Adjustable Absorbency
BOOST Brief
BOOST Brief
Includes one removable Booster that lets you increase the absorbency on heavy flow days, or dial it back for light flow days. Holds 4 regular tampons without Booster and 8 regular tampons with a Booster.
Details
Details
● Best for heavy flow and long hours thanks to our easy swap Booster
● Made with a buttery soft blend of TENCEL™ and organic cotton for an ultra comfortable feel
● Holds up to 8 regular tampons with Booster
● Machine washable and dryer safe
● B Corp Certified sustainable and ethically made
● Leakproof, breathable, and PFAS-free (no detectable levels up to 1PPM)
● Sales Tax Free in Canada
● FSA/HSA accepted at checkout in US
How Do Period Underwear Work?
How Do Period Underwear Work?
Period/leakproof underwear works by using a combination of absorbent and waterproof layers to trap and lock in menstrual flow. The top layer wicks away moisture and keeps you dry, while the inner layers absorb liquid and the leakproof layer prevents leaks. Designed for comfort and performance, Aisle period underwear can be worn alone or as backup for other period products.
Materials
Materials
Body: 48% TENCEL™ lyocell, 48% organic cotton, 4% spandex
Gusset: 90% Truetex™ (88% recycled polyester, 12% organic cotton), 10% TPU
Lining: 86% recycled polyester, 14% organic cotton
Booster: 65% recycled polyester, 24% polyester, 11% hemp
All materials are OEKTO-TEX certified and lab tested for PFAS. No detectable levels of PFAS to 1 part per million.
Underwear Size Guide
Standing with your feet together, wrap a soft measuring tape around the widest part of your lower hip. If you're between sizes, we recommend sizing down.
| Hip | Waist | Size | |
| XXS | 33-34" | 23-24" | Y14-00 |
| XS | 35-36" | 24-25" | 0-2 |
| S | 37-38" | 26-27" | 4-6 |
| M | 39-40" | 27-29" | 8-10 |
| L | 41-42" | 30-32" | 12-14 |
| XL | 43-44" | 33-35" | 16-18 |
| 1X | 44-46" | 37-39" | 16-18 |
| 2X | 48-50" | 41-43" | 20-22 |
| 3X | 52-54" | 45-47" | 24-26 |
| 4X | 56-58" | 49-51" | 28-30 |
| 5X | 60-62" | 53-55" | 32-34 |
See it in your size
BOOSTED
Each pair of Aisle Boost underwear can hold up to 4 tampons’ worth of flow on its own, plus 4 more with the removable booster. For heavy flow, just tuck in the Booster and swap it out as needed. No more mid-day undie changes!
FAQ
How does the Booster work?
Boosters allow you to customize the absorbency of Boost period underwear to meet your needs. They also allow you to refresh your period protection throughout the day, without changing your underwear.
On light flow days, wear Boost undies without the Booster for 4 tampons worth of protection.
On heavy flow days, tuck a Booster into the slits at each end of the gusset, and swap them out throughout the day for 8 tampons worth of protection.
Do Aisle period underwear contain PFAS?
We do not add PFAS to any of our products. In addition to using OEKO-TEX certified materials, which are tested for the presence of PFAS, we also conduct additional third-party tests. No detectable levels of PFAS have been found in our underwear, based on a detectable limit of one part per million.
Do I need to wear a pad or tampon with Boost period underwear?
Nope! Boost undies were built to completely replace pads and tampons. Just swap out the Booster as needed throughout the day. Worn without the Booster, they can also be worn as backup protection with a tampon or menstrual cup.
I have heavy flow. Are these the most absorbent period underwear?
Boost undies are adjustable-flow period underwear that can accomodate light to heavy flow, providing up to 8 tampons worth of absorbency. For heavy flow, add the removable Booster and swap it out as needed during the day.
Looking for an all-in-one heavy period undie? Try our Super period underwear.
How do I wash period underwear?
Our period underwear were made to fit into your regular laundry routine. Just rinse the gusset in cool water before washing in the machine with your regular laundry. Avoid the use of fabric softener and bleach, as they can inhibit absorbency and cause the leakproof material to break down. Our undies are dryer safe, but we recommend hanging to dry where possible - it saves energy and prolongs the life of your undies!
Love the fit and the material
I've used these for 2 months and so far, I'm impressed! I'm 125lbs and the S fits really well, with great coverage across the bum. I like how they are dryer safe and get fully clean in one wash. Other brands I've used have not seemed to be coming fully clean with one wash.
I love the boost brief, this pair of period underwear leaves me feeling protected and comfortable. I had previously tried the retro brief but didnt love the limited coverage. I perfer my underwear fabric come a little higher up than what the retro brief did in the front.
I will definitely give it that Aisle is the best period underwear that I and my daughter have tried. We have tried a lot, at least seven or more brands. These are soft, stretchy and the best part is they can be washed and dried like normal. That is a huge plus. They are true to size. I am between a 3x and 4x....same in these.
My favorite is the boost brief. I found the overnight boxer do not fit my body well and that did cause an issue for me. I want an overnight panty but they only have the boxer. I really want a booster brief with higher protection in the back and even front for back and front sleepers. They are great for daytime but not nighttime. Most period panties I tried had the protection go much higher in the front and back, so that is a disappointment. The other thing I hope they change is the width of the gusset. Specifically for the plus side. The gusset is not wide enough for larger women. I have had it move over too much and not have enough coverage, causing a leak in a restaurant where I am still mortified and not sure I can ever go back. Along with it moving again in my car and now I have a big stain.
Ad long as I am careful that it doesn't move, then they are fine. But now with this two mishaps, it is making me more nervous to go with just the period panty without a pad as a backup and that feels like it defeats the purpose for me. I would expect others to have the same issue. So I am hoping they change the width of the gusset.
Change those two things and I think the panty is perfect. Oh and add an overnight brief.
Super comfy and they feel super secure throughout the day.