How Often Should You Get New Underwear?

It's a given that you should change your underwear at least daily and wash them before wearing the same pair again. But what about the lifespan of your underwear? 

From a health perspective, is there an optimal point when tossing your old ones and getting a supply of brand-new underwear is necessary? The answer isn't as simple as you'd think, Taraneh Shirazian, MD, a board-certified gynecologist at NYU Langone Health, told Health. 

Here's what you should know about how often you ought to purchase new underwear to maintain good vaginal health.

What the Experts Say

As of December 2022, no research says that wearing old underwear is unhealthy or a risk factor for any vaginal complications, explained Dr. Shirazian. But in terms of comfort and reducing the odds of any issues—like an allergic reaction or infection—it may help to replace your underwear regularly.

Philip Tierno, PhD, clinical professor of microbiology and pathology at the NYU Grossman School of Medicine, told Health that underwear doesn't have an expiration date. 

Still, Tierno added that there are some signs that you should retire them. For instance, if your underwear is mechanically dysfunctional—or, in other words, they have holes or the elastic is gone—it's time to replace them.

What Happens When You Wear Old Underwear

The risk isn't very high, but worn-out underwear might pose health problems. If a pair doesn't fit properly, they might seal in the moisture that would typically be wicked away, leading to vaginal infections.

And if the seams of your underwear become frayed, they might irritate your skin. That irritation may result in cuts or abrasions that increase your risk of infection.

Fabric Type Makes a Difference

In some cases, the type of fabric your underwear is made of matters as much as its state. Specifically, Dr. Shirazian recommended wearing cotton underwear. The cotton material is breathable and doesn't allow moisture to build up. 

On the other hand, synthetic fabrics like nylon and Spandex hold in moisture and don't dry quickly, boosting your irritation and infection risk. Tight-fitting underwear and pants can also increase moisture in the genital area, upping your chances of recurrent vaginal infections.

"When choosing underwear for the first time, be aware of things like natural materials and dyes and chemicals," suggested Dr. Shirazian.

The fabric of your underwear also matters when it comes to cuts. Fancy lingerie might consist of stiff material that can cut into your genital area, which isn't just uncomfortable but might set you up for abrasions. 

For daily use, choosing comfy, soft underwear that absorbs moisture may be helpful—whether they're granny briefs, boyshorts, bikinis, or thongs.

Thongs Aren't the Enemy

Contrary to popular belief that thongs are more likely to cause infections than other underwear styles, some evidence suggests that they don't carry a high risk. 

In one study published in 2018 in the Journal of Obstetrics and Gynaecology Research, researchers found that the rates of urinary tract infections (UTIs), bacterial vaginosis (BV), and yeast vaginitis (YV) were not higher among those who wore thongs compared to others.

UTI, BV, and YV are among the most common vaginal infections. The researchers found that sexual behaviors and hygiene choices are more likely to influence the risk of those infections than your underwear choice.

So, whether you're wearing thongs or boyshorts, it's essential to use good hygiene and wash them correctly to eliminate bacteria. You could also reduce wear and tear by buying more pairs, so you use each one less.

Also, changing your underwear frequently is essential. According to one study published in 2018 in BMC Women's Health, women who changed their underwear more often were less likely to have yeast infections than others.

Expert Tips for Washing Underwear So It Lasts

It's essential to clean your underwear properly between wears to avoid health risks. You may also save yourself the bother of frequently replacing frayed or worn underwear.

First, follow the care instructions on the label. Also, Tierno suggested adding bleach to your wash cycle if you wear white cotton underwear.

"[Bleach] will take care of all the bacteria," said Tierno. If your panties are dyed, you can add other products, such as Lysol, to a hot water cycle instead of bleach. Also, many washing machines have a germicidal cycle, meaning you don't have to use an additional germ-busting product.

"This cycle raises the temperature far beyond what you could achieve with ordinary hot water," explained Tierno.

If your underwear is made of delicate fabrics, such as silk or acetate, you'll want to wash them by hand. You can also put them through a cycle designed for delicates. But you'll still want to use products that ensure a deep clean.

The drying process also helps kill bacteria in the dryer or hanging out in the sun for a blast of ultraviolet (UV) radiation.

A Quick Review

There's no hard rule for how often you should buy new underwear. But it may help to purchase new ones when yours aren't worn enough to irritate your genital area or if they're trapping infection-causing moisture.

When you do buy new undies, consider cotton because the fabric is less likely to trap moisture, and you can bleach it for extra germ protection.