Buying used shoes is generally safe for adults if you take a few precautions, but it does carry real risks worth understanding. The two main concerns are infections from fungal or bacterial organisms that thrive inside worn footwear, and structural wear patterns that can affect how the shoe supports your foot. For children, the risks are more serious and most podiatrists advise against it.
Why Used Shoes Harbor Infections
The inside of a shoe is one of the most hospitable environments for fungi and bacteria: dark, warm, and damp. The average foot produces up to a cup of sweat per day, and much of that moisture gets absorbed into insoles, linings, and stitching. Fungal infections like athlete’s foot spread through minor cuts, skin fissures, or under the nail beds, and the organisms responsible can survive in footwear long after the previous owner stopped wearing them.
This doesn’t mean every pair of used shoes is crawling with pathogens, but it’s a real enough risk that you should always sanitize secondhand footwear before wearing it. Shoes that look visibly worn on the inside, have a strong odor, or feel damp are higher risk. Leather-lined dress shoes or boots tend to dry out more thoroughly than synthetic athletic shoes, which trap moisture in foam padding.
How Worn Soles Affect Your Feet
Every person’s gait wears down shoes in a unique pattern. Someone who overpronates (rolls their foot inward) will compress the inner edge of the midsole and grind down the inner heel. Someone who underpronates will do the opposite. When you step into a shoe that’s already been molded to a different foot’s mechanics, the uneven cushioning and tilted sole can push your foot into movement patterns it wouldn’t naturally follow.
For a lightly worn pair of leather loafers, this effect is minimal. For running shoes or hiking boots with hundreds of miles on them, it can be significant. The midsole foam in athletic shoes compresses permanently over time, so even if the outsole looks fine, the cushioning may be uneven in ways that stress your joints differently than your body expects. If you’re buying used athletic shoes, look for pairs with even sole wear and midsoles that still spring back when you press a thumb into them.
Used Shoes and Children’s Feet
This is where the advice shifts from “be cautious” to “avoid it.” Children’s bones are still forming, and their growth plates are actively developing. When a child wears shoes that have been molded to another child’s foot, their still-soft bones can follow that formation instead of developing naturally. Podiatrists have documented early bunions in children wearing shoes that were too short for them and hammertoe deformities from toes getting scrunched up in shoes fitted to a different foot’s shape.
The combination of malleable bones and someone else’s wear pattern makes hand-me-down shoes particularly problematic for toddlers and young children. Kids also tend to be less vocal about discomfort, so a poorly fitting used shoe can cause problems for weeks before a parent notices. For adults whose bones are fully formed and whose foot structure is stable, the biomechanical risk is much lower.
How to Sanitize Used Shoes
If you’ve found a pair in good structural condition, proper cleaning eliminates most of the infection risk. Here’s a practical approach:
- Remove the insoles and spray the entire interior of the shoe with a disinfectant spray. Coat the toe area, heel, and sides thoroughly enough that the surfaces are visibly wet. Spray both sides of the insoles separately.
- Let the disinfectant sit for at least 10 minutes on fabric and foam surfaces to kill fungal spores effectively.
- Dry completely before wearing. Stuffing shoes with newspaper and placing them in a well-ventilated area speeds this up. Wearing shoes that are still damp defeats the purpose of disinfecting.
- Replace the insoles if possible. Aftermarket insoles are inexpensive and eliminate the most contaminated layer of the shoe entirely. This is the single most effective step you can take.
For concerns about bed bugs, which can hide in seams and crevices, heat is the most reliable treatment. Exposing shoes to temperatures of 120 to 125°F for 20 to 30 minutes kills all life stages, including eggs. A clothes dryer on high heat works for fabric shoes. For leather or structured shoes that can’t go in a dryer, sealing them in a black plastic bag and leaving them in direct sun on a hot day can reach these temperatures, though it’s less reliable. Alternatively, freezing shoes below 0°F for at least four days kills bed bugs as well.
What to Look for Before You Buy
Not all used shoes carry the same level of risk. A barely worn pair of leather boots from a consignment shop is a very different proposition from heavily used running shoes at a garage sale. When evaluating a pair, check these things:
- Sole wear: Look at the bottom. If one side is noticeably more worn than the other, the shoe has been shaped by someone else’s gait and will push your foot in that direction.
- Midsole compression: Press into the cushioning along the footbed. If it feels flat or doesn’t bounce back, the support is gone.
- Interior condition: A shoe that’s stained, odorous, or has a worn-through lining has absorbed a lot of sweat and is harder to fully sanitize.
- Material: Leather, canvas, and rubber clean more effectively than synthetic mesh and memory foam, which trap moisture deep in their structure.
Dress shoes, boots, and casual shoes in good condition are the safest categories to buy used. Athletic shoes, slippers, and anything with heavy foam padding carry more risk, both for hygiene and for structural integrity. If you can see a clear foot impression pressed into the insole, the shoe has been significantly shaped by its previous owner, and replacing that insole before wearing is especially important.