Why Do My Running Shorts Smell So Bad? (6 Proven Cleaning Methods)

Running stinks! There’s no doubt that the positive impacts of becoming a runner include increased cardio-vascular fitness and toned muscles. The negatives, however… laundry, laundry, and more laundry. What’s especially brutal about runners’ laundry is the putrid smells it can produce! If you find yourself wondering, “Why do my running shorts smell so bad?” You’ve come to the right place. 

Sweaty running shorts invite all kinds of bacteria, especially when left in the hamper. Sweat and body oils can get trapped in synthetic fabrics meaning the odor can remain even after being washed. While sometimes the solution may be as simple as running a cleaning cycle on your washer, you may need to soak your running shorts to get the odor out.

Keep reading for a full explanation of why your running shorts stink and six proven cleaning methods to make sure you’re hitting the pavement fresh.

Why your running shorts smell so bad even after washing

There’s nothing more frustrating than pulling a pair of running shorts out of the dryer and realizing you’ve baked a raunchy odor into the very fabric of the shorts. Sometimes, no matter how many times you wash, certain types of apparel just don’t seem to be able to shake their stench. 

So why do your running shorts smell bad even after washing?

The main causes of persistent odors in your running shorts are the bacteria and body oils that absorb into the fabric over time. As you sweat, the synthetic fabric that most newer pairs of running shorts are made of absorbs oils that are secreted from your body. These can be difficult to remove from the shorts even with traditional wash detergents. 

The synthetic fabrics used for most running shorts absorb the sweat and oils from your workout.

The accumulation of body oils, sweat, dirt, skin cells, and other bodily secretions is called sebum. This sticky solution can be difficult to remove from the fabrics of most athletic clothing. 

This pernicious problem can be extremely frustrating to deal with. Especially considering the costs of modern running shorts. Nobody wants to throw away a brand-new pair of perfectly good shorts because of an unpleasant stench.

Never fear! I’ve gathered the top six best ways to get that stink out of your running shorts.

Synthetic fabrics

Most modern running shorts are made from synthetic fabrics because they can be developed with properties lacking in natural fabrics of fibers.

Synthetic moisture-wicking technology is great for all manner of athletes to aid in cool-down and reduce chafing. However, the increased absorption rate means that these fabrics also absorb more oils than other fabrics.

Once your synthetic shorts absorb too much oil, not only will they stink, but they’ll also be less effective at moisture-wicking. It’s probably a good idea to schedule a regular deep clean of your heavily used running shorts before a major issue develops.

Natural fabrics like cotton

While synthetic fibers attract body oils that trap bacteria that cause bad smells, cotton absorbs moisture but doesn’t appear to be a breeding ground for the bacteria that cause bad smells.

Natural materials like cotton are more resistant to accumulating bad odors over time. If you’re having particular difficulties with smelly running shorts, consider switching to cotton.

Using warm water, a quick wash of your cotton shorts should kill the pungent bacteria that clings to synthetic running shorts. 

While one oft-cited study indicates that clothing made from bacteria has antibacterial properties, this has never been proven. However, bamboo viscose has been shown to slow bacterial growth.

Washing machine

Sometimes the problem may not lie in your shorts.

You might have your washing machine itself to blame for your bad-smelling clothes. Various types of washing machines are more susceptible than others to succumbing to bad odors.

Sometimes the source of your running shorts' bad smell is the washer itself.

While front-loader machines are superior to their counterparts, all types of washing machines can become smelly because of the following process. 

The use of low-efficiency detergents (detergents that don’t fully wash out during the rinse cycle) can lead to the development of a layer of soap scum around the rim of the machine. Over time, this layer of scum can trap dirt, oils, and other bacteria from your dirty clothes. The warm, moist environment inside the machine is a perfect breeding ground for more bacteria and mildew, which can lead to a smelly washer. 

This will obviously impact the way your clothes smell. Keeping a clean washing machine is vital for avoiding musty shorts.

If you find yourself dealing with this problem, take the following steps to properly deodorize your machine, so you can keep your clothes smelling fresh and clean:

  1. Mix ¼ cup of baking soda with ¼ cup of water and pour it into the machine’s detergent container.
  2. Pour 4 cups of white vinegar into the drum of your top-load machine or 2 cups for a front-load model.
  3. Run a cycle on the highest temperature.

After following these steps, your machine should be clean and ready to use!

