Your Place for Information on the Science of Hair. Learn the Science Behind the Beauty.
- Learn more about your hair composition,Find out how proteins, raw elements, amino acids and bonds work together in forming hair fiber.
- Learn how relaxers are utilized to loosen bonds within the cortex of your hair,Discover how the different types of relaxers are used for your specific hair condition
- Learn more about the importance of seeing a professional stylist,Learn all about the professional consultation needed to assess the products and services needed
Science of Hair
Human hair is an appendage which grows from follicles, tube like sacs in the scalp or skin containing the hair root. The hair that we cut, relax, color and style is a non-living fiber comprised of keratinized protein. Within the hair follicle cells are produced. These cells mature in an upward moving process through the follicle. This maturing process is known as keratinization. During keratinization cells absorb keratin, a fibrous protein. As the cells continue to move upward they lose their nucleus and die off, producing the non-living keratinized cells (appendage) that emerge from the scalp.
Hair Composition
Hair is comprised of many contributing factors. Proteins, raw elements, amino acids and bonds work together in forming hair fiber. The dominant contributor in the composition of hair is protein, accounting for 91 percent of hair fiber.
Amino acids, the building blocks of protein, are made up of COHNS elements, (Carbon, Oxygen, Hydrogen, Nitrogen and Sulfur).
The percentage of COHNS elements in hair is as follows:
Element
|
Percentage in Normal Hair
|
Carbon
|
51%
|
Oxygen
|
21%
|
Nitrogen
|
17%
|
Hydrogen
|
6%
|
Sulfur
|
5%
|
These elements form bonds called side bonds which link together the long chain of amino acids known as the polypeptide chain. This chain forms a helix by creating spiral movement that intertwines.
The following are the amino acids and the percentage found in hair fiber:
Cysteine
|
17.5%
|
Serine
|
11.7%
|
Glutamic acid
|
11.1%
|
Threonine
|
6.9%
|
Glycine
|
6.5%
|
Leucine
|
6.1%
|
Valine
|
5.9%
|
Arginine
|
5.6%
|
Aspartic acid
|
5.0%
|
Alanine
|
4.8%
|
Proline
|
3.6%
|
Isoleucine
|
2.7%
|
Tyrosine
|
1.9%
|
Phenylalanine
|
1.4%
|
Histidine
|
0.8%
|
Methionine
|
0.5%
|
Millions of polypeptide chains reside in the cortex layer. Side bonds such as hydrogen bonds, salt bonds and disulfide bonds link together these polypeptide chains. Hair fibers are held in place by the side bonds which attribute to the elasticity and strength of hair.
A hydrogen bond can easily be broken by water or heat, and is a physical side bond. Collectively, hydrogen bonds account for one-third of hair’s strength.
Salt bonds are also physical side bonds. Strong acidic or alkaline solutions break salt bonds because they are affected by changes in pH. Like hydrogen bonds, salt bonds also account for approximately one-third of hair’s strength.
Disulfide bonds differ from hydrogen and salt bonds because they are not physical side bonds. Disulfide bonds are chemical side bonds. Disulfide bonds link together two sulfur atoms attached to cysteine amino acids within the polypeptide chains. Chemical hair relaxers and permanent waves chemically alter the hair’s disulfide bond. Disulfide bonds cannot be broken by water or heat.
Hair Structure
The appendage that projects from the epidermis is known as the hair shaft. The hair shaft is comprised of three layers: the cuticle, cortex, and medulla.
The cuticle is the hair’s outer most layer which has shingle or scale like cells that overlap. These cells work defensively to prevent damage to the hair’s inner structure and to control water content of hair fiber. The middle structure includes the cortex which provides strength, color and texture of the hair. The innermost structure is the medulla layer which is only present in large thick hairs. The shingle like cells of the cuticle layer point toward the ends of the hair and are raised during chemical processes. When the cells are raised, solutions are able to enter into the cortex layer.
The improper use of tools, heat, excessive manipulation and chemical over-processing can cause damage to the cuticle layer of the hair, weakening the integrity of the hiar. To prevent hair damage, take a proactive approach to healthy hair care by scheduling an appointment with a licensed stylist.
The middle layer of the hair is known as the cortex, and it has many different functions. Approximately 90 percent of hair’s total weight lies within the cortex layer. Elongated cells form a fibrous substance that gives strength and elasticity to the hair. The cortex also houses the pigment (melanin) that gives hair its natural color. Services such as chemical hair relaxing, thermal styling, wet setting and hair coloring oxidation cause temporary and permanent changes to the hair. These changes take place in the cortex layer.
