HairKnowHow Media Centre
Why You Should Stop Brushing Your Hair When Wet!
OK, lets talk about what physical changes occur in your hair when it comes in contact with water
Firstly, you need to know that hair is a hydroscopic material meaning that water does not just sit on its surface but is readily absorbed by it with as much as 75% of the maximum amount of water being absorbed within 4 minutes. This results in a number physical changes to your hair. The first is its change in the weight which can increase by as much as 20% (when going from a dry to a fully wetted situation). This added weight can contribute significantly to increase strain placed on your hair, especially during vigorous washing and especially brushing when wet.
Interesting enough as hair absorbs water it also swells anisotropically, which is a fancy word meaning that fibre swelling is not uniform for example the diameter each hair fibres can increase by as much as 16%, with the length increasing by only 2%. Now the majority of the swelling occurs due to water localising within the hair’s cortex (found in the centre of each hair fibre), but due to its fibrous nature the cortex can flex and respond well without physical damage.
The cuticle which is found on the surface each hair fibre is largely inflexible and brittle. The swelling of the cortex has been shown to result in a large number of the scales that make up the cuticle being lifted, especially at the margins, making them stick out, and more susceptible to chipping and fracturing, essentially reducing the lifetime of the cuticle layer. This type of damage is especially problematic when hair is brushed, pulled about or otherwise physically manipulated for example resulting in fibre-to-fibre abrasion. The health of the cuticle is highly related to the health and lustre of your hair and so should be cared for.
Another physical change that occurs during wetting is that hair becomes ‘stickier’ and tends to clump together as many of us would have noticed. This is especially notable using either water or shampoo only. This stickiness results in our hair being much harder to get a brush through requiring more physical effort. This increased ‘effort’ and pulling of the hair increases the likely hood of the hair being fatigued with increased breakage, something we will discuss more in a moment.
The vulnerability of hair to water is because all these physical changes combine during wetting, so extra care should be taken when physically manipulating hair in anyway when wet. Try to not pull it around too much, and for example during washing, message and support it as much as you can, and if you want to breakup knots and tangles await until you have applied conditioner to your hair and use your fingers to tease them apart or ideally wait until it is dry.
OK now we are going to take a bit more of a deeper dive into what physical and chemical changes occur to your hair during wetting, their impacts, and comparisons to dry hair.
It is important to know that the vast majority of the mechanical strength and elastic properties of your hair fibres come from the hair’s cortex. The cortex is where most of the Keratin strands are located, which are in turn stabilised by two types of molecular bonds: 1). Covalent bonds (namely the disulphide bonds) and 2). The hydrogen bonds.
The Disulphide bonds are very stable (intermolecular bonds) because the electrons of the two interacting sulphur atoms are being shared, and their high relative abundance within hair is why it is so persistent, potentially able to be last thousands of years within certain environments. An interesting example being the discovery in ancient Egypt of some mummies and their wigs still with hair intact! Which is pretty amazing! Importantly, in our water-hair story Di-sulphide bonds or covalent bonds in general are not easily disturbed or broken by water, and so are not largely affected by it.
Now Hydrogen bonds are the most important bonds when it comes to the story of water and hair. On their own, hydrogen bonds are relatively weak (approximately 9-32X weaker than disulphide bonds). However, they are far more numerous than disulphide bonds, given that oxygen, nitrogen, and hydrogen are some of the most abundant atoms within proteins, and so they contribute a substantial amount of ‘binding’ energy within hair. They make hair stronger increase flexibility and are importantly responsible for absorbing the majority of the longitudinal stress during the elastic response phase of hair. This is the kind of physical stress hair experiences when brushing or when it is pulled about! The Hydrogen bonds act to stabilise the keratin polymers relative to each other within the cortex, a bit like the individual strands of twine that interact via friction that together go to make up a rope.
The range hydrogen bond energies arise due to different atoms arrangements and their combinations of electronegative atoms that form the hydrogen bond. Two examples of electronegative atoms common in biology are oxygen and nitrogen. Hydrogen bonds do not result from the interacting partners sharing electrons but from interactions arising from differences in the local charges on the amino acid side chain, analogous to the different poles of magnets interacting, for example electronegative nitrogen will associate or hydrogen bond with a slightly positively charged Hydrogen atom nearby, forming a ‘Hydrogen bond’, this type of bond is also called a dipole interaction. (O-H, N-H, with an associated hydrogen atom will bind to either a neighbouring O or N within about 3 angstroms)
When hair is unwetted and dry, essentially its hydrogen bond network is intact, and your hair fibres are as strong as they are ever going to be.
