Both hair and nails feel like "dead tissue" since they have no sensation, but they are actually made of protein produced by our bodies.

As a nutrition major, I often think, "The body really never rests" when I see things like this.

Especially since hair and nails grow every single day without us even being aware of it.

Starting with hair, it may seem simple in structure, but if you look inside, it is mostly made up of a tough protein called keratin.

You can think of it as the result of the protein we eat being digested and broken down into amino acids, which are then reassembled into hair.

This is why when there is a lack of protein or when the body's condition declines, the first thing that happens is that hair becomes thinner or falls out.

From the body's perspective, it decides, "Survival is the priority right now, so it's okay to reduce things like hair."

Conversely, when nutrition is sufficient and sleep is good, hair naturally becomes shiny and elastic. Nails are similar. Nails are also made of keratin, and they feel harder because they are in a more compressed form than hair.

When we cut our nails, we feel nothing, but if we slightly touch the skin under the nail, it hurts because there are no nerves in the nail itself. Nerves and blood vessels are all located in the part under the nail called the 'nail bed,' and the nail can be seen as just a layered protein plate stacked on top.

Interestingly, hair and nails serve as indicators of our body's health.

For example, if nails suddenly become brittle or grow unevenly, it may not only be a protein issue but also linked to a deficiency in minerals like iron and zinc.

The same goes for hair. Sudden hair loss or an increase in gray hair reflects nutritional status, hormonal changes, and stress levels. This is because when the body is under stress, it stops growth in the least necessary areas first.

On average, hair grows about 1 cm per day, while nails grow about 3 mm per month. As we age and hormonal balance changes, this growth rate slows down. I can definitely feel that the thickness of my hair and the texture of my nails are different now that I am in my 40s compared to my 30s.

From a nutritional standpoint, I want to emphasize that it is not just important to focus on protein, but also to have a balanced intake of nutrients like B vitamins, iron, zinc, and omega-3s for stable hair and nail growth.

No matter how diligently you consume protein, if other supporting nutrients are lacking, the efficiency of reconstructing protein into hair or nails decreases.

Ultimately, hair and nails are not just simple "protein masses"; they are like small records that reveal what foods I eat, how much I rest, and how much stress I experience.

When the body is in good condition, they grow quietly, but when something is out of balance, they are often the first to send signals.

So when I see hair falling out while washing my hair in the morning, I can't help but check my health once again.