How to Deal with Smelly Gym Shoes – Advice From the Experts

In this article, we discuss how to keep gym shoes from smelling and how to get the smell out of gym shoes, providing you with plenty of top tips to help you keep your footwear fresh. We also examine the science behind bad odors in shoes and teach you about the surprising source of unpleasant smells.

What causes bad smells in gym shoes?

The first thing to understand about smelly gym shoes is that sweat is not directly responsible for producing odors. To locate the source, you need to whip out your microscope and get sciency. Because bacteria are the real problem.

Bacteria are single-celled organisms that are present in almost every environment on Earth. They play a critical role in the nutrient cycle and are responsible for breaking down materials to create new compounds. Which, as we’ll learn, can be a problem.

Microorganisms like bacteria and fungi thrive in warm, dark, and moist conditions. Like shoes. When you sweat into your shoes, the bacteria break down that sweat into various byproducts that cause bad odors. Before we go deeper into the science, let’s examine the conditions that promote bacterial growth.

• Moisture – Microorganisms love moisture. And the sweat inside your shoes provides plenty of moisture, ensuring the bacteria benefit from an ideal breeding ground.

• Lack of ventilation – Poor airflow prevents moisture from evaporating. This traps the moisture inside the shoe and creates an environment that promotes bacterial growth.  

• Wearing shoes every day – If you wear your gym shoes every day, they may not get a chance to dry out. As we have already established, moist shoes mean more odor-causing bacteria.

• Poor quality socks – Wearing socks made from non-breathable materials can result in more sweat and more moisture. Similarly, wearing socks several days in a row allows bacteria to multiply and transfer to your shoes.

The science behind gym shoe odors

Having examined the conditions that enable bacteria to multiply, it is time to turn to the biological processes that result in bad odors. In other words, why and how do bacteria cause smelly gym shoes?

• Metabolic processes – Certain bacteria consume organic compounds to generate energy. This is known as a metabolic process. Having consumed these compounds, bacteria grow and multiply, spreading across materials. Sweat typically contains various proteins and salts that bacteria can metabolize, allowing them to prosper. 

• Breaking down compounds – Bacteria use enzymes to break down the organic compounds in sweat. These reactions turn complex compounds into simpler ones, creating a host of byproducts in the process.

• Volatile compounds – Some of these byproducts really smell. Usually, they are known as volatile organic compounds (VOCs). These compounds evaporate easily, resulting in airborne odors that can be very unpleasant.

• Sulfur-based compounds – This is another type of byproduct responsible for bad odors. As the name suggests, they contain sulfur, which can reek a little. Some bacteria break down sulfur-containing amino acids in sweat to produce hydrogen sulfide and methanethiol, both of which stink out the place.

Understanding how bacteria cause unpleasant odors can help us take preventative and remedial measures that ensure our shoes smell better. It also explains why it is essential to address contributing factors, such as moisture and ventilation.

What part of the shoe is most responsible for bad smells?

Generally, the insoles and the footbed are the worst offenders. This is largely because they are the part of the shoe with the most consistent contact with the foot and generates the most sweat. Insoles are not always made out of particularly breathable materials, either. A lack of breathability means more sweat and less evaporation. 

Sometimes, other parts of the shoe contribute to bad-smelling footwear. For instance, the toebox can cause issues. However, the uppers on a gym shoe are usually breathable and, as a result, much less likely to be the source of unpleasant odors. Still, check every part of the shoe to ensure that it is the insole or footbed causing most of the problems.

Remedial or preventative action?

When it comes to tackling the issue of smelly gym shoes, you have two options. You can implement preventative measures that aim to stop problems from developing in the first place. Or you can take steps to eradicate smells once they develop.

In our opinion, it is best to try both. Preventative action will limit the extent of the bad odors your shoes generate. Remedial action will eliminate anything that remains. 

How to keep gym shoes from smelling

Your anti-odor journey begins with preventative measures that should stop foul odors in their tracks before they become a serious problem. These measures include:

• Rotating your shoes

If you have two pairs of gym shoes, try rotating between them, using one pair the first day and another the next. It will give your shoes time to air out and for the moisture to evaporate, preventing bacterial growth and bad odors.

• Air your shoes out

After wearing your shoes, remove the insoles and place them in a well-ventilated area to air out. If possible, avoid storing your footwear in spaces with poor ventilation, as this will inhibit evaporation and allow moisture to build up, creating ideal conditions for bacteria.

• Opt for breathable shoes

Gym shoes made from breathable materials enable the air to circulate more effectively. In turn, this helps moisture to evaporate, eliminating the main contributing factor to bacterial growth. Many modern gym shoes now use breathable materials for performance reasons, so finding a pair shouldn’t be too difficult.

• Try moisture-wicking socks

Preventing smelly gym shoes isn’t all about the footwear. Socks play a big part too. Moisture-wicking socks designed for use in athletics and other sporting activities take sweat away from the feet and footwear and allow it to evaporate. This can significantly affect the amount of moisture your shoes retain, creating an environment that is less amenable to bacterial growth.

