I'm a pharmacist - millions make huge underwear mistake without realising

It's something most people don't think twice about, but the contents of your underwear drawer could be harbouring a hidden hygiene problem. New research has revealed that millions of Brits are clinging on to their underwear for years beyond its best-before date, with experts warning that this seemingly harmless habit could be quietly increasing the risk of infections, irritation and other health issues.

Lingerie brand Pour Moi found that the average oldest pair of pants in UK drawers is an eyebrow-raising two years and seven months old, with more than one in six adults (16%) admitting they still wear underwear that's over five years old. While that might sound harmless, pharmacist Ana Carolina Goncalves warns that old underwear can become a breeding ground for bacteria and yeast. Over time, fabric fibres break down, making it easier for microbes to linger even after washing. That build-up, she explains, can lead to issues such as thrush, skin irritation, bacterial vaginosis, and even urinary tract infections (UTIs).

"Bacteria can begin growing on underwear almost immediately after wearing it," Goncalves says. "Tight styles, long days, or lots of activity can make this worse, especially for people who naturally produce more bacteria due to their genetics or lifestyle."

The study also revealed another worrying trend: nearly three in ten (29%) Brits admit to wearing the same pair of pants more than once without washing them. That's the equivalent of over 13.8 million adults walking around in less-than-fresh underwear at any given time.

Goncalves explains that re-wearing without washing gives bacteria time to multiply. "You shouldn't wear underwear for more than a single day before washing it - any use beyond this increases microbial accumulation and risk of infection," she says.

Even the washing routine itself can play a part. Certain bacteria can survive if clothes are washed at low temperatures, particularly under 30°C. Using detergent and washing after every wear helps eliminate most microbes, but experts recommend regular hot washes where fabric allows.

Despite 79% of people admitting that some of their underwear is showing signs of wear and tear, only 31% actually consider those items to be damaged.

According to lingerie specialist Emma Woodrow from Pour Moi, many of us are simply reluctant to let go of our favourite pairs, even when the signs are obvious.

"If your pants are losing shape, feel less supportive, or are starting to look faded or marked, it's probably time to replace them," Woodrow says.

She adds that regular checks are key - particularly for the pairs you wear most often - and recommends refreshing your most-worn underwear every 6-12 months, depending on how frequently they're used and what activities you wear them for.