What is Chafing?

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What is chafing?

Chafing is a friction-induced skin injury where the outer layer of skin (epidermis) is rubbed creating microscopic tears, exposing the skin layer below (dermis), which becomes red, raw and irritated.

Runners are more susceptible to chafing, along with other endurance athletes, due to repetitive movement, generated through skin-to-skin or clothing-to-skin contact of multiple body parts, combined with sweat.   Chafing causes an extremely painful burning feeling, particularly during your post-run shower!

 What causes chafing?

 Chafing is exacerbated by:

  • Moisture

Excess moisture from sweating, water sports such as a triathlon swim or damp weather conditions will increase the likelihood of chafing.  Salt residue from perspiration or seawater will aggravate the situation, acting like sandpaper, grinding and irritating the skin.

  •  Poor-fitting clothing

Clothing that is too baggy or tight including socks will rub and make you more susceptible to chafing. Proper-fitting, moisture-wicking clothing that is ergonomically designed to move with you will prevent chafing and ensure you enjoy a comfortable run.

  • Clothing with bulky seams

Clothing with thick seams will aggravate chafing.  Choose clothing that is seamless or has flat seams in the areas that are prone to chafing.

  • Clothing that prevents skin from ‘breathing’

Some clothing material, such as cotton, is more likely to hold sweat and moisture next to the skin, causing chafing. Choose clothing that is made of moisture-wicking fabric, which transports moisture away from the skin and is created using mesh panels for increased breathability.

  • Dehydration

If you are dehydrated, your body is unable to flush salts away from your skin as easily.  Drink lots of water before, during, and after exercise, allowing you to perspire freely so the perspiration doesn't dry into salt crystals that can enhance the chafing.  


Runderwear – chafe-free guaranteed!


Runderwear performance clothing comes with a chafe-free guarantee.


Runderwear’s award-winning range of chafe-free clothing is:


Seamless design

Most Runderwear clothing is seamless to prevent rubbing and chafing.  Where seams are vital within the design, seams have flatlock edging, again to minimise skin rubbing.


All Runderwear clothing is created using mesh panels of micro-perforations to control air-flow, increasing breathability of the skin, maximising comfort and enhancing the lightweight, moisture-wicking properties of the fabric.

Moisture wicking

All Runderwear clothing is made using technical moisture-wicking Polyamide fabric, a highly effective material, which transports moisture away from the skin, preventing chafing mile after mile.

Ergonomically designed for ultimate comfort

All Runderwear clothing is ergonomically designed to fit your body shape and move with you, providing the ultimate in comfort.  Runderwear also contains high-grade Elastane to ensure your clothing continues to fit properly, even when hot weather causes swelling. 


All Runderwear clothing is designed to be lightweight.  Running in the heat increases exertion levels, so you want to remain as light as possible to retain fluid and energy. Many people consider the weight of their trainers, but choosing clothing made from a lightweight fabric for underwear, socks, shorts and base layers can really make a difference.


Top Tip - And remember as well as wearing your Runderwear, make sure you are drinking plenty of water, especially in the heat, to minimise chafing.

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243 reviews

These socks are the best running socks I have ever purchased

Good service, product is fit for purpose

Service is great, and the boxer shorts are good for running and so the job they are designed for. Little disappointed that they are not ethically sourced, they have a cheapish feel to them which was a surprise.

Thank you for your feedback Duncan. Runderwear's range of seamless underwear has sustainability benefits over cut and sew garments by reducing wastage of fabric at manufacturing stage. We are testing new fabrics that have been made using sustainable fibers and aim to bring these into our range in the near future. All our factories are quality control checked to the highest standard and our small team regularly visit them and are satisfied that working conditions are ok. We are somewhat surprised you find the pants have a cheapish feel to them. But maybe you mean that the material is not thick and when you stretch it and look up-close it has an almost gauze-like appearance; this is the nature of the product and gives it the moisture wicking properties. We hope you will like using them and will realize how comfy they are.



Super comfy and stay in place. U.K. size 10 and ordered small.

Women's Running Long Shorts
Cassandra Kay-Lewis
At last... chaff free running.

Had just about given up with the belief there were running shorts out there that don’t chaff. Purchased the long shorts, and have to say they are wonderful. They are stable, breathable, comfortable and total chaff free.
I would like to highlight I was under the impression that these were “proper” shorts, however they could possibly be described as a base layer shorts. Some form of lightweight run shorts are recommended to wear over them to cover your modesty. Wearing my lightweight run shorts over the top of them didn’t detract from the long shorts benefits.
I typically run up to 21km.