Now this is where water come in. Hydrogen bonds are easily disturbed, weakened, or broken by water. This is because although hydrogen bonds form readily between the oxygen or nitrogen atoms with hydrogen they will typically bond with the strongest local polar molecule available, with the hydrogen-oxygen of water (H20) being typically more favoured over weaker nitrogen-hydrogen bonds that typically exist between the keratin polymers of the cortex. When the O-H of water displaces one of the interacting partners within the keratin polymer it effectively removes a hydrogen bond weakening the hair fibre.
When water enters your hair fibres this bond breaking occurs throughout each individual hair fibre and effectively reduces the numbers of ‘hydrogen bonds’ this directly impacting its strength and elasticity. Remember 75% change will typically occur within about 4 minutes of your hair getting wet. Laboratory results have shown large decreases in breaking strain by as much as 35% when comparing dry hair vs wet hair, and this weakening is significant.
These decreases in the strength and elasticity of hair have been seen not only in wet hair, but also within environments with increased humidly, with decreases in hair strength and elasticity correlating well with increasing humidity. Interesting fact! This breaking and reforming of bonds is the reason we can on a limited basis temporarily restyle our hair using only water!
Now another perhaps unseen effect of wetted hair is the large reduction in the amount of force required to overcome its ability to respond elastically to stress (elastic stretching is similar to an what we see with an elastic band stretching when we impart a force upon it with it returning back to its original length with no permanent damage).
We are talking about the kind of physical stress hair is subjected to when washing, where it gets pulled around or caught up when we run our fingers through it, or brush it when wet, things like that.
Once hair have been stretched past its elastic point it results in it becoming permanently plastically deformed, stretched, and fatigued. Within the lab this plastic deformation when wet has been observed resulting in the fibres becoming as much as twice their original length! This fatigued hair is considerably weaker, but also its stretching results in the uplifting or displacing of cuticle cells or scales which led to increased cuticle loss. This type of damage is not reversable and accumulative and so builds up over time. So, take extra care when manipulating your hair when wet, especially in the shower, bath or if you are in a high humidity environment.
This may all sound a little downbeat but remember that that once water has been removed from within your hair fibres, the hydrogen bond network is restored, so this temporary weakening is by definition reversed. If possible, try to brush your hair when dry, as it will be much stronger, require less effort and reduce damage to your hair’s beautiful cuticles. A little bonus tip for you to help reduce the impact of water on your hair, hair oils can be a great help, such as coconut and Argan oil, (these absorb into your hair which helps keep water out!) check out our website Hairknowhow.com to find out more.
What Is Chlorine Doing To Your Hair!
Today we are going to discuss what happens to your hair when you go swimming in a pool containing chlorine. We have had a couple of requests for this video from you our viewers, so thank you for that. Ok, so many of us would have heard horror stories about using either public or private swimming pools containing chlorine affecting hair colour, with some choice examples. We’ve heard of people’s hair ‘going green’ something hair professionals call chlorotrichosis, and of their hair being damaged by the chlorine in some way. These observations are specially focused on those that have natural blond hair and those who have recently dyed their hair. In this short for video, we will discuss this phenomenon, the science behind it, and even whether it is a ‘real’ thing or not. We will of course also be giving you tips on avoiding this happening to you, and how to fix your hair if it does change colour! So, enjoy!
Firstly, if you are a natural blond or have recently dyed your hair, your hairs colour can be affected when you get into a chlorine treated swimming pool, but possibly not for the reason you may think.
Let’s quickly talk about chlorine. Chlorine (or Free Available Chlorine) is used in swimming pools for several good reasons. Firstly, chlorine helps kill harmful bacteria and fungi that may start growing within swimming pools if given enough time. Free chlorine can be administered into pools using several different chemistries, which have different pool cleaning benefits, for example. Calcium hypochlorite and lithium hypochlorite are quite commonly used. Whichever, product is used a reaction occurs when they are added to water creating hypochlorous acid which exists in equilibrium with its ionic hypochlorite form. It’s this hypochlorous acid that’s referred colloquially as free chlorine, that we are interested in. Now swimming pool water can get quite dirty over time and it is important for the health of the swimmers that chlorine is used to keep the water clean, preventing bacterial and fungal growth, we do like our swimming pools nice and clean!
