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Chemistry of Hair color Through my senior project I explored the components and reactions that go into oxidative hair colors on a molecular level. Through research, thesis writing, and my ted talk I found and acknowledged that specific molecular structures in oxidative hair colors do not actually make a large difference in the health of the hair, nor do they impact the longevity of the color. For my action project, I created a portfolio of multiple hair colors created on live canvases in the form of an Instagram page.
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Since I did my LINK internship during my junior year for the whole month of may, I have been completely set on going to cosmetology school once I graduate from high school. After my internship at a local salon, I continued to work for my mentor over the summer and into the fall, followed by a LINK 2.0 (senior) Internship this last semester. In February I was accepted into Paul Mitchell the School Denver and will be attending in the fall. I have always loved playing with hair and coloring my own, as well as cutting an styling friends and family's'. The color aspect has always captivated me more than anything else; it involves chemistry, geometry, biology, and art all things that I love and all in one place.
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TED TalkDiscussing molecular structures present in oxidative hair colors and explaining how one can maintain healthy hair and lasting color.
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Senior thesis paper
What specific molecular structures create the healthiest hair and the longest lasting oxidative and permanent hair color?
Abstract
Many women and men alike are getting their hair colored on a regular basis but seldom stop to think about what actually happens to their hair. With the hair industry growing more than rapidly than ever before everyone from professional stylists to soccer moms need to be educated on the correct ways to get the ideal color that lasts as long as it can while keeping the hair as healthy as possible. In the following paper, I present the specific reactants and outcomes of oxidative, also known as permanent, hair coloring processes. The pool of research to pull from on this topic is relatively shallow and resulted in a select few scientific journals on various chemical process on multiple hair types. In the existing research there is a consensus that oxidative processes on hair can cause significant damage. This damage, however, can be minimized by taking the proper precautions before, during, and after coloring. Ultimately, the integrity of the hair is conditional to the education level of both the stylist and the client.
Part I: Introduction
Today there are several ways people can change their look in order to express or give themselves a fresh start - by far, the most popular is dying one’s hair. If you have ever strayed from your natural hair color, you may have taken into account the potential damage your hair will endure. It is also safe to assume that you’ve asked your stylist, or even the internet, how to maintain your new look. As well as questioning the upkeep of this look, the question of what process just occurred atop your head to give you the haircolor of your choice arises. More often than not, clients and stylists in the hair industry do not actually know what reactions happen in their hair when a hair color is changed on a deeper level. Colorists are taught to abide by to state standards which glean over the reactions that occur in permanent hair colors. Stylists with a better understanding of the chemistry of hair color are able to make more conscious decisions about their work as well as to relay this information to their clientele. Knowing what reactions are going on within one's hair will ensure clients take the proper steps to increase the longevity of their hair color. The various molecular structures and reactions that occur in oxidative (permanent) hair colors, and in turn, the education of stylists and clients, are vital to the life of the dye job, as well as to the health of the hair.
Part II: Historical Context/Background KnowledgeThe Anatomy of Hair:
The anatomy of hair is key to the way it reacts with permanent hair colors. Each hair strand is comprised of three to four parts: the follicle, the shaft consisting of the cuticle, the cortex, and occasionally a medulla. The follicle is essentially the root of the hair, a bulb-like end within the scalp which anchors the hair strand to the head and creates a place where the cells come together to form the hair shaft.
Figure 1: Cross Section of the Hair Shaft.
The hair shaft stems from the follicle externally from the head. This shaft makes up the majority of each strand of hair and contains three layers, as seen in Figure 1. The outermost layer is called the cuticle. Cells overlap similar to shingles on a roof. This creates a sealed barrier against weathering and outside forces while also providing shape and structure to the strand. When the cuticle is laid flat and correctly, the hair appears very smooth and shiny which tells us about the health of the hair which, in this case, is good. An example of unhealthy hair, as many of us know, is frizzy, dry hair which occurs when the cuticle has been damaged (One, 1). This damage is most visible in the center layer of the shaft, known as the cortex. The cortex is the most dense and largest part of the shaft where pigments in the form of melanin are stored. This section is made of keratin which is Figure 2: Hair Shaft Layers. comprised of polypeptide chains that form amino acids. These chains are held together by relatively strong bonds that are broken through chemical coloring processes, more specifically, permanent hair coloring (Yang 1). Found in only select hair types, typically thicker, coarser hair, is the core-like center referred to as the medulla, seen in Figure 2. There is little information on the innermost layer of the hair shaft as it has yet to be explored in depth.
