Thinx is machine-washable and reusable period-absorbing underwear — providing a more sustainable alternative to single-use disposable products. Thinx underwear for periods is designed in a range of absorbencies, from lightest to super, to support every stage of your flow. Every pair of Thinx period-absorbing underwear features our signature, innovative built-in technology — a moisture-wicking top layer, an absorbent core layer, and an outermost leak-resistant barrier. Check out our How Thinx Work page to learn more.

Our absorbent styles hold from 1 regular tampon worth of flow to 5 regular tampons worth, so there is a style right for each day of your cycle. We recommend trying Thinx period-absorbing underwear for the first time at home to see how each underwear style works with your ~flow~.

Every flow is different! You can wear Thinx underwear for periods for as long as your flow allows. The absorbency style also plays a factor, as some underwear styles are more absorbent than others.

We recommend following the hip measurement to find the most accurate size. Be sure to measure your hips at their widest point, derrière included! We recommend sizing up in underwear styles that fit below the natural waist, or if you're looking for the best fit postpartum. The underwear should fit snugly but not so tight that it becomes uncomfortable.

Our sustainable period underwear is super easy to care for. Machine wash the undies with the rest of your laundry on a cold cycle before first wear and after each use. Steer clear of fabric softener and bleach. Hang dry to keep your undies at maximum performance. Do not iron.

We offer a 45-day trial on all orders, so if you’re unhappy with your purchase, we’ll try to make it right. Final sale items, Thinx “merch”, and gift cards are nonrefundable. Visit our online Returns Portal to begin a return or exchange.