Why Your Gym Clothes Smell Absolutely Horrible

Readjusting to the new normal will be difficult, so don’t make it worse than it has to be. If you’re an avid gym-goer, make sure you follow the proper gym etiquette. And I’m begging you, please, don’t be the person whose gym clothes smell.

Sure, everyone stinks a bit when they exercise, but there is always that person — man or woman — who smells like they haven’t taken a shower in a weak. You can usually catch a whiff of their body odor all the way from the stretching area!

Still, I’m not here to smell-shame anyone, but to simply offer a bit of advice on why your gym clothes smell horrible. I’ve sniffed out the science behind body odor and investigated the best materials for odor-resistant gym clothes (Merino wool, wink, wink). I’ll also suggest a few of my favorite activewear apparel that stays fresh (for both men and women), even when you don’t.

Men Working Out
Photo by Bruno Bueno from Pexels

Disclaimer: To maintain genuineness and authenticity, Merino Wool Gear DOES NOT sponsor products. Yet as an Amazon Associate, we may earn a commission from qualifying purchases.

Sniffing Out The Truth Behind Body Odor

Alright, let’s take a step back here and figure out why you smell.

It’s a common assumption that when your foul-smelling, musty B.O. simply radiates from your body when you work out. Basically, if you sweat, you smell. 

But that’s not exactly the case. And the truth is a little more disgusting.

It’s hard to imagine, but you have millions of bacteria living on your skin. For these microorganisms to survive, they must eat. And what do they snack on? Your sweat, of course!

The proteins and other nutrients in your sweat provide fuel for the bacteria. They digest these sweat nutrients and output what we know as body odor in the form of volatile organic compounds (VOCs).

In other words,   bacteria snack on your secretions and fart out a nasty smell. Crazy, right?

That’s not all, though. These bacteria thrive and multiply in warm, moist areas of your body. Thus, the more bacteria, the worse the smell. That’s why places like your armpits, feet, and pelvic region, stink worse than the rest of your body.

Gross — I know — but it’s the truth. Okay, Okay, now here’s where it gets even more tricky.

Your gym clothes, no matter how non-odorous they may seem, still have tons of bacteria on them from your previous workout session. This is especially true if you stuff them in a wet duffel bag in your trunk. Thus, when you start to sweat again, both the bacteria on your skin and your clothes create one big mega cloud of body odor.

Just to quickly recap, bacteria eat the nutrients in your sweat. They emit a smell in the form of volatile organic compounds (VOC), and that’s why you smell.

So, Why Do Your Gym Clothes Smell?

Well, hopefully, by now, you understand that your body odor is not your body odor; it’s the bacteria. So the key is to control the bacteria, thus controlling the smell.

But, there is one missing element: why do some clothes smell after being washed?

Well, the science gets even more fascinating. Typical synthetic materials like nylon and polyester (like an Under Armour shirt) are naturally quick-drying. Thus, when those VOCs are released, they become trapped in the fabric structure itself. It’s not just the bacteria producing the smell but also the odor itself sticking to the fabric’s microstructure.

And that’s where Merino wool comes in.

Unlike synthetics, Merino wool has a high moisture absorption capacity. The hydrophilic keratin structure (the same as human hair) invited moisture to become trapped within the fibers. So much so, it can hold up to 30% of its own weight in water without feeling wet.

Therefore, when those pungent bacterial VOCs make it to the Merino fabric, they gravitate toward the moisture and not the material itself. In other words, your body odor gets trapped in the water vapor. Once that moisture evaporates, the smell leaves with it, and your clothes remain fresh.

Think about it like a toilet. If you go number two without any water in the bowl, it’s going to smell a lot worse. I know it’s a gross analogy, but it exemplifies the science pretty well.


Additional Evidence: The Dry Test

To further exemplify this point, the good people over at besthiking.net did a dry test when comparing different hiking t-shirts. They found that the synthetic blend was the quickest to dry, which is suitable for some applications. But, if you’re worried about odor, the faster it dries, the more likely it will stink.

You can learn more about this experiment in our piece The Disadvantages of Merino Wool. For now, here are a brief summary of the results.

GarmentMaterialDry Time
Woolly Ultralight Crew Neck100% Merino48 minutes
Under Armour T-Shirt100% Polyester34 minutes
Icebreaker Tech T-Lite87% Merino /13% Nylon34 minutes
Klattermusen Eir70% Merino / 30% Silk50 minutes
Data adapted from besthiking.net

Note: If you’re looking into purchasing a Merino wool t-shirt but are worried about its moisture management properties, you shouldn’t be. The fabric itself may absorb water vapor and sweat, but it doesn’t actually feel wet. AS previously mentioned, studies have shown it can hold about 30% of its own weight in water while still feeling dry to the touch.

Recommended Odor-Resistant Clothes For The Gym

Merino wool by itself is excellent for activewear, but it’s also a delicate fabric. If you workout a roughly, you should still look for clothing blended with synthetics for better fit, functionality, and longevity. Also, if you are a heavy, heavy sweater (like buckets at a time), then you may want to stick with pure synthetic clothing.

Here are a few of our favorite Merino wool outfits for the gym for both men and women.

