What Hair Is Made Of: Keratin and Protein

Hair is dead protein

The part of hair you see — what shows above the scalp — is not alive. It is made of a protein called keratin, the same protein in your nails. Because it is not alive, it cannot "heal" itself once damaged. That is why protection matters more than repair: once a strand breaks, it does not reconnect.

It also means hair care is two things: protecting what has already grown, and giving the root (which is alive, beneath the scalp) what it needs to produce new, strong hair.

Keratin, water, and natural oils

Healthy hair is not only keratin. It also holds:

Water — normal hair is about 10 to 15 percent water. Water is what keeps hair flexible and stops it from becoming brittle.

Natural oil (sebum) — the scalp produces an oil called sebum that coats the strand and helps it hold water.

When any one of these three — protein, water, or oil — is missing, hair becomes fragile and breaks more easily. Many hair problems are simply one of these three being out of balance.

Why this matters for you

Once you know hair is protein that needs water and oil, you can read product labels with new eyes. A "protein" product strengthens the structure. A "moisturizing" product adds water. An oil seals that water inside. You do not need everything — you need what your specific hair is missing. We cover this balance in Module 4.