Cindy Lei
Dying for a Hair Color Change
Abstract:
A person’s hair color is a self-expression of who they are. It represents their image, age,
culture, status, and personal taste. With today’s technology, people are able to change
their hair color as their connection and definition of one-self varies as time goes on. This
scientific break through has also lead to a global impact of safety concerns as chemical
compounds are involved in altering the biological aspect of hair phenotypes. A following
discussion is provided in examining the science behind hair dye ingredients.
Keywords: Hair, Color, Pigment, Chemicals, Hair Dyes, Safety, Hazards, and
Carcinogens
Multimedia Suggestion: http://www.youtube.com/watch?v=FHSmajz99UA
About me (short bio):
Cindy Lei is a University of Southern California undergraduate studying an emphasis
under chemical engineering in polymers and materials. During her free time, she enjoys
going out for a cup of bubble milk tea with friends and family and is currently learning
how to master the clarinet. In addition, she is also self-teaching herself how to make
jewelry as a hobby.
Introduction:
With an ever-aging population and a need for change, many people change their
hair color for a quick yet effective transformation in appearance and self-esteem. After
all, the hair is one of the first features most people notice as it’s connected to the skin and
face of the person your interacting with. Beyond that, the color of a person’s hair plays a
dominant role in attractive diversion by portraying a person’s individuality and character.
Throughout the past thousands of years, people had already begun experimenting
with changes in their hair color. Through the use of pigments found in insects, plants, and
berries, a new trend evolved to this very day. However, the practice involved through this
natural process often meant laborious hours for a blotchy hair job that never truly lasted.
This all changed with the invention of the synthetic hair dye in 1907 by French chemist
and L’oreal founder, Eugene Schueller. By customizing and utilizing the chemical
ingredients in fabric dyes for the permanent colorant in hair, Schueller formulated the
first synthetic hair dye for commercial use [1]. His innovation gave rise to the eventual
beginning of a worldwide trend in hair cosmetics found today. Since the birth of
Schueller’s artificial hair dye, a wide variety of alternative hair dyes can be found these
days. The most common and basic hair dyes range from permanent, semi-permanent, and
temporary hair colors. Although hair is technically considered ‘dead’, many consumers
misunderstand the unintended damages hair dying may pose. Many hair dye companies
have advertised their products as safe, but consumers need to be more educated and
cautious of what’s inside the chemical hair dye products as opposed to the box of the hair
product itself. Just how safe is hair dying and what chemicals are there?
The Basics on Natural Hair Color:
The genetic makeup of a person’s DNA largely attributes to the difference in hair
color we see in individuals. Variations in size and types of melanin are the primary
determinants that give the pigmentation found in human hair color. The two principle
types of melanin are eumelanin, which accounts for the black and brown color in hair,
and pheomelanin, which produces the yellow and red pigment [2]. The basis of hair color
can then be assessed through the amount in production and density size in these two
melanin types. An absence in both eumelanin and pheomelanin results in white or gray
hair while a preferential amount of eumelanin or pheomelanin results in black to brown
or yellow to red hair color, respectively. In addition, the density size of eulemanin and
pheomelanin influences the contrast of how light or dark the hair color will be [2]. Lastly,
external factors such as race, stress, diet, age, and medical conditions can affect a
person’s hair color as well.
The Biology of Hair Strands:
In analyzing a person’s hair color, the structure of the hair must be examined
before determining how hair deposits work. The hair has two main parts, the hair bulb
and the hair shaft. The hair bulb is where the hair strand is formed underneath the scalp.
The hair shaft is the exterior layer where the hair strand protrudes out. The hair itself is
made up of three layers. It has the cuticle, cortex, and medulla. The cuticle has
overlapping cells that look like fish scales when examined microscopically [3]. The
cortex is where the two types of melanin, eumelanin and pheomelanin, are stored [3]. It
also supports the hair’s structure and texture. Lastly, the medulla is the hollow shaft
inside the hair [3] (refer to figure 1).
Figure 1: The Biological Framework of a Single Hair Strand: The structure of the hair
strand consists of the cuticle, cortex, and medulla [2].
