If you want to know why your hair looks, feels and behaves the way it does, this post is for you. We’re going to get right to the root of hair, explaining what it is and how it’s structured, so you can understand the best way to keep it looking and feeling its best.
And for those times when you need a little extra help, we’ll show you how a treatment like Smartbond can really up your ‘good hair day’ count.
Let’s start with some simple biology…
What is hair, exactly?
Hair is made from keratin, part of a family of fibrous proteins. The long, tube-like shape that we recognise as a hair is actually a chain of proteins that grows from a follicle in the dermis of the skin.
Three main parts form the structure of each hair: the cuticle (the outer layer), the cortex (the middle layer) and the medulla (the inner core).
Under a microscope, the cuticle looks like the scales on a fish. Dead cells form overlapping layers that give each hair its outer strength and protect the bonds inside from stress or degradation.
The next layer is the cortex. This contains pigment, which gives your hair its colour. Similarly to the pigment in your skin, hair pigment contains melanin – with the important difference that its effect varies from person to person. For example, red pigment will appear denser on darker brown or black hair, but more yellow in blonde hair.
The inner layer, at the very centre, is the medulla. This is the most fragile and soft part of the hair. Its size varies from follicle to follicle, but here is where a large amount of your DNA is stored.
These three layers are securely held together by bonds that cross over each other to create a tightly packed infrastructure. The bonds are amino acids (known as cysteines) that are unique in their ability to form connections thanks to a sulphur base, which allows them to form strong connections with other sulphur molecules.
Why do we all have different ‘types’ of hair?
The keratin and bonds in your hair determine its texture and shape and give each hair around a third of its overall strength. There are three types of bond that link the protein chains together: disulphide bonds (which are strong); and hydrogen bonds and salt bonds (which are weaker).
The shape of each hair is determined by the amount of strong, disulphide bonds it contains, as well as the distribution of those bonds. The more evenly distributed the disulphide bonds, the straighter the hair – in which case, the follicle tends to be cylindrical in shape. Clustered and uneven distribution of disulphide bonds creates curlier hair with a flatter or oval-shaped follicle.
Is it possible to change the shape of hair?
Much as some of us would love it too, water alone won’t alter the shape of your hair; so if you want to achieve significant change you’ll need to expose your hair to a process that weakens the bonds.
Chemical interventions – such as perms and relaxers – break down the disulphide, thereby allowing the stylist to manipulate the shape of the hair. But, once a process like this is completed it’s impossible to reverse the effects of broken, reshaped bonds. Applying a second relaxing or perming service in order to restore the hair’s original shape inevitably leads to hair breakage and loss of elasticity.
It’s not only harsh chemicals that can alter your hair’s structure: heat styling, hair colouring, environmental UV and even brushing can damage the cuticle and allow the hair to become porous over time, thereby speeding up oxidisation and damaging those strong disulphide bonds.
Salt bonds and hydrogen bonds are found all over the cortex. Unlike disulphide bonds, which largely remain intact until a chemical process occurs, salt and hydrogen bonds break down when exposed to water or to pH levels above 5.5 (in the case of salt bonds, managing pH levels can stabilise them). It is these bonds that allow you, or your stylist, to change the shape of your hair temporarily.
You have probably noticed that, when exposed to water and heat, your hair can become more elastic and ‘stretchy’. This is because water and heat temporarily break down the salt and hydrogen bonds, making your hair easier to style by moulding it into shape when wet and setting it (re-bonding) by drying. Heat styling has a similar effect, whereby the heat breaks the bonds in order to create a style, which is set (re-bonded) when cooled.
What actually causes frizzy hair?
Frizzy hair occurs where humidity (water) affects the hydrogen bonds by breaking them down and altering the pH, and consequently the shape of each hair.
When the proteins (in this case, the hydrogen bonds) are exposed to water or heat, oxygen atoms attract the hydrogen atoms, charging the oxygen electrons negatively (known as ions). Ions don’t disappear – they stay where they are, building up more and more as the hair is exposed to increased oxidation, the breakdown of hydrogen and salt bonds, and the degradation of disulphide bonds. Long term, this results in loss of elasticity and hydration that can diminish shine and, ultimately, causes breakage.
How do we protect and repair broken hair bonds?
This is where Smartbond comes in. It’s a unique formula of maleic acid and ceramide polymers that work to repair the damage to both the strong disulphide bonds and the weaker hydrogen and salt bonds.
There are three steps to consider in the Smartbond process. The formula can be applied as a standalone treatment, or included as part of an oxidative service (for example colouring, when a developer is used):
The first step contains, predominantly, maleic acid. This rebalances the pH level of the hair and encases the disulphide bonds to strengthen them and repair any damage. It also works to prevent future damage by repairing the weak bonds of hydrogen and salt – a bit like putting on a raincoat to stop your clothes getting wet. Finally, step 1 removes any build-up of those negatively charged ions.
The second step also contains maleic acid (to continue balancing pH levels and removing any remaining ions) with the addition of ceramide polymers (a type of fatty acid) to help bind and close the cuticle layer. This makes the strands less porous and helps them retain moisture and elasticity for stronger, shinier, silkier hair overall.
If Smartbond is part of your colour treatment, this step also prevents colour loss. The formula can be added when your technician mixes your colour, to ensure that the ingredients continue to work when rinsing out, shampooing and conditioning.
Steps 1 and 2 can also be booked as a standalone service. In this case, Smartbond is applied on dry hair in our backwash area, where your Paul Edmonds London technician will carefully mix the correct amount and time the application to maximise the repair of the strong and weak bonds.
Ask your stylist for further information if you would like to add Smartbond into your next appointment or book it as a standalone treatment. The latter takes just 15 minutes and costs £35.
What happened to Step 3?!
As you continue to wash your hair, use heated styling tools and expose it to UV and oxidative stress over time, the ceramide polymers from the Smartbond will diminish.
Step 3 is a homecare product that you can purchase at Paul Edmonds London. Add it to your regular shampoo once or twice a week to keep the polymers, and your hair cuticle, in tip-top shape.
For more information about Smartbond and advice on how to keep your hair happy and healthy all winter long, get in touch with the hair and beauty experts at Paul Edmonds London.