As previously mentioned, the cortex is the area where pigment is stored, making it,
arguably, the most important layer of the hair shaft Figure 3: The Tyrosine Molecule. when it comes to dye. Natural pigment is more widely known as melanin and presents itself as various colors in skin and hair and eyes, among other places. Melanin is comprised of proteins and is made from an amino acid called tyrosine; this mo
lecule can be referenced in Figure 3 to the right. “There are two types of melanin protein found in the hair: eumelanin, which is responsible for hair shades from black to brown, and pheomelanin, which is responsible for red and yellow-ish colors.” (Raber 1) Grey, white, and bleached hair are a result of little to no melanin being present in the cortex.
This melanin is present in the protein keratin which is found primarily in the cortex as well. Keratin occurs when the dead cells which make up the hair strand go through a process called keratinization once they emerge from the follicle (França et al 2). “Keratin is made up of polypeptide chains of amino acids such as glycine, alanine, and cysteine. The individual amino Figure 4: Keratin’s Structure. acids are held together by polypeptide bonds, and there are multiple other complex bonds involved.” (Unknown 1). These polypeptide chains form helices which then bind together to form cords which form proto-, micro- and macro-fibrils as seen in Figure 4. The bonds that hold polypeptide chains together can be broken only through chemical processes such as hair oxidative hair color.
Part III: Research and Analysis
Oxidative Hair Color Structure and Mechanism of Action:
Oxidative hair colors tend to be the most widely used because of their long lasting qualities as well as because they tend to be the most commonly known and used in salon settings due to the countless outcomes that can be achieved with these permanent hair colors. The terms oxidative and permanent are used interchangeably due to the process the hair undergoes when in contact with this type of dye. This process is an “oxidation reaction that allows the pigments to get inside the cortex” (Dias 3) of the hair where melanin is present. Through oxidizing the already present pigment, oxidative hair colors are the most permanent option and can only be grown out, not removed like their less invasive, non-oxidative counterparts. “Demi-permanent (non-oxidative) dyes do not contain ammonia or ethanolamine and for this reason are gentler on the hair than the permanent colors.” (Dias 3). Temporary hair colors do not have the important reactions that oxidative ones do. Theses reactions are key to a long lasting color and are the only way to make an artificial hair color have permanence.
The color forms through a reaction between oxidizing agents - such as hydrogen peroxide and sodium persulfate (commonly referred to as developer) - and bases which take place as soon as the substances are combined (França et al 10). Oxidizing agents borrow electrons from the bases, commonly NH2 and OH, which have electrons to easily transfer. Reaction modifiers come in various forms and are available but do not yield the same strength of color as the ladder base substitutes, nor do they promote easy oxidation.
Another important aspect to the correct color outcome through the reaction at hand is an alkalizing compound. The alkali softens the cuticle layer which allows the dye to penetrate into the cortex. A compound that is commonly used is “ammonia in the form of ammonium hydroxide” (França et al 12), which also explains the odor clients and stylists associate with hair coloring. Ammonia also plays a key role in lifting natural pigments from the hair. When pigments are removed from the hair they cannot be restored to their original state because the new colored polymer forms in the cortex in its place. This reactive trait is what deems the dye permanent, once the new polymers enter the hair, they are very resistant but can eventually make their way out over time.
The color molecules’ size is one of the largest factors in the life of a hair color. During the same hair coloring application the color polymers within the cortex can be expected to be of close size to each other otherwise the molecules will penetrate unevenly; in turn resulting in an uneven appearance and aging. These molecules “...are initially small in size and are then transformed into [a base molecule] with greater size than those that do not have a satisfactory penetration.” (França et al 15). These molecules are able to permeate and stay in the hair longest because they undergo this change once they are already in the hair.
