How to Avoid Black Toenails


Contrary to popular running lore, black toenails are NOT a requirement.

While flesh wounds are typically considered less severe than something like plantar fasciitis or shin splints, blisters and black toenails are injuries nonetheless.

Below let’s go through why, how, and what to do with black toenails.

Why do toenails turn black after running?

This bruising can happen with any toenail on any toe, but the umbrella cause is the toenail in question hits the upper or front of the shoe after that brief millisecond when the shoe has come to a stop on the ground and the foot is still moving forward.

When are toenails most likely to bruise?

Most often the case is that toenails may hurt after long runs. These workouts are usually trail runs longer than what you typically do and they may contain an extra-ordinary amount of downhill running.

How can you prevent toenails from turning black?

  • Tighten Your Shoes
    • If you’re running a race with lots of downhill running it’s a good idea to have your shoes a little more snug than you normally would. This will prevent your foot from sliding forward inside of the shoe as much.
  • Properly Sized Shoes
    • We usually recommend  half to a full thumb width of free space ahead of your toes for a shoe that is the correct size. Of course some like less and some like more, but that’s a nice start.
    • Shoes that are too small will leave the front of your toes right up closer to the toebox and ready to ram in to it.
    • Shoes that are too large will not be able to hold your foot in place within the shoe and your feet will move more again the front of the upper.
  • Trim Your Nails
    • While this does not solve the shoe issues, this can certainly go a long way towards
  • Proper Training
    • During longer runs when more fatigue is built up, you will begin to shuffle your feet more. This shuffling motion may increase how much your feet move within the shoe. You certainly need to do long runs, but do them within your abilities.
  • Downhill Running
    • Races or runs with an extra ordinary amount of downhill running may cause your feet to move forward within the shoe. While you don’t need to change to a different shoe, tying them a bit more snuggly can help prevent foot movement (which also can cause blisters!)

What do you do if your toenail turns black?

Best to let it be. It will run its course which is likely to be it falling off. Towards the end when it gets near to the end you may assist it’s departure. It may also be wise to bandage the toe a bit if it is bothering you and you continue to run.


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