Remember, and this is a little unpleasant fact, but you are constantly shedding skin and other dirt particles, and these are especially likely to detach when swimming and seed the swimming pools water which can be good for bacteria and fungi. Of course, pool water contamination can come from elsewhere like, falling out of the air, or was even present in the water from where it travelled through your water pipes. Now often there is a filter to take away large particles and floating debris, but these do little to remove bacteria and fungi, which in some cases can make you sick or at best make the water green yukky and very slippery. Hence the need to treat the water, and chlorine is the choice chemical which is most widely used. It does a good job at keeping at keeping the bacteria and fungi at bay at relatively low concentrations, whilst doing little harm to people when used safely, other than being slightly smelly.
OK so now we know we must use chlorine but what is it and what does it do to your hair? Chlorine is an oxidiser, meaning that it can accept electrons from an interacting partner, chlorine is not special in this regard and other molecules that able to do this which includes reactive oxygen species, UV rays from the sun and hydrogen peroxide. Hydrogen peroxide you may already know is used to eliminate the natural or artificial colour pigments found within your hair during hair dyeing processes.
It is true that chorine does in fact penetrate your hair fibres cortex and reduce the amount of pigment present, now this effect is subtle but real and of course the greater your exposure to chlorine the lighter the colour your hair will become. Another important fact that we covered in our video on hair colour is that hair of different natural colours possesses different amounts of total melanin, and as the data shows its people that possess beautiful natural blond hair, and it goes without saying those who have coloured there will have less total melanin too. For natural blonds lower total hair melanin is entirely normal, and actually the reason their hair is blond in the first place, and it is a trait that tends to run in families (i.e. it’s an inherited trait). Right, now we’ll continue to talk about this in a moment.
Now hair possess a strong net negative charge at neutral pH (pH 7) due to it having a relatively low isoelectric point of pH 3.7 and so attracts molecules and ions that have net positive charge, similar to what occurs with magnets, where opposite polarities attract.
Of interest here is the fact that all metal ions including copper are positively charged. These metal ions are commonly found in water that has been stored in a metal containers, been in contact with brass fittings (like loft space tank), passed through copper pies or been, through a number of steel pipes to reach in this case the swimming pools we all use. Copper was and still is very commonly in homes and is used to move both water and natural gas about.
Now the amount of metal ions will depend on where you live, quality of the water, lots of things. These ions not only stick to your hairs surface but can under some circumstances diffuse into the cortex where they can accumulate (we’ll get to this in a moment). Now, in the vast majority of the cases you would never know these metal ions where present within your hair, because their affects cannot normally be seen and so go unnoticed.
However, what has also been observed is that in those people that have damaged hair, and what I mean by this that they have lost the majority or all their fibre’s cuticle, this loss their hair much more vulnerable to metal ion ingress, and this has been detected in the case of copper using lab instruments. For example, on study found a patient with green hair had 4 time more copper present in her hair relative to normal levels.
This is because the cuticle serves the critical function of protecting the underlying cortex from both physical and chemical attack, and in this case the cuticle helps prevent metal ions passing from the environment (your swimming pool) into your cortex.
Taken together the circumstances that need to combine that result in your hair seemly slowly or spontaneously changing green or any other colour are relatively rare. All of the following needs to be true 1). natural blond or have dyed your hair, 2). Have a significant cuticle damage, and 3). Live in an geographical area or within a house with increased metal ions (like copper) within the water.
Chlorine can play a role in making your hair more susceptible to this type of unexpected and unwanted colour change (green for example), but it does this by reducing the total melanin within your hair.
The elephant in the room is water, and it’s not just because water acts as a carrier or solvent for chlorine or these troublesome metal ions. Water damage, known as hygral fatigue (something we covered in a previous video) can be combined with increased fibre to fibre abrasive damage when swimming due to the swimmer’s movements. This has been seen in some studies of professional swimmers showing increased cuticle damage which can and has been proven to build-up.
So, what can you do about this? You should definitely not stop swimming; swimming is good for the mind and the body. The solution, for those of you that believe you have damaged cuticle or reduced melanin is quite simple really. Wear a swimming cap or hat. These do a good job of keeping the water and the chlorine off your hair plus minimises your fibres a braising against each other. If you don’t have a swimming cap to hand, then what you can do it prewet your hair in clean unchlorinated water. This will slow down the rate of chorine penetration into your hair whilst swimming.
