Styling hair has rules you can use or bend to express yourself. However, breaking these rules can cost you.
Before you reach for a flat iron to straighten your curls or put fun curls back into your straight hair, you need to know about the structure of the hair.
The hair shaft is the visible part of your hair that grows out of a sack you know as the hair follicle. Below the surface, you have other structures that determine the health and function of your hair including arrector pili muscle and sebaceous gland.
The shape of your follicles has the most impact on how straight or how curly your hair is. Round follicle shapes produce flat hair, and oval ones produce curly hair. The flatter the oval shape is the curlier the hair becomes.
The angle of the follicle about the scalp plays another role. Think of a follicle as a tunnel. When the tunnel travels straight up, it produces straight hair. When it angles up, it produces curly hair.
The natural, healthy oil of sebaceous gland is called sebum. When the tunnel is angled, sebum doesn’t travel well along the hair shaft. Less oil leads to dryness in curly hair.
Hair care products and flat irons cannot change the shape of the follicles, its angle and how sebum travels. Those are the anatomical and biological rules you need to work with.
What can you do to express your mood and style is within the shaft?
There are three layers in the hair shaft. Cuticle, cortex, and medulla. Heat, water, and chemicals impact the bonds within these layers. Think of these bonds as glues.
Softening or destroying these bonds or glues make it possible to reshape and style the hair temporarily.