It’s a bit morbid to think about, but ever wonder what happens to the body after the heart stops beating? You’re not alone: Humans have created dozens—if not hundreds—of theories about what the body does after death.
One such theory gained traction after it was printed in the 1928 novel All Quiet on the Western Front by Erich Maria Remarque. The narrator imagines a deceased friend’s nails growing like corkscrews and the hair lengthening like “grass in good soil.”
More recently, the late comedian Johnny Carson once joked on his show, “For three days after death, hair and fingernails continue to grow—but phone calls taper off.”
Sorry, Carson, but the only true part of that joke is that you definitely won’t be making calls from the grave. Processes of the body—such as metabolism, menstruation, sweating, the immune response, sexual arousal, or (yep) the growth of hair, nails, and everything else—are all controlled by hormone regulation in the endocrine glands (such as the adrenal or thyroid gland).
Without oxygen, nutrients, and fuel from calorie intake, bodily processes come to a halt. That means no digestion, no sweaty pits, no need to pee, and definitely no need to clip your nails or trim your hair.
Both the hair and nails are formed from an essential protein called keratin, according to the U.S. National Library of Medicine. Keratin is produced by hormones from the endocrine system. No hormone regulation means no keratin to produce new nail or hair cells.
But to be fair, this myth stems from a very real phenomenon: The skin dehydrates after death. Imagine a dry sponge, tight and shriveled up (sorry for this grotesque imagery). Likewise, the dehydrated skin retracts around the nails and hair follicles, which can make your hair and nails *look* longer, even if they haven’t technically grown.
Think of it this way: Even when the endocrine glands are functioning normally and producing keratin, your nails only grow 2.5 millimeters a month. It would be impossible for the nails to be noticeably longer within the three days after death—as Carson’s joke implied—by just keratin.
In other words, you can go ahead and cancel that postmortem manicure.
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