If you find that you have suddenly developed green hair, it can be a surprise but try not to worry it can be corrected using commercial hair decolourisers which are commonly available, from salons or hair Highstreet shops.
Ok, so well done for making it to the end of our video. I hope you found it interesting and useful and learned a little about what happens to your hair when you go swimming, and the role chlorine plays in changing your hairs colour.
Help! Is my hair falling out?
Hi everyone, there is something quite scary about taking a shower and as you run our fingers through your hair you realise that there is a mass of it in your hand or as you set it to the side during shampooing and especially conditioning it strikes you that there is a lot of hair piling up on the side.
Its normal to worry and question as to whether your hair is all falling out and for it to be on your mind. But don’t worry. We will discuss hair shedding with examples and explanations as to why in the last majority of cases there is no need to worry. Also, in preparation for this video we collected a number of hair samples when conditioning during the shower (which did look like a lot at times) to show you. So, sit back and enjoy!
Right before we start, you need to know that losing a certain amount of hair throughout each day is entirely normal. It is all part of the hair cycle with older hair fibres falling out normally and being replaced by a new hair fibre that grows in place of the old one. This is constantly happening at low levels on your scalp in random locations so that there are no visible patches. Now before we start talking about how much hair we are losing per day there are some things we need to know first…
Hair grows out of the skin from small skin organs called follicles. The Follicle is the only part of hair that is considered alive, and they are responsible for synthesising our hair. Hair fibres are grown in repeating cycles that can last as long as 13 years. Each cycle can be broken down into four main phases, anagen, catagen, telogen and Exogen. Exogen ‘the fibre shedding stage’ is its own distinct phase but appears to be imbedded within telogen. These main phases can be further subdivided but for the purposes of this video we will stick with the main phases of the cycle.
But in short hair grows out of the follicle during is the anagen phase which lasts for between 2-7 years, the hair fibre then stops growing after this time and forms what is termed ‘hair club’ which results in the termination of the fibre whilst it is still within the follicle making it ready to shed. Club hair is formed during the transitional catagen phase that lasts only a short time of about 3 weeks. Next is the telogen phase where the follicle prepares for the synthesis of the next anagen fibre but also within the telogen phase is exogen which is where the previously produced anagen fibre now containing the club hair detaches. This duel or double phase lasts approximately 3 months. The Exogen phase is a relatively newly discovered phase revealed by research work carried out by Milner in 2002. This detachment phase is now known to be an active process that is caused by distinct changes within the follicle resulting in relatively weak fibre anchoring and its subsequent detachment. This is like what occurs when children lose their baby teeth. Whereby the adult teeth push the milk teeth out (its different but similar in appearance in some ways). At the end of the telogen-exogen phase the follicle enters the next anagen phase and a new hair fibre is produced starting the cycle again. We will create more in-depth video on hair growth cycle including looking at how the follicle changes morphologically -this is fancy way of saying that how it changes structurally so subscribe to ensure you don’t miss out.
Interestingly, the maximum possible length of our hair is mostly governed by the amount of time the hair follicle remains within the Anagen part of the follicle cycle, and this can and does vary due to both the environment and of course our genetics – thanks mum and dad!
Now, we are going to quickly go over some numbers, don’t be put off and hopefully this will make sense! Ok, at any one time if we were to determine what proportion of our hair was in each phase, we would find on average that approximately 1% of our follicles are in the catagen phase, 6-10% are in the Telogen-exogen phase with the remaining approximate 90-95% of hair follicles being in the anagen phase.
This has been shown experimentally following the careful study of many people’s scalps. In one of our previous videos, we discussed some of the differences in our hair colour, and we discovered that hair colour has a strong relationship to the number of hair follicles we possess. On average it has been determined that people have approximately 150 to 200 follicles per cm2 on our scalp, -yes scientists have counted! which equates to about 110,000 follicles in total.
A little fact for you: hair grows at a rate of about 400 microns (half a mm) per day, and that there is some scientific evidence that grey hair grows a little faster than pigmented hair (0.38mm for pigmented vs 0.35mm per day).
An interesting sidenote for you, when doing research for this video we came across many websites claiming that the average number of hair follicles correlated with hair colour but we couldn’t find any academic literature to back this claim up, (i.e. that red head have less hair per cm/2 than for example blonds or brunettes etc) actually the research papers we found said there was not statistical difference between hair colour and hair density.
