The Truth About Hair and Nail Growth After Death: A Deep Dive
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Chapter 1: Understanding the Myth
Do hair and nails genuinely continue to grow after death, or is this a myth that needs to be put to rest once and for all?
“I should keep my nails trimmed short; otherwise, they might grow so long after I'm gone that they burst through the coffin!” (By the way, the white feather is often seen as a symbol of death.) Photo by Mona Eendra.
How does our body determine the moment of death?
This intriguing question will likely provoke a variety of responses, depending on whether you consult a religious leader, a philosopher, or a scientist.
At a cellular level, do some functions persist long after consciousness has departed? Once the heart has ceased to beat and brain activity has halted, are there still some cells in our body operating without realizing that their time is up?
One argument supporting the notion of “zombie cells”—body parts that remain oblivious to the death of the whole—is linked to our hair and nails. There's a common belief that after we die, our hair and nails continue to grow.
Is this a creepy reality, or merely a ghostly tale?
Section 1.1: Fingernails and Hair: An Intriguing Connection
Despite their different appearances and textures, both hair and fingernails are composed of the same material: keratin.
Keratin is a structural protein that resembles a long, twisted ribbon. Two keratin molecules intertwine to create a dimer, forming a strand that resembles DNA. Numerous strands then weave together to create a robust, flexible material, which can take the shape of long strands (as seen in hair) or flattened sheets (like fingernails and toenails).
Most of the makeup of nails and hair is keratin, although layers consist of dead, flattened cells. As our nail beds or hair follicles generate new cells, older cells get compressed, contributing to the hard, scaly structure that is expelled.
Here are some additional fascinating facts about hair, fingernails, and toenails:
- Fingernails grow at an approximate rate of 1 millimeter per day, totaling around three and a half centimeters each year.
- Fingernails grow faster than toenails, and if one hand is more frequently used than the other, its nails may grow quicker.
- Despite their hard appearance, fingernails are porous and can absorb oxygen or harmful substances.
- Nails can detach due to disrupted blood supply, often resulting from a crushing injury.
- Researchers are exploring the possibility of sequencing DNA from the dead, compressed cells found in nails, instead of using blood samples for easier DNA collection.
Section 1.2: The Reality of Growth After Death
So, what’s the verdict on post-mortem growth? Do our hair and nails truly continue to grow after the heart stops and brain activity ceases?
While it seems that hair and nails lengthen after death, this phenomenon has been noted for centuries, leading many to believe that these body parts continue to grow.
However, this is not the case. After death, hair and nails, like every other part of the body, stop growing almost instantly.
This aligns with biological principles. Like all cells in the body, those responsible for producing hair and nails depend on nutrients and oxygen delivered through circulating blood. Once the heart stops, blood flow halts, meaning these cells receive no new nutrients, leading to cell death.
So why do hair and nails seem to extend?
The answer lies in dehydration. After death, the body begins to dry out, much like a sponge that has been removed from water and left to dry. As this occurs, the skin shrinks, pulling away from hair follicles and nail beds.
While hair and nails do not shrink, the skin retracts, making it appear as though they are protruding more than before, even though there’s no actual growth.
Morticians are well aware of this phenomenon and use special creams on recently deceased bodies to maintain moisture and prevent the appearance of excessively long nails and hair during funerals.
Thus, this myth is debunked. Hair, toenails, and fingernails do not grow after death; rather, it is the surrounding skin that dries and recedes, making these parts seem longer than they truly are.
Even though they appear lifeless, remember that our hair and nails are living at their base. Exposing them to harmful substances can have adverse effects on health, as they are porous and can absorb harmful chemicals. Caring for our nails can lead to improved health.
Upon death, our cells begin to perish almost immediately. White blood cells are among the last to die, typically within 72 hours. Any changes occurring in the body after three days are due to decomposition, not because any cells are still functioning.
Sam Westreich, PhD in genetics, focuses on studying the gut-associated microbiome and currently works at a bioinformatics startup in Silicon Valley. Follow him on Medium or on Twitter at @swestreich.
Have a science question? Leave a comment to suggest a topic for my next article. Also, check out this related piece:
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