Hair Texture

A strand of Caucasian hair has an average thickness of 0.07mm ( 3 in) and, seen in cross section, has an oval shape. Coarser Asian hair, about 0.09mm (3. S in) thick, has an approximately round shape, while African hair, ranging between 0.04 (1 . 6in) and 0.12mm (5in) in thickness, is extremely oval (nearly ' flat ').

It is generally no longer believed that the shape of a curly hair is caused by a curved hair follicle. The follicles of curly hair are, in fact, straight.

Further evidence that follicle shape has nothing to do with the curliness or straightness of hair is that some types of medication may cause curly hair to suddenly go straight, without any change to the follicle. All hair - even straight Asian hair - twists as it grows, but the more it twists, the curlier it is. African hair is the most fragile of the three hair types.

Hair product company L'Oreal's institute for ethnic hair and skin research considers the particular structure of African hair to be the reason for this. As mentioned, each African hair shaft has a distinct oval - almost flat shape. The outer cuticle scales protecting each hair are thinner in the areas where the oval shaped hair shaft is thinnest. As a result, these parts of the cuticle break easily, exposing the inner cortex of the hair. Once the more vulnerable cortex is no longer protected it then also breaks easily. In addition, the chemical composition of a part of the cuticle, prone to microscopic cracks, causes African hair to have weak mechanical resistance, according to L'Oreal scientists.

The weak points along the hair shaft and the spiral twists make African hair quite difficult to groom, and certainly more difficult to comb than straight Caucasian hair. It is also more brittle, splits more easily and has a lower moisture content. To straighten such hair, heavy-duty chemicals are needed, and damage is bound to occur to the hair structure. Asian hair is thicker than Caucasian hair and has about 10 layers of cuticle cells, making it stronger and stiffer with more body.