Suggested Men’s Merino Wool Activewear

Icebreaker Tech Lite Short Sleeve Crew

When you’re at the gym, you need a shirt that moves with you. The Icebreaker Tech Lite crew is the perfect option. The ultralight, 150 GSM fabric is exceptionally breathable and offers a high level of performance. The slim, athletic fit also showcases your muscles. In other words, the Tech Lite crew works well, feels good, and makes you look good while you’re working out.


Woolly Clothing Men’s Merino Pro-Knit Warm Up Shorts

Athletic shorts aren’t usually the first thing you think of when talking about Merino wool. However, Woolly Clothing isn’t your typical Merino wool company. They create foundation wear that fits in with your daily life. Their Pro Knit Warm-Up shorts fit in perfectly with your activewear wardrobe. The light-to-midweight fabric and enhanced fabric engineering make them great for both the gym and everyday life.


Ridge Merino Men’s Ridge Boxer Briefs

With an excellent price-to-quality ratio, these boxer briefs by Ridge Merino make a great pair of workout underwear. They use a specific Merino wool and nylon blend— (m)Force™ technology— that is up to 50% stronger than pure Merino fabrics. Moreover, the 6″ inseam and tight-fitting waistband reduce unnecessary movement and bunching while you’re lifting weights. These boxers are genuinely made for comfort and performance.


Darn Tough Hiker No Show Light Cushion Sock – Men’s

You may not think that socks matter much in the workout world, but that’s where you would be wrong. Darn Tough has created a durable yet straightforward lightweight sock for any occasion (even though we like to wear them when we work out). The lightweight fabric, combined with these Merino blend socks’ enhanced breathability properties, makes them a must-have for those who suffer from foot odor. Suppose you are looking for a different style, ankle height, or cushion level. In that case, you can check our full Darn Tough socks review and company profile.


Allbirds Men’s Wool Runners

The simplistic, classic look of the Allbird’s runners will keep your feet smelling fresh, even when you sweat. The Merino wool knit construction — crafted from ethically sourced ZQ Merino — is breathable and uber comfortable. The flexibility of this sneaker allows for a broader range of movement. Thus, you don’t have to worry about irritation and rubbing while working out. Above all, we love the versatility of these sneakers. And since they won’t stink after you exercise, you can wear them all day long!

Suggested Women’s Merino Wool Activewear

Minus33 Merino Wool Lafayette Women’s Lightweight Tank Top

This Minus33 Merino tank top may look basic initially, but it’s full of high-performance features. The overall fit is engineered to hug your curves without being restrictive. Luxurious, 17.5-micron Merino wool material provides a fantastic next-to-skin feel. Moreover, the 170 GSM ultralight fabric is breathable but isn’t thin enough to snag on any gym equipment. If you don’t like the charcoal gray color, Minus33 also has four other colors available. Check one out today!


Icebreaker Merino Sprite Racerback Sport Bra

When you think about sports bras, Merino wool isn’t usually the first fabric that comes to mind. But, since you need enhanced breathability to combat boob sweat, it’s probably your best choice. And one of our favorite Merino wool sports bras is the Icebreaker Sprite Racerback. The stretchy, moisture-wicking material is not too tight but still offers plenty of support. With 20+ color options and an awesome Icebreaker guarantee, it’s basically the goldilocks of sports bras: it’s just right.


Meriwool Merino Wool Base Layer Leggings

If you’ve noticed so far, much of these recommended Merino wool Activewear clothes are expensive. Yet, a few companies out there have produced quality wool clothing at a relatively affordable price. One of these brands is Meriwool, and their midweight Merino leggings are a solid activewear choice. The ultrasoft, 18.5-micron fibers make them one of the most comfortable pair of leggings on the market. We think they’re perfect for the treadmill, yoga class, and even just lounging around the house.


Darn Tough Vertex No Show Tab Ultra-Light Cushion Sock

You can’t get much more ultralight in the sock department than Darn Tough’s Vertex socks. The no-show style sock is known for an exceptional foot feel as the ultralight yet durable fabric gives you better contact with your shoe. This is necessary for explosive, plyometric exercises like box jumps, giving you much better control. Moreover, these Vertex socks are breathable and even have targeted mesh zones on top of the foot that promote airflow. Your feet will feel great after your workout, and your socks won’t smell afterward!


Merinos Women’s Lace Up Shoes

Throw out all your gym shoes — seriously. They stink, and you’ve most likely gone nose blind to the smell. Instead, trade them out for a pair of Merinos Shoes. The simplistic, comfortable, and versatile design makes them great for the gym, the store, or even work! The soft Merino exterior is highly breathable and odor-resistant. Moreover, these lace-ups come in 20+ colors and designs, so you may just want to snag a couple of pairs!

Note: If you have wide feet, you’re in luck. Merinos offers many wide sizes within their collection. They aren’t available for every color, but you can always contact them to learn about availability.

Final Note About Why Your Gym Clothes Smell

To sum up, the millions of bacteria on your skin and clothes eat the nutrients in your sweat and excrete what we know as body odor. To control this odor, you should first keep yourself clean and then make sure your clothes stay fresh by wearing Merino wool.

Even though Merino wool is odor-proof, that doesn’t mean that you are. No amount of clothing will make you not stink at the gym if you aren’t already clean. So, make sure to take a quick rinse in the shower before (and after) hitting the gym to stay fresh all day.

For more information about the science behind Merino wool, gear reviews, and great general information, follow us @merinowoolgear on Instagram.

If you have any questions, concerns, or corrections, feel free to contact us via email, as well.

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