For the perfect fit, don’t take a wild guess — take your hip
measurement! Standing with your feet together, wrap a soft
measuring tape around the widest part of your lower hip.
| 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 |
The fabric for our BASE undies is designed to have a snug fit
that moves with you. If you're between sizes, we recommend
trying the larger size for BASE.
Aisle BASE period undies feature a specially-engineered lining that combines super-absorbent Truetex™ technology with a leak-proof layer to keep you dry and feelin’ fly.
No detectable levels of PFAS have been found in our underwear, based on a detectable limit of one part per million
Our period underwear are designed to be worn on their own, but they make great backup protection for a tampon or menstrual cup too!
Rinse the gusset in cool water before washing in the machine with your regular laundry. Hang to dry where possible - it saves energy and prolongs the life of your undies! Just make sure they’re fully dry before storing or reusing.
We kept it super simple and streamlined with BASE undies, so you can just put 'em on and go. There are no pockets in the gusset of BASE undies so there's no need to use Aisle Boosters.
