Why Do Fingernails Grow Faster Than Toenails?

Toenails grow faster in summer when our circulation is at its best. (Photo: Sergey Ryzhov/Shutterstock).

Not a lot is known about the exact biological mechanism that causes fingernails to grow faster than toenails, but one thing is for sure — they definitely do grow at a faster rate, three to four times as fast to be exact. In fact, to give the impression to my kids’ teachers that I regularly groom them (and therefore am a responsible parent), I regularly cut my kids fingernails once a week, but thankfully only have to cut their toenails once every two weeks. So what gives?

Before we can understand why fingernails grow faster, we need to understand how they grow. Nails are comprised of a protein called keratin. Each nail begins growing out of a little pocket under your skin, called the nail matrix. The matrix is constantly making new cells and pushing the older ones up and out over the little patch of skin underneath your nail called the nail bed. Once those cells are pushed out of your skin, they’re already dead, which is why it doesn’t hurt to cut your nails.

The lunula is the whitish half-moon shape that you may see towards the bottom of your nail. If it is damaged, your nail will likely be permanently deformed. If you don’t see your lunula, don't worry, it’s there, just underneath your cuticle. Some people with smaller nails may only be able to see it on their thumbnails.

Dr. William Bean, a physician at Walter Reed Army Medical Center in Washington, D.C., conducted a longitudinal self-study on his own nails during much of the 1900s. Starting at the age of 32, Bean scratched a line on his nail from where it emerged from his cuticle on the first day of every month. (He actually had a baseline dot tattooed on his nail as well.)

In this manner, he tracked his nail growth for more than 20 years, after which time he discovered that his overall rate of nail growth had slowed by over a month. This observation led him to conclude that nail growth has to do with blood flow and metabolism, which slows as we age. Indeed, it is documented that the nail growth of adults is slower than the nail growth of kids. Hence why I’m always clipping, I suppose.

After the publication of Bean’s study, Dr. Rodbey Dawber, an Oxford dermatologist, performed his own experiment after he injured his left ring finger in a rugby match. He found that the splinted finger’s nail growth was slower than that of his other fingers, which saw regular use.

Other studies have also shown that if you’re right-handed, the nails of your right fingers grow stronger than your left and vice-versa.

Because of all of this research, scientists deduce that since your fingers are used so much more often than your toenails, the nails of your fingers grow faster than your toenails. It also has to do with how exposed they are as well. Some also say that since your fingernails are closer to your heart, and therefore have increased blood flow, that may be a factor in their rate of nail growth as well. This also helps explain why nails tend to grow faster in the summertime, when our circulation is at its best.

Any way you slice it (or trim it), fingernails have a definite edge over toenails, and will continue to unless most of us start to type with our toes.