Viral underwear 'survey' results spark debate: What happens if you don't change every day?

The internet decided to air its dirty laundry on Friday — specifically, its underwear.

The discussion began with a survey from apparel maker Tommy John, which made the bold (and, to many, upsetting) claim that “45 percent of Americans have worn the same pair of underwear two or more days in a row.”

The survey garnered a wave of reactions online, many of disgust. But polling experts quickly pointed out both the dubious methodology of the research (which simply claims to have “surveyed 2,000 men and women”) as well as the issues with an underwear company — which could benefit from underwear panic — funding it.

But while the survey — and its limitations — may be new, the topic of re-wearing underwear has long been a controversial one. So what exactly happens if you don’t change it every day? The truth is, the hygiene police won’t arrest you (though, if they existed, you should at least get a citation).

In fact, Philip Tierno, professor of microbiology and pathology at New York University School of Medicine, told HuffPost Life in 2018 that a person could get away with wearing the same pair of underwear for two days in a row without harming his or her health.

However, not all experts agree that it’s harmless. In 2017, Bustle ran a piece listing the six “gross and dangerous things” that can happen from wearing underwear two days in a row, including “bad odors,” “acne and skin problems” and “stains.”

For women, trapped sweat could pose another risk. Melissa Goist, an OB-GYN at The Ohio State University Wexner Medical Center, told Health in 2015 that bacteria and yeast "love to multiple in a warm and wet environment," meaning that re-worn underwear could led to yeast (or other) infections.

But even washed underwear isn’t as clean as you’d imagine: On average, clean underwear still contains about 0.1 grams of feces, according to a study in the Journal of Infection.

Americans also like to hold onto their underwear, apparently. A second Tommy John survey of 1,000 people found that 46 percent have owned the same pair of underwear for a year or more — and these results were split fairly evenly between men and women, according to the survey. Another 38 percent said they don’t know how old their oldest pair of underwear is.

But while retailers will tell you that you should replace underwear every six months to a year, Cora Harrington, founder and editor-in-chief of The Lingerie Addict magazine, tells Yahoo Lifestyle that’s just not so. “People should buy new underwear when their old pairs are ‘worn out,’ so to speak, and not according to any brand-suggested schedule like every six months,” she says.

Harrington adds: “Signs to watch for when it comes to replacing include a slackening of the elastic, bagginess in the fabric, stains that can’t be removed, and, of course, holes.”

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