Guide · Feet
How to prevent blisters when running
Quick answer
Running blisters come from repeated shear and friction on skin softened by sweat. The most reliable prevention is dry feet in synthetic or wool socks, shoes that fit and are broken in, managed calluses, and covering known hotspots with tape or a blister patch before you run. If a blister forms, leave it intact and cover it.
- Blisters occur in up to 39% of marathon runners and account for more than 70% of medical visits in multi-stage ultras (Lipman et al., 2014).
- A history of blisters is a major risk factor for getting more, so protect known hotspots first.
- Avoid cotton socks; the AAD recommends moisture-wicking or nylon socks.
- Tape and patches are low-risk and helped in one randomized trial, but results across studies are mixed.
Why runners get blisters
A friction blister forms when repeated rubbing makes the outer layers of skin shear against the deeper layers until they split and fill with fluid. A 1995 review in Sports Medicine notes that moist skin makes this worse, because damp skin has more friction than dry skin.[1] That's why sweaty feet in long races are so prone to blisters.
Heat, long distances, downhill running that pushes toes forward, new shoes and grit inside the shoe all add to the load on the same small patch of skin.
How common are blisters in marathons and ultras?
Very. Blisters occur in up to 39% of marathon runners and account for more than 70% of medical visits in multi-stage ultramarathons, according to the Pre-TAPED trial authors.[3] In one 219 km (136-mile) stage race, 76% of runners had blisters by day four, and 65% of those blisters were on the toes.[5] In a study of 533 French trail ultra runners, 29% reported blisters, and runners with a history of blisters were far more likely to get them again.[6]
Prevention steps that matter most
- Socks: choose synthetic or wool running socks, not cotton. A review of military and athletic studies found acrylic socks and a thin liner under a thicker sock reduced blisters.[1] The AAD advises against cotton.[7]
- Shoe fit: wear shoes that are broken in and leave room for the foot to swell late in a race. Thumb-width space in front of the longest toe is a common rule for trail descents.
- Keep feet dry and clean: remove grit early and change socks when feet have been wet for hours.
- Manage calluses: thick calluses can blister underneath. File them down gradually rather than cutting them.
- Cover hotspots before you start: if a spot has blistered before, cover it with tape or a hydrocolloid blister patch before the run.
Do tape and blister patches work?
The evidence is mixed but encouraging. In a randomized trial of ultramarathon runners, paper tape applied before the race reduced blisters by 40%.[4] An earlier trial in the same kind of race found no significant difference,[3] and a stage-race study found that taping, powders and lubricants did not lower blister rates.[5] A 2016 review concludes that taping and low-friction patches are plausible but need more research.[2]
Our view: covering a known hotspot costs little, carries little risk and helps many runners. Test it in training so you know it stays on. See how hydrocolloid patches work.
What to do when you get a blister
The American Academy of Dermatology advises against popping a blister because the roof protects the skin underneath from infection.[7] Cover it loosely or with a hydrocolloid patch, which the NHS says can protect the blister and help reduce pain.[8] If a blister is large and very painful, the AAD describes draining it at the edge with a sterilized needle while leaving the roof in place. Most blisters heal on their own within about a week.[8]
People with diabetes or poor circulation should ask a clinician before treating foot blisters, and anyone should seek care if a blister shows signs of infection: spreading redness, warmth, swelling or pus.
FAQ
Should you pop a blister from running?
Generally no. Leave it intact and cover it. If it is large and painful, drain it at the edge with a sterilized needle and keep the roof on, as the AAD describes.
Do double-layer socks prevent blisters?
Some studies found a thin liner under a thicker sock reduced blisters, but evidence is limited. Moisture-wicking material matters more than layer count.
Does lubricant on the feet prevent blisters?
Results are mixed. Lubricant reduces friction at first but can increase it later as it soaks into the sock. Many runners prefer tape or patches on known hotspots.
Sources
- Friction blisters: pathophysiology, prevention and treatment. Knapik et al., Sports Medicine, 1995.
- Etiological foundation for practical strategies to prevent exercise-related foot blisters. Hoffman, Current Sports Medicine Reports, 2016.
- A prospective randomized blister prevention trial assessing paper tape in endurance distances (Pre-TAPED). Lipman et al., Wilderness & Environmental Medicine, 2014.
- Paper tape prevents foot blisters: a randomized prevention trial assessing paper tape in endurance distances II (Pre-TAPED II). Lipman et al., Clinical Journal of Sport Medicine, 2016.
- The enemy of the feet: blisters in ultraendurance runners. Scheer et al., Journal of the American Podiatric Medical Association, 2014.
- Epidemiology, prevention methods, and risk factors of foot blisters in French trail ultramarathons. Damoisy et al., Journal of Sports Medicine and Physical Fitness, 2023.
- How to prevent and treat blisters. American Academy of Dermatology.
- Blisters. NHS.
