Best Period Panties for Heavy Flow
Most of us have a “heavy day” in our cycle. But some women get it in spades. They soak through tampons and pads, stain bedding and clothing and are always on “high alert” during their period. And that’s without even talking about the cramping and pain that can accompany heavy bleeding.
The good news is that period underwear can protect even heavy flow. Unlike normal underwear, Knix’s super absorbent range of period underwear is designed to completely replace disposable products. But, of course, you can use it in tandem with other products… whatever works for your flow!
What to Look for in the Best Period Underwear for Your Heavier Days
No matter what brand you’re shopping from, here’s what to look for in the best period underwear to help manage your heavy flow:
Absorbency You Won’t Second-Guess
Yep, it’s all about absorbency. You want to focus on products that will give you super absorbency. But even for women with heavy flow, there’s likely a “lighter” day. So you can consider a product for heavy or even medium flow on those days.
The key is to help you feel confident, so err on the side of caution. When you’re starting out and gauging the right level, try using your new underwear as a backup while you develop confidence in them. In no time at all, you’ll realize what works for your unique flow.
Moisture-Wicking & Odor Control
Heavy flow doesn’t just create overflow concerns. It also can mean the awkward feeling of sitting with “soggy” panties or waking up in the night to damp and stained bedsheets.
To help avoid that wet swimsuit feeling, you want to look for technical fabrics that will wick moisture away from the body and contain it. To complement that, also look for odor control.
Comfort and Coverage, Without Bulk
When I first started hearing about women wearing period underwear, I pictured adult diapers. It seemed near impossible that underwear could do the job of pads or tampons without being bulky.
And while that couldn’t be further from the truth, you probably will feel better protected with underwear that gives you a little more coverage on your heavier days.
I'm a big fan of boyshorts for precisely this reason. They’re still light-as-air and give that invisible look and feel. But they also offer a safe barrier between my body and my clothes which mitigates fears of extreme leaks that you would have with regular underwear.
Your Choice of Period Underwear Styles
While the boyshort is my personal favorite (for both period underwear and regular underwear), you shouldn't be shackled to a single style of period underwear. Indeed, just as with regular undies, wearing period underwear should present a wide variety of style choices. Period underwear styles can include thongs, bikini style, high rise briefs, boyshorts and much more
The Best Period Panties for Heavy Flow: Knix Picks
Naturally, we think you can’t go wrong shopping from any of our Super Leakproof range of products. However, if you’re asking us to pick favorites, these are our top picks for heavy-flow period underwear:
Best Period Underwear Overall: Super Leakproof Boyshort
Everybody has their favorite style of period underwear, but for us, you can’t beat the boyshort. It’s cute, casual and sexy and offers great coverage without the seams. Our Super Leakproof Boyshort provides solid leak protection! So you can switch from relying on disposable products to wearing incredibly comfortable and machine-washable boyshort underwear that will protect you every day of your cycle!
How it fits:
Extra coverage through the hip and bum, and sit slightly higher than our bikini silhouette. The ultra-thin & absorbent gusset is 9” long, providing confident coverage in the front and behind. The fabric is designed to feel snug at first but relax with wash and wear for a perfect fit.
What reviewers say:
“The boy short is my favorite of all of the knix panties. They stay put and are more of a low cut brief, not a "short". I wear these on my heavier days and they work surprisingly well. I love reducing the excess waste and not having to deal with pads and tampons. I'll never go back. Thank you, Knix.”
“Bought these period panties for my daughter, who has the dreadfully heavy teenage flow. She absolutely loves them. She said they are so soft and super absorbent and she doesn’t feel any wetness on her skin. Time to stock up. My only complaint...Where were these when I was a teenager?!”
Size options:
XS to XXXXL, and everything in between.
Best Thong: Super Leakproof Thong
The Super Leakproof Thong is a solid choice! Switch from relying on disposable products to wearing incredibly comfortable and machine-washable underwear.
How it fits:
The thong provides a mid-rise silhouette with minimal bum coverage. The ultra-thin & absorbent gusset is 8-9” long, providing confident coverage in front and behind. The fabric is designed to feel snug at first but relax with wash and wear for a perfect fit.
What reviewers say:
“I can't believe I waited so long to give these period panties a try. They work great, they look good, and they're super comfortable -- absolutely NO bulky pad/diaper feeling & NO soggy feeling between your legs. I purchased a few super leakproof thongs & a few regular leakproof ones, and I was pleasantly surprised by how well these did their job. I was able to get thru my entire workday without having to think about my period, and that's a beautiful thing. I will NEVER be going back to disposables, that's for sure!”
“Finally a thong I can wear with confidence! This is the first thong I've found that offers more than 'light protection'. The colour, style, fit is perfect. It's so comfortable. I need more!”
Size options:
XS to XXXXL, and everything in between.
Best Period Panties for Sleeping: The Super Leakproof Dream Short
The Super Leakproof Dream Short is a super-comfy sleep bottom with built-in coverage featuring our patented leakproof technology.
How it fits:
The Dream Short is designed to comfortably hug your body and stay in place overnight, you can wear it as a pyjama bottom or underneath your regular sleep get-up.
What reviewers say:
“One heavy night per month... I never slept well because I was worried about leaking through to the sheets and I slept on a towel that night. These dream shorts are awesome and alleviated all of my concerns. I slept GREAT and these shorts did their job!”