Our challenge to you is if you can find a genuine original peer reviewed research paper on the relationship between hair density and hair colour, please link it below in the comments and the first person to post will win a free Hairknowhow hair test. If you don’t have any luck finding this out but find something interesting post it so we can all learn together. Happy researching😊.
OK, back to the numbers so what have we got so far, we have learned that we have about 110,000 follicles on our scalps and at any one time between 6-10% of them are in the telogen/exogen phase.
Remember it is within the telogen phase (in exogen) that we tend to naturally shed hair fibres, and this works out to number about 6,600 to 11,000 follicles. Now this doesn’t mean that we lose up to 11,000 fibres in one day, this does not happen, as only a very small fraction of our follicles shed fibres at any one time.
This is because of two main factors 1). essentially the chance of fibre detachment is mostly spread out over the duration of the telogen-exogen phase and 2). because each and every follicle is independent from each other from a cycling perspective, so as some follicles are entering telogen-exogen others will be exiting and many more will be actively growing in anagen etc.
If we take the number of hair fibres within telogen-exogen and divide this by the average duration of the phase (which is about 90 days), this results in an approximate calculated (back of the envelop) loss or drop rate of between 73 and 122 per day.
Within the scientific literature it is reported to be between 50 -150 fibres per day, so our calculated estimate is about right. Isn’t maths great! 150 fibres may sound a lot but remember you have approximately 110,000 on our scalps do as a proportion, it’s not many. For some context, this works out to be 0.13% at the maximum, which is not a lot.
So, what does this look like? We promised you some examples of the amount of hair that we found in whilst taking a shower. Now it looks like a lot of hair and as a rule of thumb the longer your hair the greater it will look. But also, its worth also considering that the amount of hair you collect in the shower is subject to many variables, and these are worth thinking about:
The longer the gap in-between showering the more hair you will collect. This is because not every hair fibre that detaches from the cuticle spontaneously blows away in the wind or collects on your pillow for example. Many of it will become caught up in your hair. So that when you wash and condition it, it can appear that you are holding a lot of hair that you think has detached in one go, but in truth it could be a few days’ worth – depending on the frequency you wash your hair. One variable that can decrease the amount of hair collected, is the amount of vigorous exercise you do, for example if you run a lot outside more of those naturally and already detached fibres will be lost and so less will appear in the shower, the same could be said for activities like swimming. Remember, fibre detachment is not increasing with exercise, but only more hair is being lost if you like.
This the end of our short video on this topic, we hope this has gone someway by both showing you examples and calculating the fibre drop rate that in the vast majority of cases when finding a little hair in your hand during the shower or on your pillow etc there is nothing to worry about when seeing hair. Of course, if you worried about increased hair loss, we recommend that you visit your GP or local expert hair clinic for advice.
Where Does Hair Gets It’s Natural Colour and Shine?
Where does hair get its natural colour and shine from? Today we are going to be discussing what components of your hair are responsible for producing its vibrant colour and its glossy shine, how best to look after your natural colour and look at how colour damage can occur. There will be a good amount of science included, so sit back and enjoy! Knowing a little about your hair is one of the first steps in being able to make informed hair health, product, and treatment choices. Let’s get into it!!
Hair naturally comes in many different colours, and the natural colour of your hair is mostly determined by your genes. Genes are the inheritable instructions found within DNA that is located inside the nucleus of most of the cells in your body. There is a very strong relationship between your ancestry and the colour of your hair. For example, red hair is more common in northern and western Europe typically northern England, Scotland and Ireland,
darker hair is more common as you enter central and southern Europe for example in France, Spain, Italy, and Turkey. But also, as you move east in Europe there is a relative increase in the occurrence of blond hair especially in Scandinavia. For more information and maps I’ll leave a link in the description check it out its pretty interesting.
Generally speaking, people with ethnic origins in central Asia, Africa and the far east have dark-brown hair or black coloured hair. This is a general/average view, and as with everything there are some exceptions. Why there are these differences in hair colour at all, or why lighter hair colours are more represented in higher latitudes is subject to scientific debate but may have something to do with both lower melanin production or expression coupled with the lower amounts of solar UV exposure experienced at higher latitudes.