There are two types of melanin that can be found in the cortex layer of the hair: eumelanin and pheomelanin. Eumelanin produces brown and black color, and is the most prevalent type of melanin. Pheomelanin imparts yellow, blonde, red and auburn hues. Natural hair color derives from a peomelanin and eumelanin ratio combined with the size and number of pigment granules. When hair is gray, there is an absence of melanin pigment in the cortex layer.
The medulla, also referred to as the pith or marrow of the hair, is the innermost layer. Composed of round cells, this layer is normally found in thick and/or coarse hair. Naturally blonde and fine hair generally does not have a medulla. The function of this layer of hair does not affect the hair care services conducted by salon professionals.
Beneath the epidermis is a factory of structures working together to promote hair growth. The hair root, the portion of hair underneath the scalp’s surface, works with the dermal papilla, hair bulb, arrectorpili, sebaceous or oil gland and follicle in the formation of hair.
The dermal papilla contains the blood supply and nerves that produce nutrients for the hair. These vital nutrients are needed in order for hair to grow. The dermal papilla is shaped similar to a cone and sits inside the hair bulb.
The hair bulb is another important factory producer. It is located at the base of the hair strand, and its shape is like a club. It acts as a cover for the dermal papilla.
The arrectorpili is a familiar hair factory worker. Its colloquial name is goose bumps. This small muscle fiber lives in the bottom of the hair follicle. Changes in temperatures and fear often cause the muscle fiber to contract, making hair stand straight up. The results, goose bumps, last a few seconds.
The oil glands of the skin are called sebaceous glands. These glands are connected to the hair follicle and secrete sebum, an oily substance that lubricates the hair.
Types of Relaxers
Chemical hair relaxers are designed to straighten extremely curly, coiled or tightly coiled hair by breaking the disulfide bonds found within the cortex layer of the hair. Hydroxide and Thio are the most common types of hair relaxers. Hydroxide relaxer types include sodium hydroxide, potassium hydroxide, lithium hydroxide and guanidine hydroxide.
These relaxers can be marketed as base and no base relaxers. Base relaxers require stylists to base the client’s entire scalp with a protective cream prior to the chemical relaxer application. No base relaxers have a protective cream built within the relaxer that settles onto the scalp according to the client’s body temperature. Although no base relaxers have a thin, oil like protective cream within the relaxer system, most stylists use a base cream around the ears and hairline for added protection.
Relaxer Q&A
How Do Relaxers Work?
During a chemical relaxing procedure of a hydroxide relaxer a process called lanthionization occurs, which is the breaking of a disulfide bonds to alter the curl pattern of the hair. During this process the curl pattern is loosened or relaxed. The cortex is thus elongated, stretching the original curl pattern, therefore making this a permanent alteration.
What are the different types of Hydroxide relaxers?
There are several types of Hydroxide relaxers aka Metal Relaxers which are sold to professionals and consumers with no mixing requirements. The ionic metals include sodium (Na), lithium (Li), and potassium (k). These metals are combined with oxygen (o) and hydrogen (h), forming ionic compounds known as relaxers which include the following active ingredients: sodium hydroxide (NaOH), potassium hydroxide (KOH), and lithium hydroxide (LiOH). Sometimes calcium (CaOH) is added to hydroxide relaxers, but it is not used solely to relax hair
What is the difference between Lye and No Lye Relaxers?
The main active ingredient in a Lye Relaxer is Sodium Hydroxide (NaOH). Sodium Hydroxide relaxers are very effective in breaking down the hair’s bonds (straightening the hair) quickly. Because it processes quickly it is also the most commonly used relaxers by professionals. Through speedy and precise application, professional stylists are able to apply the relaxer evenly, process the relaxer in a timely manner and rinse thoroughly with a neutralizing shampoo to avoid damage and potential irritation during the chemical process.
Lithium hydroxide (LiOH) and potassium hydroxide (KOH), calcium hydroxide (CaOH) and Guanidine hydroxide relaxers are marketed as No Lye relaxers. Although these ionic compounds are not lye, hydroxide is an active ingredient. No lye relaxers are ideal for someone with a very sensitive scalp, as the chemicals and pH level of these type of relaxers are milder than lye based relaxers. No lye relaxers are commonly associated to dryer hair due to calcium buildup. This can easily be addressed through the use of a clarifying shampoo to remove dull deposits and a deep conditioning treatment to add moisture back to the hair.
What is a Low Lye relaxer?
