This professor measured his fingernail growth for 35 years. The results will amaze you!

By Seriously Science | April 13, 2015 6:00 am

Image:Flickr/Shannon Kringen

Image:Flickr/Shannon Kringen

Have you ever wondered how fast your fingernails grow? And whether they all grow at the same rate? Or perhaps you’ve noticed that your fingernails grow more slowly than they used to? If so, you and William B. Bean have something in common! Professor Bean painstakingly measured the growth of his fingernails for decades, and he published the minutia of these measurements after 20, 25, 30 and 35 years. The full texts of these papers are a delight to read. And the findings? Well, we’ll let Professor Bean speak for himself! (Be sure to check out the fantastically detailed chart of his fingernail growth rates below…)
“When I first began to measure the rate of nail growth, I scored marks on all my nails. Within a few months I found that each nail had its own pace. This was clearly distinguishable even by the rather crude method that I used. Some nails grew rapidly; some, in an intermediate phase, less rapidly; and some, slowly. The differences were small but regular. There was consistency in the variation, so if I applied a ratio I could tell by measuring one nail what the others were doing, and this I did on several occasions. In simple terms, toenails grow more slowly than nails of the hand, and the nail of the middle finger grows more rapidly than the nails of either the thumb or the little finger or the other two middle fingers.”

Nail growth. Thirty-five years of observation.

“A 35-year observation of the growth of my nails indicates the slowing of growth with increasing age. The average daily growth of the left thumbnail, for instance, has varied from 0.123 mm a day during the first part of the study when 1 was 32 years of age to 0.095 mm a day at the age of 67.”

We couldn’t leave you without another of our favorite passages and a figure from this fantastically written epistle!

“The kind of pleasure and understanding that I get from studying natural history has long vanished from most contemporary teaching institutions that have become part of intensive care units, which are supposed to save the residual intellectual machinery of medical students. The teeming mass of hope and pain, technical virtuosity, and depersonalization called a “health center” delivers packets of what is termed “medical care.” The capacity to look remains, but the capacity to see has all but vanished. Teachers and students forget that the ability to palpate is not the same as the ability to feel. As a gentle countercurrent, I set forth here this most recent five-year installment of the observations of thegrowth of my left thumbnail. It is a very long record of the growth of human deciduous tissue. Its duration has little precedent in clinical medicine or human natural history. Still, the nail provides a slowly moving keratin kymograph that measures age on the inexorable abscissa of time.”


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  • drturi

    Google UCI dr.turi for real answers about the human mind…

  • Joe Benten

    I guess I am not a normal “nail grower” then. Mine have increased in rate of growth as I get older. I used to trim them once every 2 weeks years ago now it is weekly and I cut more off now than before. Guess we all do have our own “things”!

    • Rachel

      That’s interesting– I also have the impression my nails grow faster than they did before. But I’m still in my thirties; maybe it’ll slow down again. I wouldn’t mind that, since as it is I have to trim them pretty often. I do find that my middle finger nails grow faster than the others, as Professor Bean also found.

  • Smarter than Your Average Bear

    I’m in my mid 60s and I could swear my nails are growing faster too. It’s too bad he did not correlate with diet

  • bensabio

    Interesting piece of diligence! Apparently the study ended in 1977, so this is not exactly recent news! When and where was the research published?

  • bensabio

    Oops…sorry I didn’t check the link to the papers before I posted that! The papers go back to 1962 and end in 1980.


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