Why Running Shorts Have Built-In Underwear


Have you ever wondered why running shorts have built-in underwear?

When I first bought a pair of running shorts, I was always curious as to what these thin net-like underwear are for. At first, I found them annoying and useless but after doing my research as to what they were and wearing them on multiple runs, I finally understood how good they are and why they are there in the first place. 

Ahead, we will discuss what they are, the advantages they bring to the table, and if you need to wear underwear under them. 

What Are Those Built-in Underwear?

The built-in underwear inside running shorts is called a lining. They are made with special fabric designed to wick away the sweat and moisture in your crotch area which helps keep you fresh and dry throughout the run. 

The linings in these types of shorts are usually thin and loose-knit making them more breathable than your typical underwear. 

There are two kinds of lining. One looks like regular underwear and the other looks more like compression shorts.

Both types are great at keeping sweat and moisture away from your body but the former offers more breathability while the latter offers more protection from chafing.

By the way, I actually found a pair of running shorts that I really like. It has a long compression short type of lining which eliminates any possibility of chafing, and they’re cheap. They’re called Lixada 2-in-1 running shorts and you can buy them on Amazon

Are Lined Shorts Better?

Whether lined shorts are better than unlined shorts or not depends mostly on personal preference. I have friends who only wear lined shorts but I also have some who hate them for their own personal reasons. 

There are many advantages to wearing lined shorts over linerless running shorts. 

You don’t have to worry about your underwear – Because lined shorts already serve as your underwear, there’s no reason for you to find good running underwear to wear under your running shorts. 

Reduces chafing. Chafing is a result of skin-to-skin or skin to fabric friction which can be exacerbated by sweat or moisture. Because the linings are great at absorbing and drawing off the sweat, it also helps reduce chafing. 

More breathable. Because the linings are made of thin and loose-knit fabric, air flows in your crotch area better which helps you feel fresh and cool even on longer runs. 

Prevents a hungry butt. Have you ever experienced having to pull out your shorts or underwear because your butt is “eating” them? I have found that to occur less when I’m wearing lined shorts. 

However, you can also achieve all these advantages using linerless running shorts by simply using good running underwear like the Runderwear

Related post: Best Running Underwear For Men That Prevents Chafing

Do You Need to Wear Underwear if You Wear Lined Shorts?

The short answer is no, you don’t need to wear underwear if you’re wearing lined shorts. 

The lining already serves as your underwear. They keep it fresh and breathable inside your crotch area that helps with the overall comfort and feeling. 

Wearing underwear inside lined shorts will make it completely useless because you’re not going to benefit from the moisture-wicking properties and breathability of the shorts’ lining. 

But in case you’re uncomfortable with going commando, here’s what you can wear under running shorts. 

Can You Cut The Lining?

Yes, you can cut the lining out of your running shorts.

Simply pull out the lining from the inside and cut nearest to where they’re sawn. 

How to cut running short lining

But I don’t see any good reason as to why you should cut them out. I suggest you just buy a new pair of unlined running shorts and try both of them on separate occasions to see what you prefer. 

Final Thoughts

Running is a great way to stay away from life-threatening diseases plus other great health benefits. It is one of the most effective and accessible exercises in the world. 

You don’t need much to start running. All you need is a good pair of shorts and shoes and you can hit the road and make yourself healthier. 

I hope this article helped you find out more about what the underwear built inside running shorts is. 

Lined vs unlined shorts
Lined vs unlined shorts

Recommended Gear

I understand that looking for the right running gear is difficult. There are hundreds of product reviews out there recommending 10 or more products that do not seem to help narrow down your buying decision.

That is why I created a recommended product page with only 1 to 3 recommendations per running gear. That way, it’ll help narrow down your choices to only a few products that are guaranteed to give you great value for your money.

I have researched and tested these products and I’m constantly updating the page if I see something better. You can visit the page by clicking this link.

Nicho Mauricio

Running wasn't always my favorite sport. I was a CrossFit athlete and I loved every bit of it. But since the pandemic began, I was forced to stay away from the gym and train at home instead. Things got boring. That's when I decided to trail run with my friends. I instantly got hooked. So I started training and researching all things running. As a beginner, I want to buy only the best running gear and do only the best practices. This blog is where I share what I've learned in my journey and my experiences as a runner.

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