A Low Lye relaxer has the lowest concentration of sodium hydroxide which is less than 2.5%. It is equally as effective as other Sodium Hydroxide relaxers however much more mild due to the percentage of active ingredient. The low lye relaxer gently loosens the bonds for increased manageability, while maintaining some level of texture in the hair.
Which type of relaxer is better for the hair?
It is best to seek the advice of a licensed professional stylist to determine the best relaxer system for your hair type. A full consultation should be conducted by a professional prior to using a particular type or strength of relaxer.
What if I have a sensitive scalp? Which type of relaxer should be used?
A professional stylist can analyze your scalp and hair to determine if relaxing is the best option for you, and if so, which type of relaxer is best. Often times Guanidine hydroxide relaxers and calcium hydroxide relaxers are recommended for clients who have a sensitive scalp, however a professional stylist will be able to recommend the best relaxer option for you.
Why are there different relaxer strengths? Don’t they all relax the hair the same way?
The level of hydroxide used in relaxers determines the strength. For example, super strength contains a higher concentration of sodium hydroxide than a regular strength relaxer. Although the result from a relaxer, irrespective of strength, is straighter more manageable hair, the strength of the relaxer used to achieve the result is very important. The goal is to avoid hair and scalp damage based on the texture of the hair. As a precaution, at home relaxer application is not recommended. A professional stylist will be able to assist in determining the best relaxer option for you.
What is pH?
The pH is a measure used to determine the acidity and alkalinity of a substance. The scale is represented by numbers ranging from 0 to 14 where 7 is neutral. Greater than 7 on the pH scale is more alkaline and less than 7 is more acidic. The pH of hair ranges between 4.5 – 5.5. Lye relaxers range from 12 – 14 and no-lye relaxers range from 9 – 11.
Can any type of shampoo be used after a relaxer?
Following a relaxer you should always cleanse with a Neutralizing shampoo. A neutralizing shampoo will ensure that you remove all traces of chemical residue and restore the hair to its resting pH level of 4.5. The pH of a hydroxide relaxer is typically 13 or higher which is considered a high alkaline concentration. Therefore an acid-balanced shampoo must be used to neutralize the hydroxide, and to return the hair and scalp to a normal pH level.
What is the processing time for a relaxer?
Processing times vary from client to client. However, most processing times are a maximum of 20 - 25 minutes.
If you relax the hair until it is bone straight, you are essentially over relaxing the hair. This removes any degree of elasticity, thus weakening the hair. Over a period of time of continuous over relaxation, blow drying and hot curling, the hair will become damaged and prone to breakage. To avoid irreparable damage and maintain the integrity of the hair, Design Essentials recommends straightening the hair 65% - 75% straight.
What is a thio relaxer, and how does it differ from a hydroxide relaxer?
Thio relaxers are also used to straighten hair. The primary agent, ammonium thioglycolate (ATG)is also used in permanent waving. Hydroxide relaxers and thio relaxers should not be used interchangeably. Overlapping these chemicals can cause extreme damage to the hair, and can result in hair loss.
Thio relaxers differ from hydroxide relaxers in a few ways. The pH of thio relaxers is typically around 10 whereas the pH of hydroxide relaxers is approximately 13. Also, an oxidizing agent like hydrogen peroxide or sodium bromate is used to neutralize thio relaxers. During this process the disulfide bonds are reformed that were broken by the relaxing process. When using hydroxide relaxers, the broken disulfide bonds are permanently broken and cannot be formed again. Oxidizing agents should not be used with hydroxide relaxersConsultation
One of the benefits of seeing a licensed stylist is receiving a professional consultation. This is perhaps the most important part of hair care services. The consultation establishes communication between the client and the stylist, and gives a clear direction for the desired look. The client’s expectations can be set during this session, and the hair stylist can determine which method, products and services are needed. In addition, clients get the perfect opportunity to explain the likes and dislikes about their hair and previous services.
The consultation usually takes anywhere from 5 to 20 minutes. It is important to divulge all necessary hair history, at home regimens, products used and treatments used when asked by the stylist. Leaving out key information can cause less than desired results. Allergies and medications should also be given so the stylist can take extra precaution when selecting and applying products.
During an initial consultation the stylist will determine the condition of the hair by analyzing the texture, curl pattern, growth pattern, elasticity, porosity, length, and density.