How to clean stinky running shorts – 6 Methods

There are a number of proven cleaning methods that may remove odors from your smelly running shorts.

The best ways to clean your smelly running shorts are:

  1. Wash inside out
  2. Wash alone or with like fabrics
  3. Use less detergent
  4. Pre-soak in white vinegar & baking soda
  5. Use sport detergent
  6. Buttermilk soak

Take a look at these tips and incorporate each method into your routine for the most effective cleaning. The list is arranged with the least difficult and cheapest methods first, with the more involved and more expensive methods last. 

Wash inside out

The simplest, cheapest, and generally most straightforward way to try to get the smell out of your running shorts is to turn them inside out before washing them.

The cause of the odors and smells originate from contact with the inside of your shorts, not the outside. Make sure to turn your clothes inside out to eliminate the smelliest odors in the wash.

Basically, this gives the washer and detergent more opportunity to remove the oils and any bacteria from your shorts.

Supplies needed

This one is fairly straightforward. 

Washing your smelly shorts inside out requires the same supplies as simply washing them normally:

  • Washing machine
  • Laundry detergent

Turn shorts inside out

Turn your shorts inside out before placing them in the wash. 

Wash

Run the wash cycle as normal.

Wash alone or with like fabrics

When you wash with other, heavier fabrics, it can be difficult for the detergent to get through to the clothes you’re trying to deodorize.

Washing your smelly running shorts alone or with like fabrics can isolate the putrid culprit from other items.

If you’re having an issue with stinky running shorts, try doing a load of laundry specifically for activewear. 

Supplies needed

Similar to the previous cleaning method, the supplies needed here are very simple.

To wash the bad smell out of your running shorts by laundering them with other activewear, you’ll need:

  • Washing machine
  • Laundry detergent
  • A load of activewear

Load washer with activewear

Load your machine with your stinky running shorts and other forms of athletic apparel. 

Add detergent

Pour in your detergent.

Wash

Run a normal cycle.

Consult the care tags for your clothing for the washer settings. Most activewear should be washed in cold water on the gentle cycle in order to extend its lifespan.

Use less detergent

Washing with too much detergent can lead to the build-up of soap scum on your clothes and on the inside of the drum which can trap odors and provide ground for bacteria to thrive.

Ensuring you use only the recommended amount of laundry detergent when washing your clothing will help reduce build-up on both your clothing and the inside of the washer itself. This means that the shorts will be less likely to retain odor and the washer will be able to better fulfill its function.

Depending on your washing machine type, you may also want to check that you’re using the appropriate detergent. For example, if you have a High Efficiency (HE) machine, you’ll need to use an HE detergent.

Supplies needed

In this case, you’ll likely be using the same supplies as you do during your regular laundry routine.

To wash your running shorts to reduce the lingering bad smell, you’ll need:

  • Washing machine
  • Laundry detergent

Of course, if it turns out you’ve been using a laundry soap that isn’t appropriate for your machine, you’ll want to purchase the correct detergent.

Load the washer

Load your machine with your stinky running shorts.

Add detergent

Add the recommended amount of the appropriate laundry detergent – or even slightly less.

Wash

Wash the load as normal.

Pre-soak in white vinegar & baking soda

The pre-soak method involves soaking your shorts in cold water with white vinegar and baking soda before washing. 

Pre-soaking your smelly shorts can remove the odor as baking soda neutralizes the pH in the acids that produce bad smells in your clothing. White vinegar focuses on stain removal, as it is excellent at removing grease and oils, which may also cause some odors. 

Pre-soaking smelly running shorts in a vinegar and baking soda solution is a great way to remove both bad smells and stains.

As long as you wash your shorts properly after soaking, you don’t need to worry about replacing that old sweat stink with a vinegar smell.

Supplies needed

Chances are you already have everything you need to pre-soak your smelly shorts, although you may never have considered using them for your laundry.

To pre-soak your stinky shorts, you’ll need:

  • White vinegar
  • Baking soda
  • One-gallon tub (or large sink)
  • Cold water
  • Washing machine
  • Laundry detergent

Prepare the tub

Fill a one-gallon tub with cold water.

If you don’t have a standalone tub, fill a clean sink with cold water.

Make the pre-soak solution

Add 1 cup of white vinegar and 1 cup of baking soda to the water.

Pre-soak shorts

Submerge your smelly shorts for at least 30 minutes. 

