What is Hair Made Of?

Have you ever stopped to think about what makes up your hair? Hair is one of the most visible parts of our bodies, yet many of us take it for granted. In this article, we’ll explore the composition of hair, how it grows, and the many functions it serves.

What makes up hair?

Special cells in our hair follicles called keratinocytes produce keratin, a protein that forms the structure of the hair. These cells create keratin and push the hair out of the follicle onto our scalp, where it grows longer.

The structure of hair

Hair consists of three layers: the cuticle, the cortex, and the medulla. The outermost layer is the cuticle, which consists of overlapping scales that protect the cortex, the thickest layer of hair. The cortex contains most of the hair’s pigment, which determines hair color and texture as well as its strength. The medulla, the innermost layer, is present only in some types of hair.

Is hair of different colors made differently?

Hair comes in a variety of colors and types. The texture and curl pattern depend on the shape of the hair follicle. Straight hair has round hair follicles, while curly hair has oval or flat-shaped follicles. The size of the follicle determines whether hair is fine or coarse. The amount of melanin in the cortex determines hair color, with more melanin resulting in darker hair and less melanin resulting in lighter hair. A different pigment called pheomelanin causes red hair. Hair color can also change due to age, genetics, and exposure to chemicals and UV radiation . As people age, hair follicles produce less melanin, resulting in gray or white hair.

How does hair grow?

Hair grows in a cycle that lasts from two to six years. During the active growth stage, known as the anagen phase, keratinocytes produce keratin and push the hair out of the follicle. Then, the hair enters the transitional phase known as the catagen phase where the hair stops growing, and the follicle shrinks. Finally, the hair enters the telogen phase, where it rests for a few months before falling out. After the hair falls out, the cycle starts again, with a new hair growing in the follicle.

Now you know the composition of hair and how it grows. Hair is an incredible part of your body, and it’s important to care for it by washing it regularly and eating a healthy diet. So the next time you’re brushing your hair or getting a haircut, remember all the science that goes into making your hair look and feel amazing!

Flesch Grade Level: 7.7

Flesch Reading Ease: 67.7

Glossary

Follicles: Small cavities in the skin that hair grows out of.

Keratinocytes: Cells in hair follicles that produce the protein keratin.

Cells: The basic unit of life and the building blocks of all living organisms.

UV radiation: Ultraviolet radiation; a type of electromagnetic radiation that has a shorter wavelength than visible light and can cause damage to living cells.