TikTokers Are Wondering Whether It's "Gross" to Keep Underwear Longer Than 6 Months

A viral TikTok claims you should throw out your underwear every six to nine months. Here's what ob-gyns have to say about this supposed rule.

When was the last time you threw out your old underwear? If you're struggling to remember, first of all, same. But apparently, some people on TikTok think you need to toss your skivvies roughly twice a year.

In early March, TikTok user @kittychemist shared a now-viral video claiming you should throw out your underwear every six to nine months because "not all bacteria, pathogens, and fibers can be removed during washing."

"For the longest time, I didn't know this at all until I had to find out for myself," @kittychemist said in a subsequent TikTok. "About five years ago, I kept getting these recurring infections. I couldn't figure out why. I went to see a gynecologist, I talked to my mom about it, we changed a lot of stuff in my diet, and nothing would help."

During one of her trips to the ob-gyn, @kittychemist said her doctor asked what kind of underwear she uses. She said she wears "a whole blend of stuff," including cotton underwear and lacey thongs. "That's how we found the cause of the infection," continued @kittychemist. She said her doctor told her that, after years and years of wearing certain fabrics, it's likely that the material won't be "completely free and clear of bacteria" that can cause an infection — even if you're washing said underwear after each use. (

@kittychemist noted that this was her own personal experience, one that might not ring true for everyone. Naturally, though, several other TikTokers are mind-blown by her revelations.

In one video, TikTok user @karla0487 says she's "very concerned" by the notion that underwear should be thrown every six to nine months, admitting that she feels "gross" for holding on to hers much longer than that. "I want to know that there are other women out there in the world that are with me," she says before hilariously explaining "the lifetime of underwear" in her house: First, she says she buys new underwear, washes it before wearing it, and then wears it for five years (washing between each wear, of course). "Yes, you heard properly," she quips. After that point, she continues, she typically reserves that older underwear for when she has her period (#relatable). Once they've been "upgraded" to period underwear, @karla0487 says she usually keeps them for "around 10 more years." So, overall, her underwear gets around 15 years of use. (

Plenty of people in the comments agreed with @karla0487. "I keep [my underwear] until a hole appears. The hole tells me when it's time," wrote one commenter. "I replace them when they start falling apart," said another. "I pretty much wear them until they disintegrate," joked another commenter.

Fellow TikTok user @ashleight819 shared a similar video. "I mean, honestly, my underwear just gets to a certain point and it levels up to period panties," she says in her TikTok. "I think I have underwear that's probably a decade old. Am I the only one?"

Basically, it seems that a lot of people are confused about how often you should actually swap out your underwear. Here's what ob-gyns have to say about it.

Do you need to throw out your underwear after six to nine months?

For the record, none of the ob-gyns Shape spoke to have even heard of this supposed underwear rule. "That's news to me," says Mary Jane Minkin, M.D., a clinical professor of obstetrics and gynecology and reproductive sciences at Yale Medical School.

There's also no official guidance from the American College of Obstetricians and Gynecologists (ACOG), the ruling body of ob-gyns in the U.S., on how often you should throw out your underwear. Christine Greves, M.D., a board-certified ob-gyn at the Winnie Palmer Hospital for Women and Babies in Orlando, Florida, says she even tried searching scientific literature for something — anything — to support this claim. While a 2001 study published in the Journal of Infection suggests there might be about one-tenth of a gram of fecal matter (aka poop) on the average pair of "clean" underwear, Dr. Greves says using very hot water during your wash cycle should kill any of that lingering bacteria.

So, from a medical standpoint, throwing out your underwear every six to nine months isn't something you need to do, "as long as you're washing them after each use," says women's health expert Jennifer Wider, M.D. And, if you do keep your underwear for longer than six months, it won't automatically lead to a yeast infection or any other vaginal health issue, says Jessica Shepherd, an ob-gyn in Texas.

However, as @kittychemist noted in one of her TikToks, "there are certain materials that are not as breathable as others" and, as a result, may increase the risk of infection or other vaginal health issues, says Dr. Shepherd. "Cotton and bamboo blends are often the best, and then synthetic fabrics, such as polyester and spandex, can contribute to increased moisture, which can increase the risk of yeast infections and bacterial vaginosis," she explains. But, again, this isn't about how long you wear them — it's the type of fabric, stresses Dr. Shepherd. (

Some people like to toss their underwear after a yeast infection, adds Dr. Greves, but she says there's no necessary medical reason for that either — again, as long as you're washing said underwear after each use, she explains.

how often should you get new underwear

So, how often should you replace underwear?

Doctors say it's really up to you. "As long as the underwear is clean, it shouldn't cause an issue," says Dr. Shepherd. FWIW, "clean" means the underwear has been through a hot cycle in your washing machine with soap or has at least undergone a solid hand-washing with soap and hot water to help kill yeast and bacteria that could be lurking on the fabric, explains Dr. Greves. So, even if your underwear has a visible stain, that's OK — it doesn't necessarily qualify it as "dirty," as long as your underwear has been well-washed, she adds.

But, Dr. Shepherd says, if you're struggling with regular yeast infections, it's a good idea to switch to cotton underwear overall since it's more breathable and better for your vagina (and, of course, touch base with your ob-gyn about how to treat or manage the infections in general). Then, you can use that underwear 'til it falls apart, she says — whether that takes six months, nine months, or even several years. (

Once underwear starts to fall apart or lose elasticity, it won't necessarily hold on to more bacteria, but "it may not fit right or may not offer support," says Dr. Wider. For that reason alone, she says, "you can throw them away and buy a new one."

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