Red hair colour is the rarest hair colour to be found and account for between 1 to 2 percent of the total population. It is rare because to have red hair required a double recessive genetic trait. Blond hair makes up around 2%, brown is 20% and black hair is the most common hair colour with approximately 75% of people worldwide possessing the colour.
Now this is where we get a bit sciency, we are going to talk about colour and colour perception. The colour of our hair or any other object that we visually observe is a relatively complicated subject and depends on a number of important factors:
1). The source of light being used, this is important as the amount of light (its brightness), and its light constituents (for example how blue or red a light source is) can affect the apparent colour of the object. Interestingly, you may have noticed that in very low light objects appear black and white and possess no colour.
This is because of the two types of light sensors in our eyes; the cone shaped photo receptors cannot detect colour in low light, and so we can only see in black and white curtesy of our more sensitive rod-shaped photo detectors.
2). The amount and wavelength of light the object absorbs or reflects, i.e. if hair absorbs all of the colours it will appear black in colour, if it absorbs all visible wavelengths but reflects red light it will appear red to us.
3). The surface texture and refractive index of the hair or object. These parameters affect how much light will be reflected and at what angle, which broadens the reflected light affecting the apparent shine or gloss.
4). Increased fibre porosity of the cortex has been shown to affect the gloss.
5). The sensitivity of the observer’s eye to the different colour or wavelengths its receiving.
6). Ability of the brain to process the data from the eyes to simulate or recreate the perception of the colour observed.
So, we can see that light and colour perception is a bit complex. For the rest of this video, we will take a deeper look at hair specifically in relation to colour.
There are two main components found within hair that together give rise to the natural colour variation that we observe. These two components are the cuticle which is mostly responsible for the glossy / reflective component of the colour this is found on the outer most part of your hair and then there is the cortex that contains granules or packets of pigment called melanin this is found within the interior of your hair for more details about the structure of hair please check out one of our previous videos.
Within the cortex there are two spectral variants of melanin pigments:
1). There is eumelanin, this is the most abundant pigment found in hair and is brown-to-black in colour
2). Pheomelanin is yellow-to-reddish in colour and is considered somewhat secondary and underlying given it is present at much lower levels to eumelanin. The vast majority of the diversity of hair colour arises due to both the total amount of melanin present within hair, and the ratio of eumelanin to pheomelanin. We have included a link in the description to the research containing this data, check it out it’s well worth a read.
So, looking at the amount of pheomelanin (seen in orange in the graph) its concentration in hair is fairly constant and present at a low level within those with black hair, brown and blond hair. The difference between these hair colours being the decreasing amount of Eumelanin. It’s worth noting that with decreasing Eumelanin but fixed pheomelanin the ratio between the two is changing and remember the ratio of these two pigments is also thought to be important in hair colour. In some cases, giving rise to the reddish-brown hues in some individuals were the ratio of Eumelanin to pheomelanin approaches 2:1 for example. So, if you’ve ever noticed that your friend has little red in their hair now you know why!
It appears that with red coloured hair, as Eumelanin decreases it allows for the secondary colour pigment pheomelanin to become more visible, this is somewhat similar to what happens in autumn when the green pigments with tree leaf’s breakdown revealing the beautiful reds and orange colours that were always present but not visible.
Interestingly, within red hair fibres there is a notable increase in the amount of the pheomelanin. It has been found that within red hair fibres the concentration of eumelanin is equal to the amount of pheomelanin giving an approximate ratio of 1:1 of the two melanin’s within the fibres. Recall that pheomelanin is reddish-yellow in colour. The two pigments together at an equal ratio give rise to the red colour we observe in red hair.
Blond hair typically contains the least amount of eumelanin of the different hair colours. This is why it is the lightest of the colours but unlike red hair those with blond hair does not have increased levels of pheomelanin giving a reddish-orange tint, so it is thought that blond hair colour arises mostly due to the low levels of eumelanin and total melanin within the fibres.
So, to recap the richness and colour depth or tone is governed by the total amount of melanin present within your fibres, so the greater the total amount of melanin present within your fibres the darker and potentially richer your tone, with less melanin giving you a lighter colour tone.
Something to be aware of is that recent epidemiological studies have shown a correlation meaning a relationship between decreased amounts of melanin found within your hair and increased risk of skin cancer, this is because the same genes and gene regulators make both hair and skin melanin, it was therefore shown that those with both red haired and blond hair people are at greater risk of developing skin cancer. So, if you have natural blond or red hair then cover your skin and hair or use good sunscreen to be on the save side.