How Different Types of Hair Dye Work:
Permanent hair dye, or oxidation dyes, work by penetrating deep down the shaft
of the hair. In general, the formulation in oxidation dyes usually contains less than six
percent of hydrogen peroxide (the oxidizing agent) and an ammonium hydroxide solution
that includes dye intermediates, which produce active hair dyes through chemical
reactions, and preformed dyes that are added to enhance the hair color [2]. The
application of oxidation dyes usually begins when two separate packages of the ammonia
dye solution and the hydrogen peroxide solution are combined together to form the dye
solution. Once a homogenous mixture has been made, they are applied to the hair. As the
solution comes into contact with the hair, the hair strands will expand and the hair’s
surface layers become detached causing the preformed dyes and dye intermediates to
react and penetrate deep into the hair’s shaft to form the hair dye [2] (see figure 2). Over
time, the depth of hair color will progress as the intensity of penetration and chemical
reaction in the hair shaft take place. Alternatively, a progressive dye is another type of
permanent hair dye that is often used in place of oxidation dyes. Progressive dyes
essentially work like oxidation dyes, but the dye contains lead acetate that gradually
changes the color of the hair.
Semi-permanent hair dyes last longer than temporary hair dyes but are different
from permanent hair dyes as they can fade and wash out after some degree of
shampooing (about a few weeks). Compared to permanent hair dyes, semi-permanent
hair dyes penetrate somewhat into the hair shaft, although not as intensely as permanent
hair dyes and contain little to no hydrogen peroxide or ammonia in the solution [3]. The
process in semi-permanent hair dyes work by using small molecules of preformed dyes
that cross into the hair’s cuticle layers to enter the cortex of the hair beneath the cuticle
layer [3] (see figure 2). These color molecules do not attach tightly to the hair’s protein.
Thus, they do not react or change the hair’s natural pigment. Since semi-permanent hair
dyes penetrate partially, the color saturation is often subtle and will depend on the
person’s natural hair color, thickness in hair strand, and size in hair pores.
Temporary hair dyes do not last more than a few shampoos (about a few days).
Like semi-permanent hair dyes, they also contain no ammonia or hydrogen peroxide like
permanent hair dyes do. Yet, they are different from semi-permanent and permanent hair
dyes since they do not penetrate into the hair’s strand at all. Instead, temporary hair dyes
simply remain outside the hair’s shaft by coating over the hair strand like paint [3] (see
figure 2). They do not need mixing in order to become active and thus are considered a
one-element product.
Figure 2: Permanent, Temporary, and
Semi-Permanent Hair dye Penetration in Hair Cuticle: The differences in cuticle
penetration of the hair’s shaft are demonstrated by the three main categories of hair dye
products [4].
Skin Irritation and Allergy in Hair Dye Application:
A large majority of people who dye their hair experience some form of skin
irritation or allergy, whether mild or strong. The main culprit of these allergic reactions
and irritants come from skin sensitizing ingredients such as p-phenylenediamine, ptoluenediamine sulfate, and o-chloro-p-phenylenediamine among other related aromatic
amines found in common hair dyes [5]. Of all skin sensitizing ingredients, pphenylenediamine is the most commonly used, and thus is the primary interest when
allergic reactions are encountered. Such allergies occur since the hair’s shaft is directly
connected to the scalp of the skin. This triggers contact dermatitis symptoms such as
itchiness, redness, inflammation, swelling, or rashes around the person’s scalp, face, ear,
neck, and eyelids [6].
Application of hair dyes; especially oxidation dyes are the focal point in skin
irritants and allergies since chemical reactions take place that allows for penetration into
the hair shaft and consequently seeps through the skin’s outer dermis. These allergic
reactions caused by hair dyes have been classified as hypersensitive or type IV reactions
by dermatologists [7]. According to the medical dictionary, hypersensitivity is the body’s
response by the immune system when foreign substances invade the body’s physiological
processes. Type IV reactions are triggered from different immune-response mechanisms
in the localized region of the body where the product application is administered [7].
As such, the incidence of allergy and skin irritation is large among consumers such as
hairdressers and clients, where the vast majority of chemical dyes are used. When
exposure of chemical hair dyes provoke skin irritation and allergies, it is important to
emphasize the identification of these chemical ingredients in implementing lower risks.
P-phenylenediamine Associated Health Risks:
In discussing health concerns relating hair dye products, no matter what haircoloring product you use, all types of hair dyes have their own associated hazard and
safety risks. The probability of any increase in risks multiplies as the usage of any hair
dye product grows. One of the common key ingredients known to be highly toxic is PPD.