“I bought two pairs of the dream shorts to wear at night while on my period. It was SO nice going to bed not worrying about what position I was laying in or if I would wake up to a leak on the sheets! I’ve worn them now through two periods and I couldn’t be happier that I finally decided to try them.”
Size options:
XS to XXXXL, and everything in between.
Best for Every Day of Your Period: Heavy Flow Period Kit
Get confident protection for your whole cycle - even your heaviest days - with our Heavy Flow Period Kit. This kit includes:
- 4 pairs of Super Leakproof Period Underwear
- 1 pair of Dream Shorts - our comfy and confident sleep short designed for overnight period protection.
Absorbency level:
- Super Absorbency: A solid replacement option for disposable period products.
- High Absorbency: Ready to stop higher flow leaks
What reviewers say:
“My period comes hard and fast and so the Heavy Kit is perfect for me. I hated having to wear maxi pads all time and even felt a little embarrassed sometimes. I finally feel comfortable and confident on my period even though I'm a heavy bleeder. Thank you Knix!”
Size options:
XS to XXXXL, and everything in between.
Best for Gentle Shaping: CoreLove High Rise
Beauty meets function with the CoreLove High Rise, an innovative high rise leakproof underwear. Velvet compression bands help give your core some extra love, support, and stability. And an extended gusset featuring our patented leakproof technology gives you absorbent protection.
How it fits:
Sits at the natural waist and provides medium coverage through the bum. Features an extra long gusset.
What reviewers say:
“Really helps with endo cramps.”
“These period panties are absolutely incredible! I got my period today and I normally have fairly bad cramps on the first day. I put these on and they have helped my cramps so much I have not even needed to take medicine to get through it today! So good. They are less stretchy and a little harder to get on because of the core love band but so so worth it! 10/10 would recommend!”
Size options:
S to XXXL, and everything in between.
Frequently Asked Questions About Knix Period Underwear
Why Should I Switch to Period Underwear?
Here are three compelling reasons to switch to period panties:
1. Period Panties Reduce Waste:
According to National Geographic: “A typical menstruator will use anywhere from 5 to 15 thousand pads and tampons in their lifetime. Most of that ends up in landfills.”
Whether you use pads or regular tampons, applicators or not, periods can create a lot of waste. Even if you don’t wholly eliminate tampons or pads, using them on fewer days will have a positive impact on our environment.
2. They Save You Money
Disposable period products are notoriously expensive. Indeed, according to the Canadian Public Health Association, “It is estimated that Canadian women spend up to $6,000 in their lifetime on menstrual hygiene products (Craggs, 2018). Women in rural communities can pay double the price for the same products found in larger cities, such as Toronto (Brown, 2017).”
And while the initial expenditure for period panties is more, over time you can make significant savings.
3. Comfort!
Many women find tampons uncomfortable and pads bulky. Period panties or underwear can offer you a natural and comfortable “second skin” feeling. You definitely shouldn't have to settle when looking for comfortable period underwear—a wide variety of styles and absorbency levels means you should be able to fine the best period underwear for YOU!
Don’t take our word for it! We’ve heard it from multiple reviewers and fans. Just check out the reviews on any of our product pages!
What Do the Different Knix Period Underwear Absorbency Levels Mean?
Most period underwear from any brand will indicate a level of absorbency. At Knix, we use the following absorbency levels for our period underwear. You may be tempted to think that “super absorbency” is the best period underwear. And this is certainly the case for heavy flow days. But most of us have lighter days too! Ultimately, the best level is the one that makes you feel most confident and secure.
- Super Absorbency: A replacement option for disposable period products.
- High Absorbency: Heavier flow protection.
- Medium Absorbency: Confident backup protection for medium flow days.
- Light Absorbency: Protection for your lighter days.
Do I Need To Wear a Pad, Tampon, or Menstrual Cup With Period Underwear?
This is a personal choice. Depending on the level of absorbency of leakproof period underwear you choose and the heaviness of your flow, you can wear our period panties on their own or as backup protection along with menstrual cups or tampons.
However, you can also choose to completely ditch your tampon or menstrual cup: You're fully protected with our high and super-absorbency leakproof underwear. Our low and medium-absorbency leakproof underwear can replace pads and tampons on lighter days and work great as a backup for your usual period protection on heavier days.
How Do I Wash Period Underwear? Yes, You Can Machine Wash!
Washing your leakproof underwear shouldn't be complicated, so we designed our products to be super easy to wash and care for. For best results, machine wash on cold with mild detergent, and either tumble dry on low (Super Leakproof Underwear) or lay flat to dry (all other Leakproof products). That's it! Pro tips: Don't use softener or bleach and never iron.
Is Period Underwear Breathable? Can It Give Me an Infection?
Our Leakproof Underwear uses moisture absorbing materials in the gusset liner. However, you should also make sure to change out of sweaty clothes and to always wash them between wears.
Written by Jane Flanagan — Updated on April 16, 2023.
We hope you found this post informative — but remember: we’re not doctors and this post is not medical advice! While all posts are fact-checked and well researched, we always recommend you chat with your doctor about any questions or concerns you might have regarding a medical condition. We’re here to support and educate, but never with the aim of disregarding professional medical advice you’ve been given. Phew, now that that’s out of the way, you can go on living unapologetically free.