It comes up a lot, long after it’s been thoroughly debunked, but just in case you missed the memo: No, your nails and hair don’t continue to grow after death. Dying is undeniably grim but it, fortunately, doesn’t involve this bizarre, continued extrusion. So why does everyone think they do?
When you shuffle off your mortal coil and join the choir invisible, as some marvelous chaps once said in a pet shop, your body begins to dry out. This dehydration causes your skin, as well as other soft tissues, to retract, but your hair and nails remain intact. This, then, can sometimes give the appearance of growing hair and nails post-mortem, but it’s an illusion, nothing more. No more beautiful plumage for you, ex-human.
LiveScience explains that when you’ve breathed your last, there isn’t any material or hormonal activity left to induce any growth in your fingernails, toenails, or hair. No matter how much your lifeless body wants to alter its aesthetics, it won’t be able to – well, at least in this sense. You’ll still decompose quite dreadfully, of course.
There are far stranger things that really do happen to you after you die. As noted by Snopes, you may even make noises while you’re pushing up the daisies – but only because putrefaction-linked gas is trying to escape your corpse. Gizmodo explains that the contraction of muscles after you die, as well as the aforementioned tissue shrinkage, sometimes causes the unfortunate seepage of urine and fecal matter.
Either way, when you think about it, it’s quite the relief that nails and hair don’t continuously grow after they die. Imagine excavating a tomb to just find massive mounds of hair and networks of nails, like some strange monument to the Addams Family’s Cousin It.
According to the Guinness Book of World Records 2018, one Ayanna Williams of Houston has nails that are 576.4 centimeters (227 inches) long, the fruits of more than two decades of peculiar patience. Clearly, if fingernails grew after death, coffins would quickly resemble wooden, elongated porcupines.
It’s not clear where this myth started, but Snopes does mention that Vincent Price’s character in the 1959 movie The Tingler makes the claim. It’s also referenced in the tome “All Quiet on the Western Front”, albeit more fancifully.
In any case, it’s likely that the myth will persist for many years to come – it’s one of the more pervasive biological prevarications out there. Trust us, your hair wouldn't grow even with 4 million volts running through it.