Why Chafing Happens on the Trail

Chafing is caused by repetitive skin-on-skin or fabric-on-skin friction, made worse by sweat, moisture, and heat. On long trail runs, anything over 10 miles, even minor friction points compound into serious pain. The most common problem zones: inner thighs, underarms, nipples, waistband edges, and anywhere a seam or strap sits against skin.

The good news? Chafing is almost entirely preventable with the right combination of gear, lubrication, and a little pre-run prep.

Start With the Right Shirt

Your first line of defense is what you wear. Cotton holds moisture and creates drag against skin, it's the enemy on long runs. Moisture-wicking fabrics pull sweat away from the body and dry fast, dramatically reducing friction.

Two of our go-to options at Sloth & Duck:

• Unisex Performance Trail Tee — Built specifically for trail runners, this tee features moisture-wicking fabric and UV protection. Flatlock seams minimize friction points, making it a smart choice for long efforts.
• "Defy Everyone's Expectations" Moisture-Wicking Shirt — A performance crew neck that keeps you dry and moving. Lightweight and breathable for warm-weather runs.

Fit matters too, avoid anything too loose (excess fabric bunches and rubs) or too tight (creates pressure points). A relaxed athletic fit is the sweet spot for most trail runners.

The Anti-Chafe Product Lineup

Even with the right gear, lubrication is your best insurance policy on runs over 90 minutes. Here are the products trail runners swear by:

Balms and Lubricants

• Squirrel's Nut Butter — A cult favorite in the ultrarunning community. Made with natural ingredients, it goes on smooth and lasts for hours. Works great on thighs, underarms, and feet.
• Body Glide — The classic. A dry-formula balm that applies like a deodorant stick. No mess, no grease, and it holds up well through sweat. Great for nipples, inner thighs, and anywhere a waistband sits.
• SportSlick — A newer option gaining traction with long-distance runners. Silicone-based formula that stays slick even in wet conditions, useful for rainy trail days or river crossings.
• Trail Toes — Primarily designed for feet and toes, but works anywhere. Petroleum-based with a thick consistency that lasts through long efforts. A staple for ultramarathon runners managing hot spots and blisters.

Apply any of these liberally before you head out, don't wait until you feel friction. Reapply at aid stations on runs over 3–4 hours.

Taping Problem Areas

For high-friction zones that lubricants alone can't handle, athletic tape or kinesiology tape creates a physical barrier between skin and fabric. Common areas to tape:

• Inner thighs (especially for runners with larger thigh circumference)
• Underarms where a pack strap sits
• Heels and toes for blister prevention
• Anywhere you've chafed before, your body will tell you where it's vulnerable

Leukotape and KT Tape are popular choices. Apply to clean, dry skin at least 30 minutes before running so the adhesive sets properly.

Nipple Protection: The Real Talk

Nipple chafing is one of the most painful — and most common — issues for long-distance runners, especially men. Here's what actually works:

• Nip Guards — Purpose-built adhesive covers designed specifically for runners. Lightweight and low-profile under a shirt.
• Band-Aids — The budget option. Standard adhesive bandages work fine for most runs. Use the fabric kind for better adhesion through sweat.
• Second Skin + Band-Aid or Dr. Scholl's Corn Pads — This is the setup I personally use. Second Skin (a hydrocolloid dressing) goes directly over the nipple, then a Band-Aid or corn pad on top for extra cushion and adhesion. The corn pad's thickness adds a layer of protection that standard Band-Aids don't provide. It stays put through long, sweaty efforts and is gentle on skin when you remove it.

Whatever method you choose, apply before you feel any irritation, once nipple chafing starts mid-run, there's no comfortable fix until you're done.

Pre-Run Checklist to Prevent Chafing

• ✅ Wear moisture-wicking, flatlock-seam apparel
• ✅ Apply lubricant to all high-friction zones before you leave
• ✅ Tape any areas with a history of chafing
• ✅ Protect nipples with your preferred method
• ✅ Pack a small container of balm for runs over 2 hours
• ✅ Check your gear for worn seams or rough spots before long efforts

What to Do If You Chafe Mid-Run

If you feel the burn starting, don't push through and hope it resolves — it won't. At the next aid station or stopping point, apply lubricant directly to the irritated area. If you have tape, cover it. Wet skin chafes faster, so if you're sweating heavily or it's raining, reapply more frequently than you think you need to.

Post-run, clean the area gently with mild soap and water. Avoid tight clothing while it heals, and let skin breathe. Most chafing resolves within a day or two with proper care.

The Bottom Line

Chafing is a training problem with a gear-and-prep solution. The right moisture-wicking shirt, a solid lubricant, and a few minutes of pre-run prep can be the difference between a great long run and a miserable one. Build your anti-chafe routine now — before your next big effort demands it.

What's your go-to anti-chafe setup? Drop it in the comments — the trail running community runs on shared knowledge.