We’ve all been there before. You take off your shoes after a long day and get hit with that noxious odor emanating from your feet. As you crinkle your nose and wonder if your feet always smelled this bad, you ask yourself – why DO feet smell so awful?
It turns out there’s quite a bit of science behind foot odor. Our feet have more sweat glands per square inch than any other part of our body, which creates prime conditions for bacteria to thrive and produce pungent smells. Understanding what causes stinky feet can help us control and prevent it.
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Sweat, Bacteria, and Smelly Chemicals – A Stinky Combination
Sweat itself is nearly odorless. It’s the bacteria on our skin that love to feast on sweat and produce smelly substances as waste. The most common culprit behind stinky feet is Brevibacterium, which lives deep within the crevices and pores of our feet.
As we go about our day, our feet sweat continuously, creating a warm, moist environment that Brevibacterium absolutely loves. The bacteria rapidly multiplies and starts digesting the sweat into acids that have strong, distinctive odors. Isovaleric acid is one main byproduct and is known for its pungent, cheesy smell that assaults our noses.
Besides sweat, dead skin cells also accumulate between toes and on the soles of our feet. Anaerobic bacteria – bacteria that thrive without oxygen – feast on these dead cells and produce even more nasty acids, intensifying the stench.
So in essence, stinky feet stem from a perfect storm – copious sweat interacting with thriving bacteria that munch on feet byproducts and release a toxic smelling gas cocktail for us to smell and recoil from.
Not Just Your Feet
While we notice odor most strongly emanating from our feet, the scientific culprit, Brevibacterium, resides all over our body. In fact, these bacteria produce that signature old-locker room smell wherever they reside. Sweat and rapid bacterial growth all over our bodies leads to generalized body odor. Our feet just happen to produce some of the worst smells due to their confinement in shoes and heaviest sweating.
Besides feet and elsewhere, Brevibacterium also flourishes inside our belly buttons and produces belly button lint. So in a way, feet, armpits, and belly buttons all share very similar science behind why they can get so stinky.
When Do Feet Start to Smell?
Most people don’t emerge from the womb with inherently smelly feet. Babies’ feet typically do not have a strong odor thanks to not producing much sweat or dead skin cells for bacteria to munch on just yet.
So when DO nasty foot smells start manifesting? In most cases, feet begin emanating more odor during puberty. This correlates with major hormonal shifts that trigger our apocrine sweat glands to become active and produce more sweat across the body, including the feet. The smelly feet phenomenon surfaces once sweat mixes with bacteria.
Besides hormonal changes, factors like hygiene, diet, weight gain, and choice of shoes also influence how soon in life feet start to smell. Genetics also play a role in determining smelly feet. Some racial demographics, such as East Asians, have lower apocrine sweat gland activity genetically and thus tend to have less issues with foot odor.
Regardless of when it starts, the vast majority of adults suffer from foot odor chronically to some degree if they do not practice proper foot hygiene.
Ways to Curb Stinky Feet
With sweat, bacteria, and dead skin buildup behind why our feet smell so awful, we actually have many options to gain control over our odor. Going after the 3 main contributing factors is key.
Reduce Sweating
Wearing breathable shoes and socks so sweat evaporates rather than gets trapped is very helpful. Often just taking off our shoes helps air things out. Using antiperspirant or wearing moisture wicking socks can further curb excess sweating that feeds smelly bacteria.
Exfoliate Dead Skin
Gently scrubbing feet in the shower, soaking feet, and occasionally applying foot masks/scrubs removes much of the accumulated dead skin cells that bacteria consume. So regularly exfoliating minimizes bacteria food source and waste production. Using a pumice stone also smooths calluses – prime bacterial breeding grounds.
Inhibit Bacteria Growth & Neutralize Odor
Washing feet daily with antibacterial soap diminishes bacteria numbers, resulting in fewer odorous bacterial byproducts. After washing, applying antibacterial creams or powders further inhibits bacterial development.
Applying foot spray at the end of the day can also tackle growth of lingering foot bacteria. Foot spray often contains compounds like cyclodextrin that encapsulates and traps odiferous molecules to neutralize nasty scents before they reach our noses.
Our Feet Keep Us Moving!
While smelly feet can be unpleasant, always remember they play an integral role in our mobility and quality of life. Maybe next time you encounter someone’s stinky feet, instead of turning away in disgust, remind yourself of the complex biological processes at work and be grateful for your feet! With some care, we can happily keep our feet fresh while we continue striding along in comfort.
