Foot odors are a common problem, but one most people are too embarrassed to talk about. That’s too bad, because there are some easy fixes.

Imagine you’re on a cramped bus. It’s stuffy and hot, and your feet feel like they’re roasting. You really want to take those sneakers off, but you just can’t.

Human feet contain roughly 250,000 sweat glands, more per square inch than anywhere else in the body, according to the Royal College of Podiatry in the United Kingdom. When sweat accumulates inside socks and shoes, bacteria break it down and cause that bad odour.

Smelly feet aren’t a hygiene problem, though. It doesn’t mean you don’t shower frequently enough. Instead, it’s usually a moisture problem.

One simple fix may already be sitting in your bathroom cabinet.

“Standard antiperspirants will block the sweat glands and prevent the sweat from forming on the skin,” said Karl Landorf, professor of podiatry at La Trobe University in Australia. The same aluminium salts that block sweat ducts in the underarms also work to reduce moisture in feet, limiting the conditions that can cause odour and blisters.

But most people don’t think to try it.

Studying why feet smell

In one military experiment, more than 300 cadets were asked to apply antiperspirant to their feet before a 20-kilometre (12.4-mile) hike. Those who used it for several nights beforehand had fewer foot blisters than a placebo group, though they reported more skin irritation.

“Sweating, no matter where it occurs in the body, is to aid cooling,” Landorf said. “The problem is that the feet usually have socks and shoes surrounding them, so the sweat can’t evaporate easily.”

Bacteria on the skin then feed on the sweat and produce acids that create that familiar smell. In some people, around 10 to 15%, certain bacteria produce sulphur compounds that worsen the smell.

Some people also just sweat more. Excessive sweating, known as hyperhidrosis, can affect specific areas of the body, including the hands and feet, or even the whole body.

It affects around 2 to 5% of people and is more common in younger adults. Despite how common it is, only about half of people ever discuss it with their doctor, according to research published in the Archives of Dermatological Research.

In some cases, profuse sweating can be a sign of something serious, such as infections or hormonal disorders, so it’s worth getting checked out, according to the International Hyperhidrosis Society.

Combatting foot odour

Antiperspirant powders allow for good application to all parts of the feet, including between the toes, and are kinder to the environment than sprays using propellant, Landorf said.

Roll-ons and creams can also be used, but each has its trade-offs and can be more difficult to apply evenly between the toes.

The pharmaceutical company Bayer used to sell an antiperspirant named Prantal Powder, whose active ingredient was diphemanil methylsulfate, an anticholinergic agent also used to treat peptic ulcers.

Landorf said it worked by blocking the signal that tells the sweat glands to produce sweat. But Bayer discontinued the product in 2017.

In Australia, Drital and Neat Feat 3B powders are marketed to prevent chafing, reduce perspiration and limit odour. Drital contains diphemanil methylsulfate, the same ingredient once used in Prantal Powder, along with corn starch and zinc oxide.

Neat Feat 3B contains zinc oxide and aluminium chlorohydrate, one of several aluminium salts commonly found in underarm antiperspirants.

Overcoming embarrassment

In North America, foot powders usually focus more on absorbing moisture and controlling odour than on blocking sweat directly.

Whether applying antiperspirants to feet is worth trying depends on the severity of symptoms and individual preferences, Landorf adds, and clinicians should work with patients to address their aims.

Some people may be embarrassed by even mild symptoms and want to treat them aggressively. “That’s fine as there are usually very few side effects,” he said.

“The best advice is to follow the instructions carefully on the product packaging,” he said. Usually once a day is sufficient. If the sweating is bad enough, over-drying is unlikely and it’s rare to get irritation.

Further non-surgical treatments include Botox injections and iontophoresis, which involves immersing the feet in water while a mild electric current is passed through it, but these would be reserved for severe cases, Landorf said.

Questions to consider:

1. Why do you think people are embarrassed about body odours?

2. What are some ways people can prevent foot odours?

3. Can you think of a problem you have that you are too embarrassed to talk about with people?