What’s in a (Running) Sock?

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The humble running sock is underrated. A well-designed pouch within running shorts is every bit as crucial as moisture-wicking fabric in a t-shirt and headphones, without which, you’re DOA. But it doesn’t matter what’s on your body — the wrong sock will result in blisters, sores, and a swiftly ruined workout. 

Running socks are made specifically for logging miles without abrasion and excessive sweat. Everything from the materials used to the needle count and design of the cushioning and mesh is carefully considered for optimal performance. This makes these socks far superior to any ten-pack one can pick up at Costco. It also makes them more expensive. 

“Our most basic running socks have three or four colors in them, a spandex blade of yarn, elastic yarn, heel-toe spandex, a nylon, and a poly-cotton blend as well. So there are five yarns in one sock and in different places in the heels and toes. It’s complex,” said Joe Jorgensen, Vice President of Product at Stance Socks. 

SPY’s Wellness Editor, Taylor Galla, is a marathon runner and a huge believer in investing in running socks. They’re pricey, but they’ll save the owner plenty of pain and emotional distress, and they’ll help them avoid the worst after running 10, 15, and even 26.2 miles straight. 

There’s much more than meets the eye for running socks, so SPY consulted with technical experts in the field to find out what distinguishes the $30 pair from a $2 drugstore find, and why buying dedicated running socks is the pro move everyone should make. 

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What Are Running Socks Made Of?

Running socks from the two most popular brands, Stance and Bombas, and most of the options on Amazon, are made of similar combinations of the same materials. These include fabrics like cotton and synthetic options like nylon and polypropylene. 

“Most of what you’ll see out in the world is some sort of a synthetic blend. Performance socks tend to be nylon-rich. A sock can’t be 100% any one fiber. There has to be a measure of elastic and spandex in it to give it its stretch and its compression,” said Jorgensen. 

Cotton gives socks their cushion and comfort, while synthetic fabrics like nylon are durable and better suited for miles of movement. 

“Nylon as a material is intrinsically lightweight. It’s super strong, durable, and it’s also abrasion-resistant which makes nylon socks one of the most blister-resistant products on the market,” said Jorgensen. “It’s shrink-resistant, it holds fit well, and it has low moisture absorbency, so typically it has a quick dry feature to it, as opposed to poly which takes longer to dry, and cotton even longer than that.” 

He explained that from a material standpoint, it’s hard to beat a high-quality nylon for high performance. However, all socks need a balance between fabrics because no one material checks all the boxes for high performance. 

According to Ian Velardi, the vice president of product design at Bombas Socks, socks that contain too much nylon can be slippery. 

“It’s slicker than cotton yarn. So with our initial designs, we had an issue where we really liked how the sock fit but it was moving too much within the shoe. It was slipping around which is not good.” 

The way in which the materials are knitted together also matters a lot for durability’s sake. 

“Typically, you never want to link a nylon to a nylon or a cotton to cotton or a poly to a poly. You have to alternate the yarn materials so they link together nicely and they stay durable,” said Jorgensen. 

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The materials in a running sock inform the fit, user experience, and how long the sock can keep up with the user before causing a hot spot or other undesirable result. 

“When you think about a foot, an ankle, and a leg there are really weird shapes. You know? As opposed to a torso or some legs or something. Like pants are easier,” said Jorgensen. 

Jorgensen noted that making socks right and left-specific, while somewhat tedious from a user experience perspective, is crucial to designing a sock that fits well. Cheaper socks are designed with a simple half-moon for the toes, whereas Stance’s toe boxes are designed to fit the toes closer. 

“The inner sock, where it closes around your toes, is taller where your big toe is and tapers off to mimic the shape of your foot,” said Jorgensen. “That helps it fit inside your shoe better because that’s how shoes are shaped too. It reduces abrasion and fabric bunching up with material near your toes.” 

Velardi also emphasized the importance of strategic “zone cushioning” that provides more support and security to the parts of the foot that bear the brunt of the load during a run. Cushioning is controversial, and subjective according to both experts, but there are places on the foot where it’s needed. 

“There’s a little more padding in the heel and toe which are the more stressed areas when you’re moving. You don’t necessarily want that in every position because in some places you want the foot to be closer to the shoe,” said Velardi. 

Jorgensen said they also have more cushioning underneath the ball mound and the big toe of the foot for the same purpose. 

“We’ve found that people want more cushioning on the back of your ankle, underneath the heels and the toes,” said Jorgensen. 

“As you’re running, you run in a straight line, but more and more people are trail running in different terrain, and you use the ball of your foot more in that environment.” 

Running Socks vs. Regular Socks

Both designers also mentioned key design elements of their socks that go beyond standard fit, best practices, and tested materials. Stance socks include a drop needle mesh, a lighter weight fabric with a lower thread count (hence the “dropped” needle), up top that allows heat and moisture to escape through the upper of a running shoe, an area with much more airflow than the bottom or sides. 

Bombas socks have an elastic cross-stretch that’s tightened just enough to keep the sock up without making it too restrictive and uncomfortable. The stretch begins above the ankle and spreads throughout the rest of the sock. It’s what keeps it from dropping beneath the ankle of the shoe and sabotaging any chance of the user besting their neighborhood nemesis in this year’s Turkey Trot. 

Running socks from top-tier brands are advanced, and months of research and testing go into their development. Five miles feels a whole lot different in a $20 nylon blended sleeve form fitted to hug one’s arch, ball mound, and ankle precisely. That said, great socks aren’t the whole equation. 

Jorgenson said that while socks are crucial and can go a long way in complementing running routines, they can’t redeem bad shoes. 

“If you don’t have the right shoes, it doesn’t matter what socks you’re wearing, you’re going to be miserable.” 

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The Best Running Socks, Chosen by a Marathon Runner

Each pair of the socks below was chosen by SPY Wellness Editor, Taylor Galla, who has run many miles in each pair. 

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