What makes curly hair curly (or straight hair straight)

Have you ever wondered why you have curly hair, while a friend of yours has pin straight hair? What is it that makes curly hair curly and straight hair straight? Let’s find out 🙂

Cross section of your hair strand

Cross section depends on the hair follicle that the hair strands emerge from. A round follicle produces a cylindrical hair strand. An oval follicle produces a ribbon like compressed flat hair strand. You must have noticed how a rope falls down straight when held up, whereas a ribbon curls up 🙂

Shape of your hair follicle

The bulb is the bottom most part of the hair follicle. People with curly hair usually have a hook shaped bottom and so the hair grows out at an angle.

The number of disulfide bonds in your hair

Keratin (your hair protein) has sulphur. Curly hair has many disulfide bonds because in a flatter hair strand, there is a larger area and hence a larger probability of sulphur atoms to form bonds. A disulfide bond is strong enough to pull the hair into a wave or curl. When you pull out a curl, it curls back because the chemical bond is that strong. This is why heat or chemicals are used to alter the structure.

That’s some science 🙂 You may want be interested in this  – My curly hair routine 🙂 or check out Why is curly hair dry?