Hair Texture
Hair texture is defined in three basic ways: coarse, medium and fine. The diameter of each individual hair strand determines the texture of hair. For example, coarse hair has a greater diameter than medium or fine hair. Coarse hair tends to be more resistant to chemical services such as relaxer, color or perm, because it has so much more substance to it. Whereas fine hair is very easy to process and often times prone to over-processing and damage from chemical services because it is so thin. Stylists can determine if hair is coarse, medium or fine by holding a single strand of dry hair between two fingers.
Curl Patterns
Curl patterns range from straight, loose waves, wavy, curly, tightly curled, coiled, and tightly coiled.
The curl pattern speaks volumes to the stylist in regards to its own special characteristics such as: prone to frizz, easy or resistant to style, dryer time, moisture content and many more.
Growth Patterns
Prior to performing services on clients, especially haircuts, stylists should analyze the client’s hair growth patterns. Cowlicks, whorls and hair streams occur as a result of growth patterns. Hair follicles rarely grow straight out from the scalp which would reflect 90 degrees. Most hair growth patterns grow at various degrees.
Cowlicks are generally seen around the front hairline where a small group of hairs stand straight up.
Whorls form in a circular pattern and can be seen in different areas of the head, but mainly in the crown of the head.
Follicles slope in the same direction it causes hair to flow in the same direction. This is called a hair stream. For example, a natural part is formed when two streams flow in opposite directions.
Elasticity
Just think of a rubber band. Elasticity is the ability of hair to stretch and contract. Stylists may choose to perform a strand test to determine the elasticity of hair. When stylists test the elasticity of hair, strands are selected from different areas of the head. Stylists hold a wet single strand of hair and stretch the hair. If the hair returns to its original form without breaking just like that of a rubber band, it is considered normal elasticity.
Good elasticity is represented by hair stretching approximately 20 percent of its natural length when dry and up to 50 percent when wet with no breakage.
The symptoms of low elasticity include breakage, hard to hold curls and styles. The chemical services selected must have a lower pH to prevent damage and over-processing. When stylists test the elasticity of hair, strands are selected from different areas of the head.
Porosity
Porosity is the hair’s ability to absorb water. The condition of the cuticle layer of the hair is directly related to the hair’s porosity. Hair that is resistant to penetration has a compact cuticle layer and is considered to be normal healthy hair. The porosity of hair can be categorized as low porosity, average porosity and/or high porosity.
Low porosity – Resistant hair: the hair’s ability to absorb water is low, and the cells of the cuticle layer are not raised, which prevents solutions from entering into the cortex layer of the hair.
Average porosity – Normal Hair: the cells of the cuticle layer are slightly raised.
High porosity – Dry, brittle or damaged hair:the hair strand may feel rough, and cuticle layer cells are raised. The porosity can be checked on dry hair by moving the thumb and fore finger up and down the single strand. Generally high porosity can be determined easily because the hair is usually in an extremely unhealthy state.
Length
Hair typically grows about 6 inches per year. During this same period as a number of strands may be growing, your hair will also experience shedding at the same time. Many factors determine the rate and length of hair growth including diet, hair care practices, genetics, health, medication, and hormones.
Hair grows through three cycles: anagen, catagen and telogen.
The Anagen Phase is the active growing cycle. During this phase, hair grows 1cm every 28 days and stays in this growth phase for 2 to 6 years. Depending on the length of time one stays in this active phase will determine the common length of their hair. If you find that no matter what you do, your hair only grows to a certain length then that means you have a short active phase of growth.
The Catagen Phase is known as the transitional phase, which lasts approximately 1 to 2 weeks. During this time growth stops and the papilla begins to separate from the follicle. This process cuts the hair off from its blood supply and from the cells that produce new hair. Only 3% of all hair is in this phase at any time.
The Telogen Phase is the resting phase and accounts for 10% - 15% of all hair. This phase lasts 5 to 6 weeks. During this phase the hair follicle is at rest and if you were to pull out a hair you would reveal a solid white mass at the root of the hair. This is the typical phase for shedding, which amounts to 25 – 100 hairs per day.
After the Telogen Phase the cycle begins again and new hair is formed during the Anagen phase.
Density
Do you know how many hairs the average head contains? The answer is 100,000.
The density of hair is measured by the number of individual strands per square inch. On average most people have approximately 2,200 hairs per square inch or 2.5 cm. One’s natural hair color on average can determine the density of the hair. For example, a natural blond on average has 140,000 hairs, natural brown – 120,000, natural black – 108,000, and natural red – 90,000.