Final hair color can be affected by many different factors throughout the processing. One of the biggest components in artificial hair color is the pH of the hair. “Anything between 0 and 6.9 is acidic, 7 is neutral, and anything between 7.1 and 14 is alkaline. Human hair and scalp oil, sebum, has a pH balance of between 4.5 and 5.5.” (Natural Girls Rock 1) A hair shaft with an alkaline, also referred to as basic, pH “favors the reaction and facilitates the cuticle opening, allowing the penetration of molecules into the cortex.” (França et al 14). On the other hand, a strand with a much more acidic or neutral pH results in a cuticle that resists opening and therefore, the color molecules are unable to penetrate even the outer layer, not to mention unable to penetrate into the cortex of the shaft.
Another important factor in the acceptance of color is the hair’s condition and health. Essentially, if a hair strand has already been lifted (oxidized) then the cuticle is opened and the natural pigments have been stripped from the cortex. In this case the hair appears less smooth than before oxidation, when the hair had it's natural pigments and was “virgin” as referred to in the industry. This appearance comes from the cuticle no longer laying flat. Lifted hair absorbs and responds to color better because of the welcoming, opened cuticle as well as the fact that there is no longer pigment in the cortex. The absence of melanin, offers much more space for the new color to fill in with ease similar to how a dry sponge absorbs water much easier than a wet sponge. With influences such as pH, hair condition and health, as well as various other factors taken into account, the proper hair color can better be selected as well as adapted for the hair type and condition in order to promote the healthiest hair and a hair color that endures the most.
Part IV: Discussion and Conclusions
It is important to be educated on the components of permanent hair colors and the reactions they undergo in order to make the best decision for the health of one's hair as well as the longevity of the hair color. With stylists being better educated on a molecular level of the reactions they create they can best account for the ending integrity of the hair based on things like the client’s hair type, condition, and color, among others. Hair stylists who practice professionally are licensed by the state but this isn’t to say that the client’s questions and recommendations are invalid. Of course more research can always be conducted on oxidative hair colors in particular as this subject has yet to be exhausted.
Ultimately, the responsibility falls on both the stylist and the client when it comes to changing hair color with oxidative hair dye. In the instance that a hair color is mixed and applied correctly, aftercare is still as necessity. Once the cuticle is disturbed it needs to be cared for in order to lay back smoothly and holdin the new pigment to its best. Measures that can be taken from home are things like shampooing rinsing with lukewarm to cool water and applying conditioning treatments or masks regularly. Both of these precautions ensure that the cuticle stays smooth and closed, keeping the color in and making the hair appear as healthy and undamaged as possible externally. Stylists need to take on the responsibility of being educators and informing their clients of these things as well as taking the proper precautions to create the best hair color. Ideally, hair stylists do what they do because they receive satisfaction from creating a healthy and presentable style over soley being salesfolk who neglect the importance of their job to society. They need to apply their licensure and remember to not do things that damage the hair such as overlapping oxidative colors or lighteners because this damages the hair shaft more than necessary. Selecting a developer which is stronger than needed can also cause unwarranted damage to the hair shaft because it works to lift the color which is no longer present, resulting in a shaft which is much drier than ideal. Being educated on the reactions that occur allows for the proper decisions to be made concerning the integrity of the hair.
As previously presented, there are multiple factors that impact the final color and health of the hair - many of which can easily be influenced by an outside source. Evaluating the health of the hair is the first step; has it ever been through chemical processes? Has the melanin been oxidized? What level is the melanin? Using a developer which creates a reaction too strong results in the hair being damaged to a level that it doesn’t need to be to yield the prefered appearance. Another example is the improper use of alkalizing agents. Ammonia is the main agent used in this type of reaction to keep the pH ideal, without it it could be too neutral, or in some cases, too acidic. This results in the cuticle staying closed which keeps the color from entering the cortex. Failing to acknowledge details like these results in the hair strand being more damaged than expected as well as the color not lasting to its full capacity.
This is a subject that has yet to be researched to large depths because there are so many different routes and rabbit holes to take. Only a select group takes interest in this subject and more often than not, colorists overlook the research and tests that have been performed. Ultimately, this information is not necessary to become a licensed cosmetologist, nor is it needed to maintain an occupation in the hair and cosmetics industry. It is, however, a tool which leads to being a successful stylist as well as one that encourages an aspect of education to the client and general public.
