Each hair shaft is made up of two to three layers – the cuticle, cortex and sometimes medulla. The cuticle is the outer layer, made up of flattened cells that overlap each other and form scales to protect the shaft. The cortex is the thickest layer and contains melanin which gives hair its colour and protects the inside of the hair shaft from damage.
A healthy hair cuticle when magnified is smooth, flat and retains moisture. Hair that is slightly damaged will have porous, open cuticles. The layers are lifted up and moisture escapes resulting in frizz and dryness. Hair that has undergone chemical processing, heat styling or hair colouring may be more damaged so the hair shaft is open and damaged. The scales of the cuticle layer are chipped away, cortex is exposed and hair is extremely porous. Hair is unable to retain moisture properly and breaks easily.
Common external stresses that lead to damaged hair:
⦁ harsh weather
⦁ frequent and rough brushing, friction from towel drying
⦁ bleaching, highlighting, chemical processing
⦁ swimming in chlorinated pools or salt water
⦁ long exposure under the sun
⦁ heat styling
The Importance of Proteins and Amino Acids in Hair Care
Proteins are large molecules made up of amino acids and need to be broken down (hydrolyzed) in order to be useful for hair care. Why do some products contain different types of hydrolyzed protein? That’s because not all proteins are created the same. They vary in molecular weights and function differently, some being more conditioning, while others work on strengthening the hair. So if there is more than one hydrolyzed protein listed in the label, it’s a good thing!
Low molecular weight proteins is substantive to hair. They can even penetrate into the damaged cortex and fill in the porous gaps, hence repairing and strengthening weakened hair. The larger proteins have more of a conditioning effect by coating the hair shaft and sealing moisture.
Free amino acids play an important role in hair too. The hair naturally has many amino acids in the cuticle that attract water to keep hair hydrated so it is not prone to breakage.
Proteins and amino acids lead to hydrated hair resulting in healthy shine, more elasticity and stronger, more manageable hair.