Hair Myths
Myth: Dandruff shampoo will strip relaxers.Fact: Most anti-dandruff shampoos have an active ingredient to control the symptoms associated with dandruff. The active ingredient in Design Essentials Therapeutics Anti-Itch Shampoo is Pyrithione Zinc (2.0%), which will not strip relaxers. Formulated with moisturizing agents as well, the product is designed to control flaking, itching and irritation caused by scalp conditions such as Dandruff and Seborrheic Dermatitis while depositing moisture into the hair.
Myth: Dirty hair grows faster than clean hair.
Fact: Clean hair is better for the hair and scalp. There is no scientific data that suggests dirty hair grows faster. On average hair grows .44mm per day. Buildup of products and oils can cause severe scalp problems if not properly cleansed on a regular basis, which could inhibit hair growth.
Myth: Split ends can be repaired.
Fact: Split ends can be repaired by clipping them and preventing them from causing damage to the rest of the hair strand. Hair should be cut or trimmed once every 6 weeks.
Myth: Shears don’t make a difference when cutting hair; any type of scissors can be used.
Fact: Professional shears do make a difference in the precision of a haircut. Dull unsharpened shears can drag and pull the hair strands which can prevent proper movement and precision in the finished look.
Myth: Professional products are no different than nonprofessional products.
Fact: Professional products like Design Essentials have a higher concentration which requires less product to be used. In addition, higher quality ingredients are used to ensure that the products are safe and will deliver based on brand promise – preserving the health and integrity of the hair.
Myth: It doesn’t matter what type of shampoo you use as long as you use a good conditioner.
Fact: Shampoos come in four basic categories: Clarifying, Moisturizing, Neutralizing and Special Care or Treatment. Clarifying shampoos are great for removing product build up and chlorine. Moisturizing shampoos helps to detangle the hair and adds special conditioners to smooth the cuticle layer of the hair. Neutralizing shampoos stop the chemical relaxing process and must be used during the relaxing process. Neutralizing shampoos also contains an agent that indicates the pH of the hair; the shampoo is pink until all of the relaxer has been removed from the hair. Special Care or Treatment shampoos are used for color treated hair and/or scalp issues. Selecting the right shampoo is imperative in getting the best possible results.
Myth: It is okay to relax edges every two weeks.
Fact: The temple areas should not be relaxed every two weeks. Normally the density of the hair is lower around the edges, and it is almost impossible to prevent over processing if the hair is relaxed every two weeks. Professional stylists can give you the appearance of a relaxer by using special techniques, styling tools and professional products.
Myth: It is safe to use heated tools on the hair every day.
Fact: Heat damage can occur as a result of over-use or misusing heated tools like flat irons, curling irons and blow dryers. Misuse can also lead to hair breakage and shedding. To maintain your thermal style, it is best to pin curl or wrap your hair and secure with a satin head wrap at night. This will allow you to preserve your thermal style without putting too much heat in your hair.
Healthy Maintenance
Healthy Hair Maintenance should be a proactive and not a reactive practice. Too often consumers wait until their hair is extremely damaged before seeking the help of a licensed cosmetologist. Trichology is the scientific study of hair, hair care and its diseases. It takes years to master and understand how to properly care for the hair and treat the conditions of the hair and scalp. If you are experiencing problems, breakage, shedding and/or scalp irritation, make an appointment with a licensed stylist for a full consultation on how to better manage your hair.
Take special precautions to ensure that you’re being proactive every day in your hair care practices. Shampoo your hair regularly with recommended shampoos as directed by a salon professional. Not only should you cleanse your hair and scalp on a regular basis, but you should also clean all of your combs, brushes, hair rollers and tools such as blow dryer attachments, flat irons and curling irons. Cleaning your tools can prevent irritations caused by unclean items. In addition, cleaning your heated tools will prevent the hair from smelling like burned hair that often occurs during at home use.
Hydration practices also help to prevent breakage and shedding. Using the proper conditioning, styling and finishing agents between salon services will keep styles longer and continue to add moisture until the next salon service. Always use styling agents like Silk Essentials to protect the hair when drying and styling. Silicone, one of the key ingredients in thermal protective products, is heat resistant. This compound helps to coat the hair shaft and helps to secure moisture into the hair shaft. It also prevents heat damage caused from tools as well as the sun’s UV rays.
As a woman, no other physical feature better accentuates your femininity than your hair. So what’s a girl to do when she starts losing it? Many are unaware just how prevalent hair loss in women has become. Experts estimate that nearly 20 million women in the U.S. are suffering from hair loss, 40% of which are under the age of 40. The good news is that you can not only put an end to premature balding and thinning of the hair but also restore hair in some of those “patchy” regions.