The structure of hair

Welcome to BACK2MYROOTS B2MR:             
Regular postings of fresh new topic's

                          Understanding hair structure:
To be a good hair colourist we have to know so much! understanding how the  hair structure works what role it plays is key to  successful colouring.
 In order to understand the dynamics of hair colour we need to look at the hair's inner structure and understand how it is affected and changed in the colour process.
 The Cuticle:
The protective outer layer of the hair shaft the Cuticle is made up of Translucent overlapping layers of keratin protein.

Each layer completely encompasses the hair shaft.
imagine a stack of paper cups that might give you a visual image of the Cuticle.
Just as you might be able to bend a stack of cups without pulling apart the structure of the hair has the same pliability.
The cuticle affords the hair about 25% of its strength.
When the Cuticle is healthy it will lie flat against the hair shaft light will reflect of the translucent layers allowing the hair to appear to shine.
When we perform a chemical service on the hair perming or colour the Cuticle has to be opened to allow any chemical process to penetrate into the cortex to do this one has to change the natural Ph of the hair to do this we have to use an alkaline.

In the past ammonia has been the main driver of this part of the colouring process but it has always been though to cause damage and tends to smell.
Recently most of the major hair colour companies have been promoting healthy all natural products personally i find this marketing misleading now the catch words are herbal, organic, natural, unfortunately the products now driving the colour are MEA and Denatured Alcohol are they any less drying and damaging to the cuticle ? you decide! they all serve to open the cuticle they are all an alkaline.  personally i would rather know the strength of the ammonia in a colour rather than work with an unknown many professional hair colours did have quite high levels of ammonia i can live with ).4% up to2%.
Many Colour companies have replaced having bees wax as a buffer in hair colour with oil and silicon,
naturally after any chemical service the the correct Ph level must be restored to close the cuticle and restore that natural looking sheen a chemical balancing product is good for this it will restore the hair back to a pH of around 5.5.

The Cortex:
The Cortex makes up the bulk of the hair shaft the Cortex is composed of Keratin protein and 19 Amino acids. Keratin is a natural fibrous protein cross linked by sulfur bonds in the cortex the inner structure of the hair is known as the helix. we also find covalent and ionic bonds these are also effected by chemical services.
keratin is another well marketed product it it's naturally in the hair then added to products it must be good most hair products that have Keratin in them have a source derived from animal, vegetable, or mineral, Keratin from these sources will only lie on the out side of the hair with over use can make the hair slightly brittle so given the cost restrictions most companies opt for the cheaper source although these can and will give the sheen and make the hair look healthy they do not penetrate through the cuticle layer of hair. { molecular size is to Big 500}   The only keratin able to penetrate into the hair has to be hydrolyzed human hair Keratin.{molecular weight 150-300 able to penetrate the hair}

Fact {Hair is 89%protein and 10% moisture} so the only keratin that really can help the hair on an internal level is sourced from human hair.
On right healthy shining highlighted hair with Multi tones:
The medulla:
The medulla is the inner layer or center of the hair shaft, it is made up of softer Keratin protein than in the cortex it could be best described as being like raw sponge part of the  Medulla function is linked to the bodies excretory system.
Understand the roles of the above layers is key to performing good chemical services on the hair.

                                http://www.back2myroots.co.uk/
 The Above facts are well worth having in your tool kit of knowledge when performing Chemical services on the Hair!