Understanding the Hair Fiber: What Is Hair Made Of?
Our hair is far more complex than it may seem. Its color, texture, thickness, shape, and density are unique to each person and are influenced by several factors, including genetics.
But what is really happening inside a strand of hair? And why is some hair stronger, drier, more fragile, or more sensitive to chemical treatments?
To properly care for the hair fiber, it is important to first understand what it is made of.
THE STRUCTURE OF HAIR
A hair strand is mainly divided into two parts: the root, located beneath the scalp, and the hair shaft, which is the visible portion of the hair.
The root is located within the hair follicle, a structure in the skin where the hair is formed and grows. At the base of the follicle, within the hair bulb, the cells responsible for hair growth and pigmentation are produced.
The hair shaft, on the other hand, is the part we can see and touch. It is primarily composed of keratin, a protein that provides the hair with its structure and strength.
THE HAIR SHAFT: 3 LAYERS TO KNOW
The hair shaft is made up of three layers: the cuticle, the cortex, and the medulla.
THE CUTICLE: THE HAIR’S PROTECTIVE LAYER
The cuticle is the outermost layer of the hair. It is made up of small keratin scales that overlap like the tiles on a roof.
It acts as a protective barrier against daily stressors such as heat, sunlight, water, chemical treatments, and mechanical manipulation.
Its condition directly affects the softness, shine, and overall appearance of the hair. A well-preserved cuticle helps keep the hair fiber smoother and more radiant.
THE CORTEX: THE CORE OF THE HAIR FIBER
Located beneath the cuticle, the cortex makes up the majority of the hair fiber. It is primarily responsible for several of the hair’s key characteristics, including its color, strength, elasticity, and shape.
The cortex contains keratin fibers connected by different types of bonds, including disulfide bonds. These bonds play an important role in the strength and natural shape of the hair.
When the hair fiber is repeatedly or severely exposed to bleaching, chemical treatments, heat, or mechanical stress, its structure can become weakened. As a result, the hair becomes more vulnerable to breakage.
THE MEDULLA: AT THE CENTER OF THE HAIR
The medulla is located at the center of the hair shaft. It is primarily found in thicker hair and plays a less significant role in the cosmetic properties of the hair than the cuticle and cortex.
KERATIN: AN ESSENTIAL PROTEIN
Keratin is the primary protein that makes up the hair. It contributes to its strength, structure, and resilience.
Keratin is made up of amino acids, some of which contain sulfur. These elements contribute to the formation of disulfide bonds that help maintain the internal structure of the hair fiber.
This is why the condition of the keratin and the overall structure of the hair is so important when performing color services, bleaching, smoothing treatments, or any other chemical service.
HAIR ALSO CHANGES WITH THE SEASONS
The hair fiber and scalp are constantly exposed to their environment.
In winter, cold temperatures, wind, and indoor heating can contribute to dryness and leave the hair more static-prone and fragile.
In spring and fall, some people may notice a temporary increase in hair shedding related to the natural hair growth cycle.
In summer, sun exposure, UV rays, chlorine, salt water, and heat can contribute to dehydration and weaken the hair fiber.
This is why hair needs can change throughout the year, and why your routine may sometimes need to be adjusted according to the condition of your hair.
UNDERSTAND YOUR HAIR TO CARE FOR IT BETTER
No two heads of hair are exactly alike. Even two people with the same hair type can have completely different hair fibers depending on their color history, chemical treatments, use of heat, environment, and hair care habits.
Understanding the hair fiber is therefore the first step toward caring for it properly.
At BLUSH, we believe every treatment should begin with a proper understanding of the hair. Because before choosing a treatment, you need to know what the hair fiber actually needs.
Beautiful hair doesn’t start with a product. It starts with understanding the hair.