• Clean your feet regularly 

As well as wearing appropriate socks, it pays to take good care of your feet. Wash and dry them thoroughly whenever you shower and even before putting on your shoes. If you struggle with smelly feet, foot powders, and antifungal sprays can help eliminate odors and ensure they don’t transfer to your shoes.

• Use special insoles

If your shoes come with standard insoles, you may want to replace them with new insoles that prevent the build-up of moisture and bacteria. This could mean purchasing moisture-wicking insoles or insoles treated with an antimicrobial solution, such as Polygiene StayFresh™.   

• Look out for Polygiene-treated products

Polygiene-treated athletic products utilize advanced antimicrobial solutions like Polygiene StayFresh™ and Polygiene OdorCrunch™ to eliminate smells at the source. They employ anti-odor technologies, including silver ion and silica-based approaches, to prevent the growth of bacteria and break down odor-causing compounds. You can find them in a variety of popular sports and footwear products, including Dr. Scholl’s insoles, The North Face socks, and GripGrab cycling apparel.

How to get the smell out of gym shoes

To remove smells from footwear, we recommend taking the following actions.       

• Odor-absorbers and absorbent technologies

Keep odor absorbers in your shoes to soak up the excess moisture. Less moisture means fewer bacteria, helping to neutralize any bad odors emanating from your footwear.

• Baking soda in your shoes

Baking soda is excellent at absorbing moisture and helping to tackle the conditions responsible for bacterial growth. Sprinkle a little in and leave it there overnight. You will have to shake out the powder the next time you wear your shoes, so it’s not always the most practical solution. But it can be a good short-term fix.

• Use charcoal

Activated charcoal is another good odor-absorber in shoes. It usually comes in the form of inserts or sachets, and you can leave it in your shoes to absorb moisture and bad smells. 

• Put your shoes in the freezer

Bacteria do not like sub-zero temperatures. It is why we keep food in the freezer when we want to preserve it. You can seal your shoes in a plastic bag and put them in the freezer overnight. It should kill all bacteria present. But you will need to thaw them out before you wear them again.

• Expose your shoes to sunlight

The UV rays from the sun can help kill odor-causing bacteria, so leaving them out in the sunshine is a good idea. It may not be the most effective method, but you can combine it with other actions to reduce odors.

• Shoe sprays

Anti-odor shoe sprays are available to freshen up your footwear and keep them odor-free. Just spray a little in your shoes after wearing them and let the antimicrobial active ingredients get to work. However, it is helpful to note that post-manufacture treatments are not as effective as treatments integrated into the textiles themselves, as is the case with Polygiene solutions.

• Wash your shoes

It may sound simple, but washing your shoes is an effective way to eradicate bacteria. Just make sure that your shoes are washable and read the manufacturer’s instructions. You may also need to remove the insoles before doing so.

• Utilize essential oils

Some readily available essential oils have antimicrobial properties that prevent the growth of bacteria and leave the shoes with a pleasant smell. These include tea tree and lavender oil, among others. Place a few drops on some cotton wool and leave it in your shoes.

• A vinegar wash

Vinegar does an excellent job of fighting bacteria and bad odors. It is also pretty easy to apply a vinegar wash to our shoes. Mix equal parts vinegar and water in a spray bottle, apply to your shoes, and let them dry. We recommend giving the shoes a good clean before you do so for best results.

• Citrus peels in shoes

Lemon and lime peels benefit from naturally occurring antimicrobial properties and will work to prevent bacterial growth. This means you can peel the skin from these fruits and leave them in your shoes overnight. While they are effective at eliminating microbes, they also impart a wonderfully fresh and fruity smell, leaving your shoes smelling wonderful.

• Make tea bag smell removers

The tannins in black tea can kill bacteria and prevent them from causing the foul odors you get in smelly gym shoes. However, this does require some preparation. First, boil the tea bags in water for around five minutes. Once they are a little cooler, squeeze out the excess moisture as best as you can and place them in your shoes. Leave them for 24 hours for best results. If you can only manage overnight, that should be fine. 

Polygiene technology helps prevent odors

While the preventative and remedial actions we discussed in this article will help with your smelly gym shoes issue, nothing is quite as effective as Polygiene antimicrobial solutions. Specifically developed to tackle the source of bad odors, rather than just mask smells, Polygiene solutions utilize a range of innovative antimicrobial technologies that have been tried, tested, and refined to ensure they consistently deliver results.

Check out our Polygiene StayFresh and Polygiene OdorCrunch technology pages to learn more about our groundbreaking solutions. Containing all you need to know about how these solutions work and what products you can find them in, our product pages are an excellent way to discover the power of Polygiene technology.

If you have any questions concerning Polygiene technology, please feel free to reach out to our experienced customer contact teams.