“Hair and nails are dead.”

It's a common observation that our hair and nails don't hurt when we cut them, leading many to believe they are entirely lifeless structures. This everyday experience is indeed the root of the widespread belief that these parts of our body are completely dead. Unlike a cut to our skin, trimming our hair or nails involves no sensation of pain, making it easy to conclude that they must be devoid of any living components.

Scientifically, this popular notion is largely confirmed, but with an important distinction. The visible portions of your hair strands and fingernails, the parts you regularly trim, are indeed composed of dead cells. These cells are packed tightly with a strong, fibrous protein called keratin. This keratinized structure provides strength and protection, but because the cells themselves are no longer alive, they lack nerves and blood vessels, which is why cutting them is painless.

However, the story doesn't end there. While the visible parts are dead, the growth process relies entirely on living cells. Hair grows from follicles embedded in the skin, where living cells continually divide and push new hair upwards. Similarly, nails grow from the nail matrix, a specialized area at the base of your nail bed where living cells produce new nail tissue. These active, living regions are responsible for the continuous growth and regeneration of our hair and nails, even as the parts we see and trim are no longer alive. This dichotomy explains why the myth is so widely accepted, as the most apparent evidence supports it, yet the underlying biology reveals a more complex truth.