Let’s move onto talking about the influence of the cuticle specifically on the gloss, reflective or lustre effect of your hair. The cuticle layer is made of overlapping cuticle cells a bit like the tiles on the roof of a house.
Now these cuticle cells are transparent to visible light but like many materials that are transparent they also reflect a proportion of the light too. There are two main types of reflection that we are going to talk about, there is specular reflection, this is the type of reflection that you observe with looking at a smooth surface like those of pools of water, from glass or a newly washed car, they are appear very bright reflections.
The other type of reflection is called diffuse reflection, this type of reflection results from surfaces that are rough. So going back to the cuticle layer. Healthy cuticles tend to be mostly flat, flush, and organised along the hair fibre, there is some texture to them, but typically very little.
This results in a good amount of specular reflection giving the appearance of glossy, lustrous, vibrant, and bright looking hair.
Unhealthy cuticle layer tends to be very disordered, uneven with bits of cuticle cells sticking out, or if the cuticle layer is lost altogether this exposes the cortex that is also very rough in appearance. Either way this creates essentially a rough surface for light to interact with, which diffuses the light sending it in all directions giving the appearance of dull or lack-lustre hair to the observer. So generally, healthier hair will have a glossier more lustrous appearance, however there are ways of cheating if your hair has cuticle damage or you want an even shiner to look, and that is by using coatings. Hair surface coating can take the form of oil or polymer coatings i.e. Silicones, these are common in conditioners, sprays and numerous treatment types.
To look after the colour of your hair, you need to take care of your hair’s cuticles and cortex. This way you preserve the beautiful intensity of your natural colour along with its shine.
The kinds of treatments we are talking about include regular conditioning, with a good conditioner, ideally one that contains oils shown to penetrate your fibres with positive health impacts, i.e. coconut and argan oil. Treat your hair with weekly deep conditioning treatments.
Cover up if you are out and about in intense sun light, like during the height of summer, try avoiding many of the typical chemical treatments we subject our hair too such as chemical colouring, straightening and heat treats were possible.
Both excessive sun exposure and these chemistries subject your hair to oxidative stress that breaks down your colour pigments, and as with the typical dyeing and straightening chemistries greatly disrupt your hair cuticle and cortex. Hence these are best avoided.
This was our introduction to the origins hair colour and how to look after it. I hope you found it interesting and useful.
The main structures found in hair
Do you know what gives your hair its strength, colour, and ability to resist all the rigors of day-to-day life? Today we are going to be talking the main structures found within your hair fibres and the roles they play in keeping your hair healthy and looking vibrant. Knowing a little about your hair is one of the first steps in being able to make informed hair health, product, and treatment choices. We believe that people happier when they informed about their hair and know how their haircare products and grooming routines are affect their hair.
As with many everyday objects with our hair we only see what our eyes allow us to see, that being at the relatively large scale of mm and cm. Without the aid of powerful microscopes, you would be forgiven for thinking that your hair is a bit like string or cotton, and that it was just a fibrous, floppy material that’s pretty tough and just happens to grow on your head.
However, using modern scientific tools we can see that hair is far more complicated and as with many things in nature, the closer you look the more detail is revealed and more beautiful they become.
Hair fibres have a conserved structure to them, meaning that all mammals possess the same macro structural characteristics.
Starting on the outside and working in there is the cuticle layer, which acts as a protective covering for the rest of the fibre, I think they look a bit like a stack of ice cream cones one on top of the other.
The cortex which as the name suggests is found in the centre of each hair fibre, this structure is responsible for many of the characteristics of hair for example: its where the vast majority of the hair fibres mechanical strength arises from and is also the place where the small packets of pigment (eumelanin and pheomelanin) responsible for the bulk of our hairs colour reside. Other rolls of the cortex include maintaining the overall shape and thickness of each fibre giving rise to the different hair types we observe.
There is a third structure sometimes found within the centre of the cortex of thick hair fibres called the medulla. The medulla is an elongated amorphous (meaning it’s a little irregular, disordered, spongy structure that is patchy along the fibre if present at all) structure. The role of the medulla is not currently known, and it is not always present in humans. Some research has observed it to be larger in grey hair, but this may be coincidental given the small sample size, more research is clearly required here to get to the bottom the mystery. As such for the purposes of this video we will concentrate on discussing details about both the cortex and the cuticle as these are the most important macro structures to beware of within your hair.
