Hair is made of a protein called keratin. It grows from a follicle in three layers:
•The cortex, the middle layer that contains the pigment (melanin) and determines hair strength and elasticity.
• The cuticle, the outermost protective layer made of overlapping scales.

The condition of the cuticle is crucial. When it's smooth and flat, hair looks shiny and healthy.
Damage from heat, chemicals, or friction can raise the scales, making hair appear dull and frizzy.

Almost every salon service involves chemistry:
• Coloring: Hair dyes use ammonia to swell the hair shaft and open the cuticle. Hydrogen peroxide then breaks down the natural melanin and activates the dye molecules to deposit new color in the cortex.
• Perms and Relaxers: These services chemically alter the hair's structure. Perms use chemicals to break and reform the protein bonds to create a new, curly shape. Relaxers work similarly but to straighten the hair.
• Keratin Treatments: These treatments use heat to infuse a liquid keratin formula into the hair, smoothing the cuticle and reducing frizz.