How to Prevent & Treat Black Toenail from Running


 Black toenail is one of the most common problems runner’s face when it comes to their feet, and they can happen to runners and race trainers of all types. 

Even if you’ve never had a it before, it is important to know what it is and how to prevent it if you are going to start training for any kind of race. 

Before we dive into detailed tips to help prevent and treat it, let's talk about what it is and the causes for it. 

5 Ways to Treat It Black Toe Nail Safely:

  • Try Toe Spacers. They can help absorb some of the pressure from running

  • Switch Your Running Shoe to One That Fits Properly

  • Trim Your Toenails 

  • Tie Shoe Strings Properly

  • Wear good socks

How to Prevent & Treat Black Toenail from Running

What Causes Black Toenail?

The first sign of it is a dark purple, green, or black color that appears under the nail and hurts when pressure is applied. This is a result of bruising under the nail from having too much friction with your running shoes. In most cases you will see it in your big toe before the other toes. 

Unlike a normal bruise, blood blisters that form underneath your nail have no room to swell or “breathe” so they tend to be more painful and take much longer to heal than a normal bruise. 

black toe from running

via the Cleveland Clinic

Many new runners panic and schedule a visit with their doctor. If the problem persists, I would recommend scheduling an appointment.

A quick 15 minute tele-health appointment with a doctor can provide a tremendous amount of additional information and guidance. 

Typically, they last until the nail falls off due to a new nail growing in.

While the biggest contributor is improperly fitted running shoes, they can also appear from wearing the wrong socks (which can also create blisters), doing a lot of downhill running, or from training intensely or for long distances at a time.

How to Prevent Black Toenail From Running?

  • The best way to prevent it is to make sure you have the right fitting shoes. Make sure you select shoes that are ½ to a full size larger than your regular size. There should be about a thumb’s length between your longest toe and the end of the shoe, and you you should have plenty of wiggle room for your toes.
  • Heat and humidity make your feet swell, which allows them to make more contact with the roof and front of your shoes when running. No matter what the climate is, your feet will most likely get hot and sweaty in your shoes when you are working hard, so make sure to wear quality moisture-wicking, temperature regulating socks, and avoid cotton socks.
  • Keep your toenails trimmed and clean. If you can feel your toenail making any contact with the roof or the front of your shoe when you run, that is the first sign of it potentially popping up.
  • Keep your feet moisturized with a good lotion or oil. This is a good way to keep your feet’s skin and nails healthy and less likely to separate from the pressure that’s applied to them from your shoes. Just don’t lather them up before you stick them in your shoes for a run, or else you will create a humid environment that is actually a contributor to the problem.
  • Toe Spacers are a good option that help reduce the impact. Here are the five toe spacers I recommend and the benefits of them
  • If you are running a hilly course, tighten your laces near the front of your shoes, to keep your feet more securely in place as you run up and down the hills. This helpful video shows you how to lace up your shoes to avoid it: 
  • Trim your toe nails. This is a biggie. Longer toe nails are more prone to black toenails
  • Tie your shoes correctly. The video below will help make sure you are doing it correctly. 
  • If you notice that your feet slide around a bit in your shoes, consider getting a rubber or gel insole, which tends to help keep your feet stay in place as you run.
  • As with every other part of your body, your nails benefit from having a healthy diet. Having a diet rich in calcium and biotin will help keep your nails strong and resistant to injury.
  • You can also receive these essential vitamins by taking a supplement, if it becomes a regular problem for you.

How to Treat Black Toenail From Running?

  • Treat it at the very first sign of bruising, and you might be able to save your nail from falling off completely. Treat the bruising with an antibiotic ointment and soak your feet in warm water mixed with peppermint essential oil, or a bath of peppermint tea. The use of peppermint is known to reduce hematoma (black deoxygenated blood) under the nail. Personal preference - I like to use the Majestic Pure Therapeutic Pepermint Oil.  It serves as a great anti-inflammatory and there is not a strong smell like other brands.  
  • If it’s too late to reverse the bruising, then the best way to treat it is to simply leave it alone and let it run the course. Do not force the old nail off or otherwise poke, pull or try to drain the blood. Doing so is painful, unnecessary, likely to cause infection, and will only prolong the healing process. Keep the nail bandaged and treated with antibiotic ointment until it falls of naturally.
  • If you are experiencing a lot of pain, notice redness, swelling or infection - see a doctor. Draining the blood from the nail is an effective way to reduce the pain and swelling, but should be done by a professional in a sterile environment.
  • This might be the toughest of the treatments - Lay off running while the nail is healing, and utilize cross-training workouts. Use a pool workout, a stationary bike, or strength training as substitutes. Don’t worry about losing a week or two of running, cross-training engages different muscle groups and can greatly increase your strength and endurance as a runner. It is recommended to utilize cross-training throughout your entire training process to prevent injuries of all kinds. You can resume running when it is no longer painful to do so, but make sure you keep the damaged nail tightly bandaged and treated with antibacterial ointment.
  • If the nail is partially disconnected from your nail bed, you can gently clip off the dead nail using sterilized clippers. You can also soak your feet in warm water mixed with Epsom salt to help keep it clean and aid in the falling off process.
  • Once the nail falls off, use a topical antifungal to make sure it grows back healthy. The prevents any fungal infection to form. It takes about six months for the nail to grow back completely, and will likely be a little thicker than it was before. While it is growing back, it helps to take a biotin supplement, which is proven to help nails (and hair) grow faster and look healthy. It will take about 4-6 months for the new toe to grow back in. 

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Hi, Jeremy Here, 

I am the the guy behind Train for a 5K. On this site, I share everything that learned along my running journey. The content I create is the running training I wish I had before we started this journeyAbout Me.