Hold your nose - a new study has found half of Americans don't change their underwear every day.
The disturbing statistics were revealed by underwear maker Tommy John, which surveyed 1000 Americans.
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It found 45 percent wore the same pair of underwear for two days or longer - with 13 percent saying they had worn the same pair for a week or more.
"Conventional wisdom - and basic common sense - tells us that we should change our underwear every day, or at least wash them after every wear," Tommy John said on its website.
"But how many people actually follow this golden rule? After surveying 1,000 Americans, we found that this basic standard of underwear hygiene is definitely not universal."
Perhaps unsurprisingly, men are the ones skimping on changing their underwear. The survey found men are 2.5 times as likely as women to wear their underwear for a week or more - that's 20 percent of men versus 8 percent of women.
Tommy John also found people are loyal to their underwear, with 46 percent of those surveyed saying they owned the same pair of underwear at least one year.
The company advises replacing them often due to "problematic microorganisms and fungal germs".
"It's crucial to update your underwear wardrobe every six months to a year to ensure you're protected from harmful infections and health risks," Tommy John said.
"Women should be especially careful, as they're more at risk than men to experience health issues due to unclean underwear."