It seems counterintuitive—sandals are open and airy, yet they’re supposed to keep your feet cool. So why do they sometimes smell worse than sneakers after a workout? The answer lies in a combination of sweat, bacteria, and materials that don’t always play nice together.
Your feet have over 250,000 sweat glands, and they’re among the sweatiest parts of the body. When you wear sandals, especially in warm weather, your feet continue to sweat—sometimes even more due to sun exposure or walking on hot surfaces. Unlike socks, which absorb some moisture, sandals let that sweat pool and evaporate… but not before bacteria feast on it.
The real stink comes from that bacteria. As your sweat mixes with dead skin cells, the naturally occurring bacteria on your feet break everything down and produce odor-causing compounds, such as isovaleric acid. This process occurs more quickly in sandals made of rubber, plastic, or synthetic materials that trap heat and provide minimal ventilation to the sole of your foot.
Another overlooked culprit? Your sandals themselves. Over time, foot oils, dirt, and bacteria build up in the footbed. If you’ve ever taken a whiff of your flip-flops after a beach day, you know what we’re talking about. And if you’re wearing the same pair daily without cleaning them, the smell compounds.
How to Fix It:
- Wash your feet daily and exfoliate regularly.
- Let sandals air out after use, and avoid wearing the same pair two days in a row.
- Wipe the footbed down with a vinegar-water solution once a week to kill odor-causing bacteria.
- Try sandals with natural, breathable footbeds, such as cork or leather.
Smelly feet in sandals isn’t a hygiene failure—it’s biology. But a little care goes a long way to keeping your summer fresh.