John Davis

Written by John Davis


What is the Best Way to Treat Black and Bruised Toenail from Running?

Anyone who’s ever run a tough, hilly race or long run more than a few times, especially on trails, can probably guess what “jogger’s toe” refers to.

The black, bruised appearance of one of your toenails after it takes a beating during a run is accepted by some runners as an integral part of running, but when you have a black toenail, running becomes difficult, and if left untreated, knowing how to treat black toenail at home will be no help, as you will require more drastic treatment.

Injured toenails are not only painful and an ugly sight to look at, but can end up infected as well—the warm, moist environment inside your shoes is the perfect home for bacteria.


This week, we’ll be giving you the lowdown on runners toenail problems; how to treat black toenail from running, what to do if your toenail fell off while running, and if you most importantly, how long does a black toenail take to heal?

Black toenails from running are not only painful, but can end up infected or falling off. If your toenail hurts, this article will explain how common black toenails are for runners, what causes them so you can avoid black toenails in the future, and how to treat your bruised toenail correctly, so they can heal in less time.

How Common are Bruised Toenail From Running?

One survey of participants in a 1973 marathon reported that 14% of the runners suffered blisters, chafing, or loss of toenails that persisted for at least a week after the race.

A later study at the London Marathon found that only a few of the runners (0.1% total) treated at aid stations had toenail problems.

Both of these studies have their limits, of course, since a toenail problem alone is probably not serious enough to warrant a stop at an aid station, and subjects in the first study were probably more apt to respond to the survey if they’d suffered toe or skin problems.

The true prevalence of bruised toenail running injuries is probably somewhere in between these percentages, and is likely dependent on the distances and terrain that individual runners cover in their training and racing.

My Toenail Hurts: What Causes Runners Toenails to Fall Off?

According to a 2004 review article by E.A. Mailler and B.B. Adams, the cause of black or blue toenail from running is rooted in the repeated impacts that occur with each step.

After the initial impact with the ground, there is a brief moment where your shoe has come to a stop but your foot inside of it has not.

Your foot slides forward, usually only by a small amount, but this causes your toenails to take the brunt of the impact with the toebox of your shoe.

Additional stress is applied to your toenails when you push off from the ground, as your toes “claw” at the ground to gain additional propulsion.

Bruised toenail from tight shoes or shoes too big

As you might suspect, poorly-fitted or loosely-laced shoes can exacerbate the problem.

A shoe without sufficient room for your foot to slide forward will cause a more abrupt impact at your toenails, and a shoe with a toebox that is too low will push down on the top of your nails as you push off the ground.

Shoes that are laced too tight can compress the toenails as well, but conversely, a shoe that isn’t laced tightly enough will allow your foot to slide too far forward, banging your nails against the front end of the shoe.

It may seem like we are nit picking, but lacing your shoes correctly can make all the difference, and is an easy way to prevent black toenails from running in the future.

More downhill running means more bruised toenails

If you already have a black and blue toenail from running, downhills can magnify the problem, since they increase your speed and vertical impact force (and hence the momentum of your foot as it is sliding forward) as well as slanting your shoe downward, creating a ramp for your foot to slide down.

Long runs increase the chance of runners toenail problems

Longer runs and longer races obviously are more prone to cause problems with your toenails, since each step leads to additional stress on the nail.

The gradual swelling in your feet that occurs after you’ve covered many miles doesn’t help either, as it effectively reduces the size of your shoe.

Given all of the factors at play, it’s not hard to see why ultramarathoners, who often do 20 or 30-mile runs over hilly trails, are renowned for their ugly toenails.

If you are following a marathon training schedule, for the first time, you may notice more bruised toenail from running, but they are almost a rite of passage as a runner, so don’t panic!

Why your big toenail hurts the most

Mailler and Adams claim that the toes most commonly affected are the longest ones: the big toe, the second toe, and the third toe.

The relative lengths of these individual toes depends on the person, so if you have what’s sometimes called an “Egyptian foot” (where your big toe is the longest), you will  likely get blackened and bruised toenails on your big toe, whereas if you have a “Greek foot” (with either the second or third toe being the longest), these toes are more likely to get injured.

How to Help a Bruised Toenail: Bruised Toenail Healing Time

Mailler and Adams authored a later review of skin conditions in runners which detailed treatment and prevention options for jogger’s toe.

Correct fitting shoes

Keeping your shoes laced snug, but not too tight, and making sure the toebox is large enough to keep pressure off of your nails, even after extended periods of running where your feet have swelled up a bit.

Using an “ankle lock” lacing to secure your foot in the shoe can also be helpful, as it reduces the distance your foot slides inside of your shoe on footstrike.

Give your toes a little TLC

Keeping your toenails trimmed short and square (not curved) will also help evenly distribute stress on your toe.

If you’ve already got a blackened and bruised toenail, you can leave it alone if it isn’t bothering your running.

