Period underwear (also known asmenstrual underwear orperiod panties) areabsorbent garments designed to be worn duringmenstruation, as an alternative or backup to other menstrual products. Period underwear is designed like conventionalunderwear but it is made up of highly absorbent fabrics to soak up menstrual blood. Most commercially manufactured period underwear makes use ofmicrofiberpolyester fabric. It is recommended that period underwear should be changed at least once every 8-12 hours to ensure optimal hygiene and comfort.[1]
The market for period underwear has developed as a response to consumer preference moving away from traditionalmenstrual hygiene management products, such assanitary pads andtampons.[2] Different brands use different, oftenpatented, technology for anti-microbial action, moisture-wicking[3] and optimal absorption.
Julie Sygiel[4] was cited by theBBC in 2015 as an early developer of the technology, with her company 'Dear Kate'.[5]
Period underwear is considered to be aneco-friendly way to cut down on waste[6] and reduce spending.[7] It is estimated that the disposal of menstrual products generates 200,000 tonnes ofplastic waste in theUnited Kingdom each year.[8][9]
Nancy Redd, a writer forThe New York Times, described the product's features: "some menstrual-underwear styles are gorgeous but leaky, and others haveHoover Dam–level security but diaper-like silhouettes. The style that will be best for you depends on your period flow and preferences".[10]
Some manufacturers of period underwear are extending their ranges into other leak-proof clothes such asswimsuits,sportswear andsleepwear.[11]
In the United Kingdom, period underwear was subject tovalue-added tax at 20% until 2024, despite the fact that other menstrual products wereexempted from the tax in 2021.[12] The exemption for period underwear was brought in aftertampon tax campaigners petitioned for the tax to be removed.[13]
Some companies (likeThinx, Ruby Love, and Knix) are facingclass action lawsuits for period underwear products that contain potentially harmful toxins likeper- and polyfluoroalkyl substances (PFAS) which may be linked to adverse health outcomes likecancer.[14] Thinx settled a lawsuit in January 2023 but made no admission of guilt or wrongdoing in the settlement.[15] Some brands of period underwear have been found to containsilver used as anantimicrobial agent. Concerns have been raised about the possible health impact of silver migrating into the body, but limited research has been done and little scientific data exists.[16]