It has been labeled a carcinogen by the Center for Disease Control. Typically, PPD has
been used as an accelerator in speeding up the hair dying process. The toxicity of PPD
has been known to cause contact dermatitis, chemosis, and even permanent blindness due
to eye contact [8]. Ingestion of PPD causes Rhabdomyolsis, which is the main cause of
acute renal failure [9]. A sudden kidney breakdown in acute renal failure means an
inability of the body to remove certain waste, fluids, and electrolytes that gather up in the
body, according to the medical dictionary. Such kidney failure can be deadly since a
blockage of waste accumulates inside the body that can cause in imbalance of important
nutrients, vitamins, and minerals. According to the medical dictionary, these potential
complications include fluid buildup causing shortness of breath, inflammation of the
heart, and muscle weakness through increased levels of potassium, permanent kidney
damage, and even death. Once acute renal failure develops, the loss of life is high. PPD
promotes rhabdomyolysis through calcium release from the endoplasmic reticulum,
which follows permanent contraction changes in the muscle’s structure [7]. Since the
body’s organs are interconnected with one another, the toxicity of PPD further
contributes to other causes of sickness as the kidney’s commission to expel waste falls
through. The necessity in the removal of waste is vital as harmful or poisonous
substances, such as PPD, causes a lack of oxygen transport to the kidney’s cell [7]. This
inadequate supply of oxygen ultimately damages the biological framework in the
kidney’s ability to achieve maximum filtration, thus leading to liver disease, lung and
heart complications, and other illnesses. In establishing acute renal failure, the presence
of myoglobin in urine is analyzed. Since myoglobin (molecular weight of 17 kDA) binds
to plasma proteins, it easily escapes into the urine since it is extremely minuscule [7]. An
absence of myoglobin in the urine will present the diagnosis of the disease. The Journal
of the National Cancer Institute has suggested PPD may increase cancers such as nonHodgkin’s lymphoma, multiple myeloma, breast cancer, leukemia, and bladder cancer
[10]. Although, other reports have found this to be contrary, it is still being investigated
and updated regularly.
Other Chemical Ingredients Safety Risk:
Another common ingredient used for darkening hair is coal tar. Since coal is very cheap,
more than 70% of hair dying products contains this dangerous ingredient [10]. It is easily
absorbed into the skin and allergic symptoms have been shown after ten years of use [10].
The third most common hair ingredient is lead acetate. Like PPD, it is also listed as a
possible carcinogen. Once lead is absorbed into the bloodstream, it distributes throughout
the body. Since lead has a higher affinity for sulfhydryl groups than calcium ions, it is
able to bind to these calcium-activated proteins much tighter than calcium ions, thus
inhibiting vital cellular functions in multiple enzyme systems [11]. This leads to a
deficiency in nutrients and abnormalities, such as mental disorders, found to cause
developmental problems in children and pregnant women. Other ingredients in hair dyes
that are also worth mentioning are DMDM Hydantoin, Ammonia, and Resorcinol.
DMDM Hydantoin is a preservative that has been linked to immune system problems
[10]. Ammonia has been found to be toxic and corrosive causing skin inflammation as
well [10]. Resorcinol has been classified as an irritant and possible carcinogen [10].
FDA Regulation:
Since there is a high concern of safety in application of hair dye products, the
Food and Drug Administration’s office (FDA) of Cosmetics and Colors are often notified
when hair dyes warrant potential health risks and problems. When such complaints are
reported, the FDA evaluates the cause of the product and looks for recurrent trends of
similar complaints and reports. The FDA then conducts a follow-up and decides if the
product should be removed from the market based on evidence. As with hair dyes, many
consumers have reported such reactions that have ranged from irritation, redness, and
burning. In severe cases, some consumers have even reported migraines or difficulty
breathing. Such causes are known to be from a lack of proper use or from ingredients that
are allergenic or toxic discussed previously. According to the FDA, coal-tar ingredients
found in hair dye are known to be allergenic [10]. However, even if coal-tar ingredients
may be harmful, the cosmetics industry may be able to escape FDA regulation if they
simply slap on a warning label that notify consumers to do a skin patch test before actual
use. A skin patch test is where a consumer applies a small amount of the product onto a
small area of the skin to determine if any adverse reactions form. The problem is that
most people don’t read the warning label. Those who actually perform a skin patch test
often don’t see any harmful reactions since the area of application is often too small to
cause an immediate response. There are even some people who do the skin patch test
once and think they’re okay to bypass it the next time around. However, every brand of
hair dye product is different in regards to color and ingredients and as such, shouldn’t be
disregarded so carelessly. This means that hair dye ingredients, such as coal tar, may be
used by millions of people even if they are shown to be harmful.
In contrast, the regulation of hair dye products in the European market serves as a
better example of the cosmetics industry. As with the FDA, the European market is
regulated by the Cosmetic Directive. Within the Cosmetic Directive, they have their own
scientific committee who assesses each hair dye product based on the ingredient’s
hazardous properties and the resulting exposure of the product’s use [7]. After a thorough
review of the product, the Cosmetic Directive generally approves of any restricted or
prohibited ingredients in hair dyes. The information is then voluntarily published online.
