Chafing is more common than most runners admit. A study of 300 runners at the New York City Marathon found that 68% experienced chafing during the race, with the inner thighs, nipples, and underarms most affected. It starts as redness and irritation. Left unmanaged, it becomes raw, broken skin that stings in the shower and worsens with every kilometre.
The good news is that chafing is almost entirely predictable, which means it is almost entirely preventable.
Why it gets worse on long runs
Chafing follows a consistent pattern on longer efforts. The first 10 to 15 kilometres are usually manageable. Then it escalates, sometimes sharply, in the second half. This is not random. It reflects the cumulative effect of moisture and salt on the skin's resistance to friction.
As sweat accumulates during a run, the skin softens and becomes more vulnerable to shear. Salt left behind as sweat evaporates increases the abrasive load at the friction sites. Heat and humidity compound both effects. By the time a runner is into the back half of a marathon in warm conditions, their skin is significantly more susceptible to friction damage than it was at the start. The same fabric contact that was comfortable at kilometre five is genuinely damaging at kilometre thirty.
This is why chafing tends to be a long run and race problem rather than a training run problem, and why it catches runners out who have not experienced it before on shorter efforts.
The highest-risk areas
The inner thighs are the most commonly affected area, particularly in runners whose thighs make contact during the stride. Nipples are the second most common site, particularly in male runners wearing technical shirts where the fabric repeatedly crosses the nipple surface. Underarms follow from the repeated arm swing movement. Bra lines and waistbands are common sites for female runners. The neck and collar area can also be affected on longer efforts in cold weather when a jacket is worn.
Individual anatomy and running gait determine which areas are highest risk for a given runner. The practical approach is to identify your personal history of chafing sites and apply prevention to those areas first, then consider adjacent areas during longer efforts or in conditions that increase sweat load.
Fabric and apparel choices
Technical fabrics that move moisture away from the skin surface reduce the sustained skin wetness that accelerates chafing. Cotton holds moisture against the skin and creates more friction as it saturates. Cotton should not be worn next to the skin during running at any distance, and particularly not on long efforts in warm conditions.
Seams and tags in high-risk areas are worth inspecting before race day, not during it. A seam that sits across the nipple line or at the inner thigh is introducing friction independently of the fabric's moisture management properties. Turn garments inside out and run your hand along the seam lines in the areas that have chafed for you previously.
Fit matters. Clothing that bunches, shifts, or gaps during movement creates unpredictable friction. New race kit should be tested on training runs at race-relevant distances before being worn in a race.
Anti-friction balm: the essential step
Apply an anti-friction balm to every area where skin meets skin or fabric creates repeated contact before longer runs and any session in hot or humid conditions. Apply before you start sweating. Be generous. This is not an area where a light application is sufficient.
For nipples specifically, anti-friction balm or specialist nipple protection applied before the run eliminates most of the risk. Many male runners use tape across the nipples for races. Either approach works. The mistake is forgetting to apply anything and discovering the problem at kilometre 25.
Reapplication during ultra-distance events is worth the 30 seconds it takes at an aid station. At that distance, the cumulative salt load and skin softening from sweat has reached the point where a reapplication of anti-friction balm provides meaningful protection through the back half of the run.
During the run
Chafing gives you warning before it becomes serious. The hot, irritated feeling at a friction site during a run is a signal worth responding to. Stopping at an aid station to apply balm at the first sign of a hotspot is always better than pushing through and finishing with raw skin.
Adjusting clothing mid-run can also help. Pulling shorts down slightly to shift where a waistband sits, or rolling a sleeve to move a seam, can relieve a developing chafing site enough to get through a session.
After the run
Rinse chafed areas with clean, cool water after your run and pat gently dry. Avoid soap directly on raw skin as it will sting and can cause further irritation. Apply antiseptic to any broken skin and keep the area clean and dry between sessions. A recovery cream applied once the acute irritation settles will help restore the skin barrier and accelerate healing before the next run.
Premax Anti Friction Balm is formulated to reduce friction at the skin surface without blocking sweat glands or interfering with thermoregulation. Apply to inner thighs, underarms, nipples, bra lines, and any other personal chafing sites before every long run.
