Admiring the Adaptable Qualities of Hair

This may come as a surprise to you, but the hair on your head is
dead. Don’t feel too bad, though — everyone else’s hair is dead,
too. So why waste time taking care of something that’s dead? And if
it’s not alive, then how can you make your hair look better — or
last longer?
Even though your hair is dead, how you treat it can make it look
much better — or worse — because hair has many attributes of a
living organ and can repair itself under the right conditions.
Stripping away the coating:
Inside your hair
It’s easier to care for your hair properly if you understand how the
individual parts of a human hair are affected by the way you care
for it. In this section, we look at the anatomy of a human hair.
Cutting into a hair
Hair is made up of dead compressed cells produced about
1
⁄4 inch
below the skin. At the end of each hair is the hair bulb, which is
essentially the factory for making the hair; this part of the hair is
alive and working all the time. Each hair has its own bulb, and
damage to the hair bulb can result in permanent loss of that hair.
(Turn to Chapter 2 for a look at the anatomy of a hair follicle.)
Each individual hair can be compared to an electrical wire. If you
cut into a wire, you see that it has a rubbery outer covering and
twisted or bundled inner wires that carry electricity. Human hair is
made up of an outer covering called the cuticle that contains indi-
vidual bundles of hair called the cortex. The cuticle gives the hair
shaft a round or oval shape. Stripping off the cuticle would leave
the hair looking like a series of out of control wires.
The bundles (also called spindles) of hair cells in the cortex are
actually made up of even smaller bundles that literally twist as
they’re made. With African American hair, the hair cells are so
heavily twisted (up to 12 times more twists per length than
Caucasian hair) as the bundles are made that the hair is kinky. The
tight twists tend to kink the cuticle, producing pointed, vulnerable
edges that make the hair more susceptible to damage. The less the
twists, the straighter the hair.
Combing the cuticles
The outer layer of the hair, the cuticle, protects the inner spindles
and bundles. The cuticle has scales that, like scales on a fish or
shingles on your roof, protect the hair within. When you take a
knife against the grain of scales on a fish, you take off the scales;
with the hair cuticle, imagine your fingers or comb rubbing against
the direction of the cuticle scales doing the same type of damage.
The scales make the cuticle porous, allowing the hair to breathe.
This is very important because the ability to hydrate hair depends
upon the porous nature of the cuticle. The scales also relate to
how the hair feels: When you stroke it one way, it feels smooth, and
the other way there’s a roughness to it.
Breaking the hair bonds
The bonds that help hold hair in a certain position can be broken
or rearranged, such as when hair is permed or straightened. There
are three types of bonds that determine the strength and the lift of
the hair:
 Hydrogen bonds: These bonds break down easily and give
hair its flexibility. Hydrogen bonds come apart when you wet
your hair and come back together again as your hair dries.
 Salt bonds: These are temporary and easy to rearrange
because they’re water-dependent and easily dissolved when
your hair is washed. Salt bonds are easily broken by weak
alkaline products like ammonia or acid solutions that contain
chlorine or copper peptide in high concentration and by
changes in pH. These bonds can be reformed by normalizing
the pH level of the hair with normalizing solutions available at
your local hair salons.
 Disulfide bonds: These are relatively permanent and can only
be changed with perming and relaxing agents. Disulphide
bonds are stronger than hydrogen and salt bonds, and there
are fewer of them than the other types. Disulfide bonds are
the most important factors in supplying the hair with its
strength and durability, and as such, they can’t be broken by
heat or water.
Wet hair can be stretched by as much as 30 percent, and you
can change the shape of the hair bonds when it’s stretched. For
example, when you put rollers on your wet hair and then allow the
hair to dry on the rollers, the hydrogen bonds take on the shape
of the rollers, which essentially sets the hydrogen bonds in this
new shape.
Keeping it greased: Sebum’s
role in healthy hair
Your scalp helps keep your hair looking healthy by supplying an
abundant and constant production of sebum, a waxy material made
by sebaceous glands. It’s secreted onto the hair as it emerges from
the scalp through pores in the skin. The sebum works its way into
the hair on the surface of the cuticle, and it’s spread through the
hair as the hair moves in the wind, by combing it, touching it, and
by hairs rubbing against other adjacent hairs.
If hair is cut short, the same amount of sebum is produced, so rela-
tively more sebum covers less hair, causing it to appear more
greasy. (It also causes the bald pate to acquire a sheen rather
quickly after showering because there’s no hair to carry off the
oil.) There’s nothing you can do about oily hair other than wash
your hair more often and use a shampoo made especially for
greasy hair.
Adolescents have unusually high sebum output, which is why so
many teenagers complain of greasy or oily hair. We’re often asked
to prescribe drugs to decrease sebum production in teenagers who
hate their greasy hair. Some professionals feel that the sebum pro-
duction can be impacted by drugs such as Propecia or saw pal-
metto (an herb; see Chapter 10), which block production of the
DHT hormone, but studies show no connection between a lack of
DHT production and decreased sebum production.