We’ve all experienced it – that unpleasant, pungent odor emanating from sweaty shoes and sneakers after a long day. While airing them out may help briefly, the smell inevitably returns. So what causes the stench, and how can baking soda help?
The source of shoe odor lies in the bacteria, fungi, and microorganisms that thrive in the warm, damp environment inside the shoes as we wear them. Our feet contain over 250,000 sweat glands that release moisture and salt, providing an ideal breeding ground for these microbes. They feed on dead skin cells and the sweat that we produce, releasing unpleasant waste products and gases like isovaleric acid as a byproduct of their metabolic processes. This is what produces the noxious stench.
Certain types of bacteria, namely Bacillus and Staphylococcus, are more prevalent in generating foot and shoe odors. Fungal infections between the toes, such as athlete’s foot, can also contribute to a stronger smell. The bacteria multiply rapidly in shoes when we wear them sockless or reuse them frequently without washing. Even moisture from weather and perspiration on the outside of shoes can enable odor-causing bacteria to grow.
Baking soda, also known as sodium bicarbonate, is effective at reducing shoe odors because of its ability to neutralize acids and absorb moisture. When baking soda comes into contact with sweaty shoes, a simple chemical reaction occurs. The sodium bicarbonate reacts with acidic odor molecules produced by bacteria, neutralizing their acidic properties. Acetic acid, isovaleric acid, and propionic acid are examples of smelly acids produced in shoes that baking soda can deactivate.
This neutralization stops the pungent acids from smelling and inhibits their proliferation. Baking soda also has antimicrobial properties that prevent bacteria and fungi growth when it is sprinkled on shoes. It creates an environment less suitable for their survival.
In addition, baking soda absorbs excess moisture inside shoes that allow microbes to thrive. It draws in and traps the sweat and perspiration in the shoes, keeping them dryer. The reduced moisture curtails microbial growth and associated odors. Baking soda has an impressive water holding capacity – it can absorb over twice its volume in liquid. A study published in the International Journal of Cosmetic Science found baking soda solutions reduced foot odor by 70% compared to untreated feet.
To leverage baking soda for smell reduction in shoes, first remove shoe inserts and loosen any debris inside with a washcloth. Shake a generous amount of baking soda directly into the shoes, about 2-3 tablespoons per shoe. Massage the powder in well so it reaches deep into the fabric, getting underneath the insoles and into crevices where odors congregate. Let the baking soda sit overnight or up to 24-48 hours to fully absorb odors and moisture.
You can sprinkle extra baking soda directly on feet or socks as well, before putting shoes on. This creates a hostile environment for microbes from the get-go. After 1-2 days, dump out the used baking soda from shoes. Using a brush, vacuum out any remaining residue. Allow shoes to air dry if any moisture is still present before using again. Freshen shoes regularly by repeating the baking soda treatment each week, or whenever odors return.
While baking soda is not a disinfectant, it provides an easy, non-toxic way to soak up the stinky byproducts of bacteria and fungi living inside shoes. The abrasiveness of the powder also helps remove dead skin cells and debris that contribute to the foul smell. Its neutralizing and absorbing capabilities keep odors at bay without harsh chemicals.
Along with sock hygiene and regular laundering of shoes, baking soda can keep your feet and footwear smelling clean. A simple household staple, baking soda offers an inexpensive, natural solution for clearing the air and creating more pleasant aromas in sweaty shoes. Just a sprinkle keeps them dry and odor-free, so you can walk confidently without worrying about stale smells giving you away.