Period underwear, also known as menstrual underwear or period panties, are absorbent garments designed to be worn during menstruation. They are designed like conventional underwear but are made up of highly absorbent fabrics to soak up menstrual blood. Most commercially manufactured period underwear makes use of microfiber polyester fabric. The fabric in period underwear contains a moisture-wicking fabric made up of thousands of small filaments. These fibers trap blood or other liquid to keep it from leaking onto your clothes. The outer layer usually includes nylon and Lycra, and is then finished with a liquid-repellent film.

Period underwear is considered to be an eco-friendly way to cut down on waste and reduce spending. It is estimated that tampons, pads, and applicators generate 200,000 tonnes of plastic waste in the United Kingdom each year. In the United States, it is estimated that sanitary products generate more than 200,000 tonnes of waste annually.

Period underwear can be worn on its own or for extra security while wearing a tampon, menstrual cup, or disc. Anyone with a period can use period underwear. But it’s important to know what to expect if you’re not used to free bleeding, which is a term used to describe when someone menstruates without the use of tampons or other common period products. Period underwear doesn’t stop the flow of your period blood. If you use it, you’ll feel the flow of menstruation, which can be unsettling for some people at first. Some women also use period underwear alongside other products, like tampons or menstrual cups, to add another layer of protection. But you can use period underwear by itself. Some brands come in different levels of absorbency, so you can choose a pair that works best for you on a particular day. Most pairs of period underwear are highly absorbent. But if your flow is heavy, it’s a good idea to check from time to time and see if you need to change them.

Period underwear is washable and reusable, which makes it more eco-friendly than single-use menstrual products. Different brands use different, often patented, technology for anti-microbial action, moisture-wicking, and optimal absorption. It is recommended that period underwear should be changed every 8-12 hours to avoid leakage and infection.