Further research should always be conducted, especially on aspects of the hair shaft other than the cortex. There is little research done on the medulla of the hair and how it is impacted by oxidation. Another area of further research is how oxidative hair color’s effects on the growth of new hair from the follicle differ from those of non-oxidative colors. A third area yet to be explored is the impact that hair colors have on the melanin in the scalp and other skin cells. Overall, this is a subject with plenty of room to grow and be explored as the hair industry is ever changing.
Many women and men alike are getting their hair colored on a regular basis but seldom stop to think about what actually happens to their hair. With the hair industry growing more than rapidly than ever before everyone from professional stylists to soccer moms need to be educated on the correct ways to get the ideal color that lasts as long as it can while keeping the hair as healthy as possible. In the following paper, I present the specific reactants and outcomes of oxidative, also known as permanent, hair coloring processes. The pool of research to pull from on this topic is relatively shallow and resulted in a select few scientific journals on various chemical process on multiple hair types. In the existing research there is a consensus that oxidative processes on hair can cause significant damage. This damage, however, can be minimized by taking the proper precautions before, during, and after coloring. Ultimately, the integrity of the hair is conditional to the education level of both the stylist and the client.
Part I: Introduction
Today there are several ways people can change their look in order to express or give themselves a fresh start - by far, the most popular is dying one’s hair. If you have ever strayed from your natural hair color, you may have taken into account the potential damage your hair will endure. It is also safe to assume that you’ve asked your stylist, or even the internet, how to maintain your new look. As well as questioning the upkeep of this look, the question of what process just occurred atop your head to give you the haircolor of your choice arises. More often than not, clients and stylists in the hair industry do not actually know what reactions happen in their hair when a hair color is changed on a deeper level. Colorists are taught to abide by to state standards which glean over the reactions that occur in permanent hair colors. Stylists with a better understanding of the chemistry of hair color are able to make more conscious decisions about their work as well as to relay this information to their clientele. Knowing what reactions are going on within one's hair will ensure clients take the proper steps to increase the longevity of their hair color. The various molecular structures and reactions that occur in oxidative (permanent) hair colors, and in turn, the education of stylists and clients, are vital to the life of the dye job, as well as to the health of the hair.
Part II: Historical Context/Background KnowledgeThe Anatomy of Hair:
The anatomy of hair is key to the way it reacts with permanent hair colors. Each hair strand is comprised of three to four parts: the follicle, the shaft consisting of the cuticle, the cortex, and occasionally a medulla. The follicle is essentially the root of the hair, a bulb-like end within the scalp which anchors the hair strand to the head and creates a place where the cells come together to form the hair shaft.
Figure 1: Cross Section of the Hair Shaft.
The hair shaft stems from the follicle externally from the head. This shaft makes up the majority of each strand of hair and contains three layers, as seen in Figure 1. The outermost layer is called the cuticle. Cells overlap similar to shingles on a roof. This creates a sealed barrier against weathering and outside forces while also providing shape and structure to the strand. When the cuticle is laid flat and correctly, the hair appears very smooth and shiny which tells us about the health of the hair which, in this case, is good. An example of unhealthy hair, as many of us know, is frizzy, dry hair which occurs when the cuticle has been damaged (One, 1). This damage is most visible in the center layer of the shaft, known as the cortex. The cortex is the most dense and largest part of the shaft where pigments in the form of melanin are stored. This section is made of keratin which is Figure 2: Hair Shaft Layers. comprised of polypeptide chains that form amino acids. These chains are held together by relatively strong bonds that are broken through chemical coloring processes, more specifically, permanent hair coloring (Yang 1). Found in only select hair types, typically thicker, coarser hair, is the core-like center referred to as the medulla, seen in Figure 2. There is little information on the innermost layer of the hair shaft as it has yet to be explored in depth.
