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Hair shape varies widely among races and individuals, and hair shape is generally divided into three main categories: straight, wavy, and frizzy.
Hair Composition
Hair shape varies widely among races and individuals, and hair is generally classified into three main types: straight, wavy, and frizzy.
When hair is viewed in a ring, it is composed of a three-layered ring of hair follicles, cortex, and hair medulla. Human hair has a large proportion of cortex, which is a bundle of fibrous proteins. Most of its components are proteins called “keratin,” and its hardness is about the same as that of a fingernail. It is relatively resistant to heat.
During the process of building hair cortex, an amino acid called cystine (*1) contained in keratin chemically bonds (disulfide bond) with cystine in other keratin molecules, and the keratin molecules are tightly bound to each other. This helps to maintain the toughness and elasticity of hair.
Japanese with “straight and thick hair
Generally speaking, yellow people, including the Japanese, have straight hair, Caucasians have wavy hair, and black people have frizzy hair. Ninety-two percent of Japanese have straight hair, which is round in cross-section, while wavy hair, which is more common among Westerners, is oval in shape, and frizzy hair is flattened, like a squashed circle.
Straight hair with a round cross-section is the thickest, but the thickness of Japanese hair ranges from 0.05 to 0.15 mm, with fine hair measuring 0.05 mm, normal hair 0.08 to 0.09 mm, and thick hair around 0.12 to 0.15 mm.
The nature of hair is not constant.
The aforementioned hair thickness is not the same throughout life.
Hair grows thicker and thicker between the ages of 14 and 24, when it grows best, and after the peak period (around age 20 for men and around age 25 for women), it gradually becomes thinner and thinner. It is easier to understand this if you compare the hair of an elderly person with that of a person in his/her 20s.
Also, within the same head of hair, there are different types of hair with different properties, from thick to thin, from hard to soft. This is determined by the thickness of the outermost hair follicle, which is thicker and harder, and thinner and softer.
Although the thickness of hair varies with aging, individual characteristics, and the progression of hair loss, we should take care of our hair correctly on a daily basis and keep it thick and lustrous for the rest of our lives.
