What gives hair its kink or curl?

The natural wave pattern of hair is determined by the shape of the hair follicle, a tube-shaped canal beneath the scalp in which the hair shaft grows and eventually emerges.

A round-shaped follicle produces straight hair whereas at the opposite end of the scale, an oval-shaped follicle creates coiled hair. Kinks and curls can vary widely in appearance from ‘S’ to ‘Z’ shaped, and it is common for those with textured hair to have several different curl types on their head.