As I side note: Which hair structure is the most important I hear you ask? The answer is the health of both the cortex and cuticle is vitally important. The cortex does all the heavy lifting within the fibre but is vulnerable to environmental impact factors, like water ingress, UV exposure, chemical and mechanical damage. When we talk about hair nutrition and hydration, we are often talking about looking after the cortex’s well bring.
The cuticle serves to protect the cortex from as much damage as possible. Indeed, the primary mark of healthy hair is the health of the cuticle. If the cuticle is healthy then it is highly likely that the underlying cortex is healthy too, and you’ll possess healthy vibrant, strong hair. If either structure is significantly damaged, then split ends and hair breakage increase.
The structure of the cortex
The cortex in a relatively complex structure that makes up almost 90% of our hair by weight. It consists of bundles of smaller molecules, that we call a hierarchy, meaning that a number of smaller molecules interact together to form a single larger element that can then interact with other elements, each getting larger in scale each time. In hair this starts with the protein keratin that we cannot directly see going up in scale until we see as a single hair fibre.
In essence the cortex is made of linear or straight amino acids that when connected together develop a slight twist (a bit like what occurs between the steps of a spiral staircase, so that when you have hundreds or thousands of these proteins connected, they develop a cork screw shape that called an alpha helix, similar to what people think of when they pictures DNA.
These protein alpha helixes interact with each other via their side chains giving rise to coils of coils (called tetramers), with up to 10 tetramers interacting and twisting about each other going on to form a single intermediate filament. Bundles of intermediate filament aggregate or group together to form higher-order elements called micro-fibrils which themselves form the base structural element of macro-fibrils which themselves bundle together to form the cortex of each hair fibre. By organising the internals of a hair fibre in this way makes it very strong, and resistant to physical or chemical injury, flexible with good elasticity properties.
At all scales, these components are stabilised by intermolecular forces, namely: the covalent bonds (di-sulphide bond), hydrogen bonds and Van Der Waals. The importance of these bonds and how hair products affect them will be covered in a later video.
The way the cortex is internally organised does make it very resistant to physical injury, but there are as with all thing’s, areas of vulnerability. Space within the tightly packed cortex is very limited which is why water ingress into hair can be so problematic. Water diffuses into hair easily (taking about 4 minutes to do so) this is regularly seen in the laboratory causing swelling of the fibre at all scales. This swelling can and does cause direct fibril breakage resulting in a weakening of hair over time as the intermediate filaments break, this is called hygral fatigue. This type of damage can be reduced by using specific oils, which both displace water internally within a fibre and help prevent its diffusion in the first place. Consumer products that interact strongly with the cortex include chemical straighteners, bleaches and dyes, the mechanisms of these interactions and the health implications of them will be discussed in a later video.
The structure of the cuticle
The cuticle is made up of a number of flattened overlapping cells that are arranged longitudinally along the fibre. This is very similar to the way roof tiles are arranged on the roof of a house. You may have noticed that it is easier to brush away from your scalp (root to tip) rather than the other way, this is why. Conversely, backcombing causes increased damage to the cuticle and should be avoided. Your hairs cuticle layer is approximately 6-8 cell layers thick and is transparent (meaning light passes straight through to the cortex – where the colour pigments are located). It is mostly responsible for the apparent shine or gloss of your hair through interactions with light similar to the behaviour of a glass windscreen of a car, in that it is both transparent to light but can appear shiny too.
The primary role of the cuticle is to protect the underlying cortex from both chemical and physical injury, including water (hygral damage) and abrasive day to day damage from grooming etc. As the cuticle is damaged parts of it are shed revealing the undamaged lower layers. Remember there are only as many as 8 layers of cuticle cells surrounding your individual fibres, and once they have broken away, they cannot be repaired. So be careful when brushing especially when your hair is wet, and condition and or oil thoroughly to help protect it.
Many products interact with and are deposited onto the cuticle and act in different ways by design. These include conditioners, hair sprays, mousses, and gels. For example: some products soften, lubricate, and neutralise static charges on the cuticle like conditioners which helps gives the appearance of ‘soft hair’ that is easier to control, and some leave a stiff residue on the cuticle surface for styling purpose. In a later video we will cover how conditioners, shampoo and styling products work on your hair.
This was our introduction to some of the important structures found within your hair fibres, what they are made of and the roles they play.