Wash

Throw your pre-soaked clothes into a normal wash cycle. 

Use sport detergent

Some detergents are made for hardier jobs.

Sport detergents or laundry boosters can eliminate odors in otherwise hopeless laundry conundrums. If your running shorts are proving to provide a persistent pungency, try this method. 

While there are lots of sports-oriented detergents available, I personally use this one from Rockin’ Green.

Supplies needed

If the previous steps haven’t had an effect on the unpleasant odor emanating from your running shorts, you may need to purchase a detergent developed specifically to remove tough stains and odors.

For this method, you’ll need:

  • Washing machine
  • Sport detergent
  • Sport pre-soak (optional)

Prepare the tub

Fill a one-gallon tub with cold water.

If you don’t have a standalone tub, fill a clean sink with cold water.

Make the pre-soak solution

Depending on the sport laundry detergent you have, you may be able to use the same detergent as the pre-soak or it may be offered as a separate purchase.

Make the pre-soak based on the manufacturer’s directions.

Wash

Wash the pre-soaked shorts using the sport detergent based on the manufacturer’s directions.

Buttermilk soak

Similar to the white vinegar and baking soda method, the buttermilk soak method involves soaking your mildewy running shorts in buttermilk before placing them in the wash.

An overnight soak using this method can remove the odor from clothes that have been trapped at the bottom of your gym bag, or the laundry hamper for long periods of time. Do this the night before washing for the best results. 

This method is for particularly pervasive smells.

Supplies needed

If you’re anything like me, you probably don’t have at least a gallon of spare buttermilk in the fridge, but it might be worth picking some up if the alternative is needing to replace your pricey running shorts.

To use a buttermilk soak to remove the stink from your running shorts, you’ll need:

  • Buttermilk
  • One-gallon tub (or large sink)
  • Laundry detergent

The amount of buttermilk you’ll need depends entirely on how many pairs of smelly shorts you’ll be soaking.

Fill tub with buttermilk

Fill a large tub with buttermilk (enough to cover your stinky clothes and shorts).

Pre-soak shorts

Add smelly running shorts (and other sweaty athletic gear) to the buttermilk soak. Ensure that the clothing is completely submerged.

Allow to soak overnight.

Rinse

Remove clothes from the buttermilk soak and rinse with cold water.

Wash

Place clothes in the wash and run a normal cycle.

How to prevent running shorts from smelling so bad

So you’ve learned how to eliminate odors in your smelly running shorts, but how do you go about preventing this phenomenon in the first place?

To keep your running shorts from starting to smell to begin with, you should:

  • Wash directly after use
  • Put them in the freezer
  • Avoid fabric softeners
  • Air dry before washing
  • Air dry after washing

Implement these techniques to avoid having to deal with the hassle of the cleaning methods mentioned above. 

Wash directly after use

Make sure not to leave your running shorts to sour in the hamper.

To avoid giving your running shorts the opportunity to start to smell, wash them immediately after running. If you leave your sweaty, wet running shorts in the hamper for long periods, they will develop bacteria and mildew that will produce disgusting odors over time.

If you don’t like science experiments, make sure to wash your running shorts directly after use!

Put them in the freezer

This may seem extreme, but freezing your shorts can eliminate odors before they become a foothold on your clothing.

After a run, if you don’t have time to wash, rather than throwing your running shorts in the laundry hamper, put them in a large resealable baggie and place them in the freezer.

The extremely cold temperatures will neutralize the growth of odorous bacteria, making it possible for you to wash them later and avoid bad smells. 

Avoid fabric softeners

Fabric softeners can actually produce bad odors in clothes, as they tend to congeal and leave a film on your clothing that traps in odors.

If you want to prevent your running shorts from smelling bad post-wash, try washing them without fabric softeners. 

Air dry before washing

Hanging your wet running shorts up to air dry after a run can prevent bad odors from forming at the bottom of a laundry hamper.

Additionally, the sun can evaporate some of the sweat and body oils that cause bad smells in the first place. If you have time, go ahead and air your shorts out before deciding to wash them. 

Air dry after washing

Air drying your shorts after a wash can also prevent odors from staying around in your running shorts.

Machine drying can often produce extreme temperatures that end up baking smells into your clothes. Letting them dry in fresh air is a much safer way of preventing bad smells in your running shorts and apparel.