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Factors Influencing Hair Volume

Why is it so hard for some women to keep great volume? Why are some of us struggling with lank, limp head-hugging hair while others seem to have full, bouncy hair all the time? The answer is physiological in nature - we inherited a genetic tendency toward fine or limp hair.

The key physiological factors affecting volume are:4

A. Diameter - the size of each hair strand
B. Density - how much hair you have all over your head
C. Stiffness - ability of hair to hold itself away from the scalp
D. Curvature - how much natural bend/wave hair has
E. Friction - how slippery each strand of hair is
F. Cohesion - how much hair strands stick to each other

A. Diameter

Human hair diameters range from 40 microns to 120 microns. Hair texture is usually classified as follows:5

Fine less than 60 microns
Medium 60-80 microns
Thick greater than 80 microns

  

Unfortunately, there is very little you can do to permanently increase the diameter of your hair shaft, but you can maximize what you do have by making sure your hair is as healthy as possible. Maintain a nutritious, well-balanced diet, as illness and malnourishment can reduce your hair's diameter.

Fact: If you have thick hair, your ponytail can be up to twice as thick as the ponytails of your thin-haired friends!

  • Dianna's Science Advice:
    Styling products like mousse or gel can temporarily give the sensation of increased diameter by coating your hair with a polymer film
  • Danilo's Style Advice:
    Get the volume that nature didn't give you by using a regimen of styling products that work together to achieve the look you want to keep
  • B. Density

    Density is the number of hairs per square centimeter on your scalp. On average, most adults have 100,000 to 150,000 hairs on their head6 or 175-300 hairs per square centimeter. This is a big range that represents a lot of variation - depending on age and genetics, some people can have almost twice as many hairs on their head than others.

    Why Density Is Important

    1) if you have greater density, you have more hair and a thicker ponytail.
    2) when hairs are very close together they help hold each other up straighter (think of being in New York's Times Square on New Year's Eve - it would be virtually impossible to sit or lay down there).

    Fact: Did you know your hair density actually peaks in childhood and decreases as you age? Peak density is achieved in childhood and around age 16 begins to decline steadily until the age of 50, when a sharper decrease occurs.7

  • Dr. Gray's Medical Advice:
    The easiest thing you can do to maintain hair density is to keep your hair and scalp healthy. Avoid pulling out hairs by vigorous combing or too much tension on ponytails and braids. Use anti-dandruff shampoo if necessary to keep your scalp healthy and prevent itching and scratching. Severe hair loss, called alopecia, should be treated by a dermatologist.
  • Danilo's Style Advice:
    When choosing a product for thin hair, mousses are a good choice because they are lightweight and easy to spread down to the roots. Avoid heavy or waxy products that can cause thin hair to clump at the roots and give the appearance of even less hair.
  • C. Stiffness

    The technical term for stiffness is "bending modulus." This is a way of measuring the "limpness" of your hair or its ability to hold itself away from your scalp. Unfortunately, stiffness is a direct function of hair thickness. The thinner your hair, the lower the stiffness measure.

  • Dianna's Science Advice:
    Increase the stiffness of your hair mass by using styling products that contain holding polymers. Holding polymers can temporarily improve the stiffness of your hair by bonding together separate hairs - when the hairs work together, they have more natural lift and stiffness.
  • Danilo's Style Advice:
    A good haircut is very important in maximizing your hair's stiffness. Layers and texturizing create opportunities for hair to work together for greater lift and stiffness. To achieve texture, try using a styling wax.
  • D. Curvature

    This one is pretty simple. Curved or curled hair takes up more space than straight hair

    Curl vs. Straight

    Curl vs. Straight
  • Dianna's Science Advice:
    Be sure to use a foundation styler like mousse or gel to help set the curve. Heat makes the styling polymers melt and flow to increase hair-to-hair contact and provide even better long-lasting hold.
  • Danilo's Style Advice:
    Enhancing your hair's natural curls or waves is an easy way to create long- lasting volume. Use a round brush or shape your hair into a curve around your fingers to help lift the roots. Use a curling iron to add volume to ends.
  • Before setting in root curve

    Before setting in root curve

    After setting in root curve

    After setting in root curve

    E. Friction

    Friction, or the roughness of the hair fiber, also affects hair volume. If hair fibers are rough, they catch on each other and build up a network of fiber-to-fiber interaction.

    In fact, there is a direct relationship between hair friction and fullness. This is why many fine-haired women find that using the "wrong" conditioner can significantly reduce friction, making it difficult for them to achieve volume. So... a little friction is good, but watch out - too much friction can cause severe hair damage and breakage.

  • Dianna's Science Advice:
    Styling gels and mousses actually temporarily increase friction during styling to help you achieve and keep your style. They go into your hair as a smooth film but as the film partially dries they go through a temporary sticky phase (in this case, stickiness is a good thing!). This helps you hold your hair into shape while you finish drying your hair. Once the film is completely dry, it stops feeling sticky and your style is set.
  • Danilo's Style Advice:
    Although you don't want to over do it, even fine hair needs conditioning. Use a volumizing conditioner that will moisturize and protect your hair without weighing it down.

    Another way to increase friction is to color treat your hair. Experiments show bleaching increases surface friction by as much as one third.8 Color treating hair changes the chemistry of your cuticle - the important outer layer of the hair shaft. This change in chemistry makes the hair less slippery, increasing friction and making your hair feel and look fuller. But be careful - over bleaching or excessive recoloring can make your hair so rough it becomes susceptible to damage. If you do color treat your hair, be sure to use color-safe styling products that will not fade or change your color.
  • F. Cohesion

    Cohesion is the tendency for something to stick to itself. There are two types of cohesion that can hurt volume:

  • Greasy, oily buildup - this can make hair clump together and stick to the scalp. That is one reason why you want really clean hair when you start styling for long-lasting volume.
  • Static electricity - static electricity can cause hair to either flyaway or stick together. Think about your skirt sticking to your pantyhose in the wintertime. This is a result of static electricity. If you hair clings to your neck or face after taking off your hat, you are a victim of static electricity.
  • Hair generates static electricity because it is triboelectric - that means, when rubbed, it can generate electrical charge. When these charges build up cause static electricity. When opposite charges build up they attract each other and when similar charges build up they repel each other. Static electricity is worse in the winter and better in the summer. That is because the water in humid air helps dissipate static build-up on your hair. Dry winter air acts as an insulator, actually promoting the build-up of larger static charges.  

  • Dianna's Science Advice:
    Make sure to use volumizing conditioners and styling products containing ingredients like polyquaternium, quaternium 18 and stearamidaproply dimethylamine to prevent static charge build up in fine hair. These ingredients are charged and conductive. That means they help dissipate the static build-up in your hair before it gets big enough to attack your volume.
  • Danilo's Style Advice:
    Prevent greasy build-up and static electricity by choosing the right styling products for your hair and using a clarifying shampoo once a week. Regular use of a conditioner will help prevent static - just be sure to use the right amount for your hair type.


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