If  it is, you can try soaking in warm water to relieve some of the irritation.

Should you pop a blood blister?

According to Mailler and Adams, draining the fluid under the nail—either by puncturing the nail itself with a hot needle or draining it from the front, underneath the toenail, is somewhat controversial.

Generally, it is best to leave the toe nail as is and not try to release the pressure.

The pain should subside in a few days on its own, and attempting to pop the blood blister could result in infection.

We recommend visiting a doctor to be safe if you cannot handle the pain or pressure, but if you are determined to do this at home, here’s how:

Sterilize a paper clip by putting it over a flame and heating the tip.

While it is hot, place the hot end on the nail, which will quickly melt through the nail and create a hole by which the fluid can escape.

To be safe, after the fluid is drained, put some antibiotic ointment in the hole and on the nail.

During your bruised toenail healing time, consider this

You should be aware that some other skin and foot problems can masquerade as jogger’s toe.

Onychomycosis (or simply ringworm), a fungal infection of the nail, can also cause a toenail to appear discolored and bruised.

While it can be treated, albeit with some difficulty, as the fungus is embedded within the nail itself, it does need to be positively diagnosed by a doctor or, preferably, a podiatrist.

Additionally, melanoma, a serious cancer of the skin, can manifest underneath the toenails as well, making it sometimes hard to distinguish from a bruised toenail.

If your jogger’s toe doesn’t seem to be improving, or if it appears infected and swollen, you should see a doctor before the problem gets any worse.

Jogger’s toe can be an annoyance, but if you take care of your feet and make sure your shoes fit right, it doesn’t have to slow you down.

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1. Orava, S., About the strains caused by a marathon race to fitness joggers. Journal of Sports Medicine and Physical Fitness 1977, 17, 49-57.
2. Temple, C., Hazards of jogging and marathon running. British Journal of Hospital Medicine 1983, 29, 237-239.
3. Mailler, E. A., The wear and tear of 26.2: dermatological injuries reported on marathon day. British Journal of Sports Medicine 2004, 38 (4), 498-501.
4. Mailler-Savage, E. A.; Adams, B. B., Skin manifestations of running. Journal of the American Academy of Dermatology 2006, 55 (2), 290-301.

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10 Responses on “What is the Best Way to Treat Black and Bruised Toenail from Running?

  1. I understand that some ultra runners don shoes that are larger than they normally would wear due to the footswelling after many many hours on the trail. Is this recomended?

  2. Pics! 😉

    But seriously, you mentioned this under prevention, but “untrimmed nails” could also be listed under a cause.

    I also recently lost a nail due to a very long run in a new and apparently too small pair of yaktrax. They were just too tight and squeezed the shoe a bit, after 2 hours I just took them off and carried them.

  3. I recently switched from wearing a Nike Flex Run to a Nike Free Run and after a few weeks I have just started developing a bruised toenail on my right big tow. I have been running consistently for the past year, about 3-4 times a week and 4 miles per run. I have never had a problem with my toe until after switching to a new pair of shoes. I think the toe box is narrower and maybe has less volume. I hasn’t really bothered me much until today, which has been my 7th or 8th run in the new Nike Free. What’s your take on this? I spent 100 bucks on the new shoes so I would hate to have to ditch them and shell out more money again, but if that’s what it takes to continue running then so be it.

  4. i switched to Nikis. Noticed it had a narrow. I spent 4 months trying to break them in. My feet are bruised and battered. The nail on my little toe is infected. Not worth it. I’m on antibiotics to cure the infection. The nail will fall off later. Get rid of those shoes or you might suffer from them later.

    • Hi Patty, sorry to hear about your trouble with your shoes. We are big believers in comfort, and if those shoes do not work for you, then find a pair that do. As you have found, it is not worth ruining your feet for the sake of using a pair of shoes. Hopefully you have found a pair that works for you now.

  5. This is all interesring stuff! I only started running a year ago in a pair of Brooks Glycerin 12s but they were excruciating on my bunions, however I didnt really get much of a problem with black toenails. I recently changed to Altra Paradigm Zero Drop which have a nice big toe box. I’ve sussed how to pad my bunions in these which is great but now have real problems with black toenails!! The issue seems to be my foot sliding forward and my toes are taking a bit of a hammering. I ran 20k last night and now one of my big toenails is hanging off and been bleeding all day today. I have to tie the shoes fairly loosely to protect my bunions. Does anyone have any suggestions how to prevent the dreaded black toenails?!

  6. Hi,
    Recently ive seemed to start getting black toe nails but i dont run like the others and my shoes arent so tight neither too loose but are perfect fit the only reason i can think of getting black toe nails is because i walk alot. i walk home from college which is like a 40 minute walk and later on in the evening im at the gym could this be a cause of black toenails and how long should i wait before consulting a doctor? will ever heal automatically?

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