As previously mentioned, the cortex is the area where pigment is stored, making it,
arguably, the most important layer of the hair shaft Figure 3: The Tyrosine Molecule. when it comes to dye. Natural pigment is more widely known as melanin and presents itself as various colors in skin and hair and eyes, among other places. Melanin is comprised of proteins and is made from an amino acid called tyrosine; this mo
lecule can be referenced in Figure 3 to the right. “There are two types of melanin protein found in the hair: eumelanin, which is responsible for hair shades from black to brown, and pheomelanin, which is responsible for red and yellow-ish colors.” (Raber 1) Grey, white, and bleached hair are a result of little to no melanin being present in the cortex.
This melanin is present in the protein keratin which is found primarily in the cortex as well. Keratin occurs when the dead cells which make up the hair strand go through a process called keratinization once they emerge from the follicle (França et al 2). “Keratin is made up of polypeptide chains of amino acids such as glycine, alanine, and cysteine. The individual amino Figure 4: Keratin’s Structure. acids are held together by polypeptide bonds, and there are multiple other complex bonds involved.” (Unknown 1). These polypeptide chains form helices which then bind together to form cords which form proto-, micro- and macro-fibrils as seen in Figure 4. The bonds that hold polypeptide chains together can be broken only through chemical processes such as hair oxidative hair color.
Part III: Research and Analysis
Oxidative Hair Color Structure and Mechanism of Action:
Oxidative hair colors tend to be the most widely used because of their long lasting qualities as well as because they tend to be the most commonly known and used in salon settings due to the countless outcomes that can be achieved with these permanent hair colors. The terms oxidative and permanent are used interchangeably due to the process the hair undergoes when in contact with this type of dye. This process is an “oxidation reaction that allows the pigments to get inside the cortex” (Dias 3) of the hair where melanin is present. Through oxidizing the already present pigment, oxidative hair colors are the most permanent option and can only be grown out, not removed like their less invasive, non-oxidative counterparts. “Demi-permanent (non-oxidative) dyes do not contain ammonia or ethanolamine and for this reason are gentler on the hair than the permanent colors.” (Dias 3). Temporary hair colors do not have the important reactions that oxidative ones do. Theses reactions are key to a long lasting color and are the only way to make an artificial hair color have permanence.
The color forms through a reaction between oxidizing agents - such as hydrogen peroxide and sodium persulfate (commonly referred to as developer) - and bases which take place as soon as the substances are combined (França et al 10). Oxidizing agents borrow electrons from the bases, commonly NH2 and OH, which have electrons to easily transfer. Reaction modifiers come in various forms and are available but do not yield the same strength of color as the ladder base substitutes, nor do they promote easy oxidation.
Another important aspect to the correct color outcome through the reaction at hand is an alkalizing compound. The alkali softens the cuticle layer which allows the dye to penetrate into the cortex. A compound that is commonly used is “ammonia in the form of ammonium hydroxide” (França et al 12), which also explains the odor clients and stylists associate with hair coloring. Ammonia also plays a key role in lifting natural pigments from the hair. When pigments are removed from the hair they cannot be restored to their original state because the new colored polymer forms in the cortex in its place. This reactive trait is what deems the dye permanent, once the new polymers enter the hair, they are very resistant but can eventually make their way out over time.
The color molecules’ size is one of the largest factors in the life of a hair color. During the same hair coloring application the color polymers within the cortex can be expected to be of close size to each other otherwise the molecules will penetrate unevenly; in turn resulting in an uneven appearance and aging. These molecules “...are initially small in size and are then transformed into [a base molecule] with greater size than those that do not have a satisfactory penetration.” (França et al 15). These molecules are able to permeate and stay in the hair longest because they undergo this change once they are already in the hair.
Final hair color can be affected by many different factors throughout the processing. One of the biggest components in artificial hair color is the pH of the hair. “Anything between 0 and 6.9 is acidic, 7 is neutral, and anything between 7.1 and 14 is alkaline. Human hair and scalp oil, sebum, has a pH balance of between 4.5 and 5.5.” (Natural Girls Rock 1) A hair shaft with an alkaline, also referred to as basic, pH “favors the reaction and facilitates the cuticle opening, allowing the penetration of molecules into the cortex.” (França et al 14). On the other hand, a strand with a much more acidic or neutral pH results in a cuticle that resists opening and therefore, the color molecules are unable to penetrate even the outer layer, not to mention unable to penetrate into the cortex of the shaft.
