	36” - 40”
XL	36"	41” - 44”
XXL	38"	45” - 48”

Size	Bust	Hips
XS	27”	25" - 27"
S	30”	28" - 30"
M	34"	31" - 35"
L	37”	36" - 40"
XL	40”	41" - 44"
XXL	40”	45" - 48"

Size	Hips	Height	Weight
XS/S	25" - 30"	4'2" - 5'1"	65 - 100 lbs
M/L	31" - 40"	4'9" - 5'6"	105 - 130 lbs
XL/XXL	41" - 48"	4'11" - 5'6"	135 - 170 lbs

Size	Under Bust (in)	Fits Cups
S	26 3/4” - 28 1/4”	A-DD
M	28 1/4” - 29 3/4”	A-DD
L	29 3/4” - 31 1/2”	A-DD

Best Sellers

Buy 3+ & Save

Absorbency Guide: Finding the Right Period Underwear for Your Teen