Recommendations for Hair Dye Safety:
In concluding an overall analysis from the basics of hair pigment and structure to
the dangers of chemical compounds found in common hair dye products, it is imperative
to limit the use of controversial ingredients known to cause hazard. By introducing less
chemical ingredients that induce allergies or irritation, the consumer’s potential health
risk will be lowered dramatically. Such suggestions can be made through more detailed
instructions, or education in safety measures, such as wearing protective clothing and
eyewear. In addition to minimizing exposure to harmful chemical ingredients, the
consumer should be smart and ask for hair dye products that do not contain harmful
ingredients such as PPD, resorcinol, or ammonia, commonly known to be toxic.
On the horizon are new developments currently being made for safer hair dyes. A
great example is the Advanced Cosmetic Technologies. The company uses small color
molecules to absorb into the hair’s shaft without detaching the hair’s shaft like oxidative
dyes do [12]. The companies’ products are PPD, resorcinol, and ammonia free, using a
plant breeding patent technology for permanently coloring the hair [12]. According to the
American Chemical Society, there is also new research being made where substances are
made that stimulate the genes in producing the color pigment in hair follicles. Such
alternatives will lower the risk in consumer safety and provide better examples of proper
hair coloring products than those currently available in the market today. Therefore, a
closer inspection in the ingredients of chemicals used in hair dye products should always
be a determinant in giving it a clean bill of health.
Work Cited
[1] "The Birth of Permanent Hair Colour and L?Oreal - Herbatint UK." The Birth of
Permanent Hair Colour and L?Oreal - Herbatint UK. Herbatint, 2006. Web. 12 Apr.
2013. <http://www.herbatint.co.uk/herbatint/features/herbatint-article.php?id=28>.
[2] Raber, Linda. "Hair Color: Chemistry to Dye For." Chemical & Engineering News
(2000): 52-53. Chemistry. 13 Mar. 2000. Web. 12 Apr. 2013.
<http://www.csklsc.edu.hk/chemistry/chemilife/chemmatter/02/02_APR.PDF>.
[3] "Aging-It's Not Just Face Value." P&G Beauty & Grooming. N.p., n.d. Web. 13 Apr.
2013. <http://www.pgbeautygroomingscience.com/assets/files/research_updates/P>.
[4] Hair Dye Penetration. N.d. Photograph. The Natural Haven. Web. 12 Apr. 2013.
<http://www.thenaturalhavenbloom.com/2009_06_01_archive.html>.
[5] Robbins, Clarence R. The Chemical and Physical Behavior of Human Hair. New
York: Van Nostrand Reinhold, 1979. Print.
[6] "Hair Dye Allergy." About.com Allergies. N.p., n.d. Web. 13 Apr. 2013.
<http://allergies.about.com/od/contactdermatitis/a/Hair-Dye-Allergy.htm>.
[7] Schlatter, Herald, Timothy Long, and John Gray. "Shibboleth Authentication
Request." Shibboleth Authentication Request. Wiley, 30 June 2007. Web. 13 Apr. 2013.
<http://onlinelibrary.wiley.com.libproxy.usc.edu/doi/10.1111/j.14732165.2007.00318.x/full>.
[8]Singlet, Sumeet, Sanjeev Miglani, Pulin Gupta, and AK Agarwai. "Result Filters."
National Center for Biotechnology Information. U.S. National Library of Medicine, JulyAug. 2005. Web. 13 Apr. 2013. <http://www.ncbi.nlm.nih.gov/pubmed/7909678>.
[9]Sampathkumar, Krishnaswamy, and Sooraj Yesudas. "Abstract." National Center for
Biotechnology Information. U.S. National Library of Medicine, 28 Oct. 0005. Web. 13
Apr. 2013. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2700586/>.
[10] "How Much Do You Know About Hair Coloring?" Surviving Hair Loss. N.p., n.d.
Web. 12 Apr. 2013. <http://www.surviving-hairloss.com/hair_coloring.html>.
[11] Rowden, Adam K., and Tarakad Ramachandran. "Pathophysiology and Etiology of
Lead Toxicity ." Pathophysiology and Etiology of Lead Toxicity. Medspace, 30 Sept.
2011. Web. 13 Apr. 2013. <http://emedicine.medscape.com/article/2060369-overview>.
[12] Clute, Mitchell. "Hair to Dye for New Products Offer More Shades." Natural Foods
Merchandiser (2009): 86. Proquest. Penton Business Media, Inc. and Penton Media Inc,
Mar. 2009. Web. 12 Apr. 2013.
<http://search.proquest.com.libproxy.usc.edu/docview/219611957/abstract?accountid=14
749>.