Another important factor in the acceptance of color is the hair’s condition and health. Essentially, if a hair strand has already been lifted (oxidized) then the cuticle is opened and the natural pigments have been stripped from the cortex. In this case the hair appears less smooth than before oxidation, when the hair had it's natural pigments and was “virgin” as referred to in the industry. This appearance comes from the cuticle no longer laying flat. Lifted hair absorbs and responds to color better because of the welcoming, opened cuticle as well as the fact that there is no longer pigment in the cortex. The absence of melanin, offers much more space for the new color to fill in with ease similar to how a dry sponge absorbs water much easier than a wet sponge. With influences such as pH, hair condition and health, as well as various other factors taken into account, the proper hair color can better be selected as well as adapted for the hair type and condition in order to promote the healthiest hair and a hair color that endures the most.
Part IV: Discussion and Conclusions
It is important to be educated on the components of permanent hair colors and the reactions they undergo in order to make the best decision for the health of one's hair as well as the longevity of the hair color. With stylists being better educated on a molecular level of the reactions they create they can best account for the ending integrity of the hair based on things like the client’s hair type, condition, and color, among others. Hair stylists who practice professionally are licensed by the state but this isn’t to say that the client’s questions and recommendations are invalid. Of course more research can always be conducted on oxidative hair colors in particular as this subject has yet to be exhausted.
Ultimately, the responsibility falls on both the stylist and the client when it comes to changing hair color with oxidative hair dye. In the instance that a hair color is mixed and applied correctly, aftercare is still as necessity. Once the cuticle is disturbed it needs to be cared for in order to lay back smoothly and holdin the new pigment to its best. Measures that can be taken from home are things like shampooing rinsing with lukewarm to cool water and applying conditioning treatments or masks regularly. Both of these precautions ensure that the cuticle stays smooth and closed, keeping the color in and making the hair appear as healthy and undamaged as possible externally. Stylists need to take on the responsibility of being educators and informing their clients of these things as well as taking the proper precautions to create the best hair color. Ideally, hair stylists do what they do because they receive satisfaction from creating a healthy and presentable style over soley being salesfolk who neglect the importance of their job to society. They need to apply their licensure and remember to not do things that damage the hair such as overlapping oxidative colors or lighteners because this damages the hair shaft more than necessary. Selecting a developer which is stronger than needed can also cause unwarranted damage to the hair shaft because it works to lift the color which is no longer present, resulting in a shaft which is much drier than ideal. Being educated on the reactions that occur allows for the proper decisions to be made concerning the integrity of the hair.
As previously presented, there are multiple factors that impact the final color and health of the hair - many of which can easily be influenced by an outside source. Evaluating the health of the hair is the first step; has it ever been through chemical processes? Has the melanin been oxidized? What level is the melanin? Using a developer which creates a reaction too strong results in the hair being damaged to a level that it doesn’t need to be to yield the prefered appearance. Another example is the improper use of alkalizing agents. Ammonia is the main agent used in this type of reaction to keep the pH ideal, without it it could be too neutral, or in some cases, too acidic. This results in the cuticle staying closed which keeps the color from entering the cortex. Failing to acknowledge details like these results in the hair strand being more damaged than expected as well as the color not lasting to its full capacity.
This is a subject that has yet to be researched to large depths because there are so many different routes and rabbit holes to take. Only a select group takes interest in this subject and more often than not, colorists overlook the research and tests that have been performed. Ultimately, this information is not necessary to become a licensed cosmetologist, nor is it needed to maintain an occupation in the hair and cosmetics industry. It is, however, a tool which leads to being a successful stylist as well as one that encourages an aspect of education to the client and general public.
Further research should always be conducted, especially on aspects of the hair shaft other than the cortex. There is little research done on the medulla of the hair and how it is impacted by oxidation. Another area of further research is how oxidative hair color’s effects on the growth of new hair from the follicle differ from those of non-oxidative colors. A third area yet to be explored is the impact that hair colors have on the melanin in the scalp and other skin cells. Overall, this is a subject with plenty of room to grow and be explored as the hair industry is ever changing.