The Structure of Hair

Hair grows from a follicle that is located below the surface of the skin. The hair shaft, which is the only part we see, is composed mainly of keratin and is entirely dead.

Each hair has a spong inner core, the medulla, which is surrounded by a stronger layer called the cortex. The cortex is reponsible for the strength, thickness, and flexibility of the hair. It also contains melanin, the pigment that determine hair colour. Any product designed to bring about permanent change, such as bleaches, tints and perms, must penetrate the cortex to restructure a hair's characterstics. The cortex is protected by the cuticle, which is a transparent layer of tiny, overlapping scales of keratin. When the hair is in good condition the keratin scales will be shiny and lie flat; if your hair is tangled, dry or damaged the scales will be ruffled, which will give your hair a dull appearance and a rough texture.

Hair Growth

The hair root is the fastest growing organ in the body; hair on the scalp grows at the rate of about one half inch a month. Hair does not grow at a constant rate. It grows faster in summer than in winter, and grows at different rates over the head. The growth rate for each person varies. The cycle, which is the time between the first growth of hair and its final shedding, generally lasts for between three to five years, but may go on much longer. When the cycle is over, the follicle shrinks and goes into a resting phase that lasts for a few months. The old hair stops getting longer and simply remains in the follicle until a new hair forms underneath and pushes it out.

The average person sheds about 100 hairs each day. Fortunately, the growth and resting cycles are not synchronized in adjacent follicles and you do not notice any obvious patches of hair loss. Some people find it difficult to grow their hair long, while others find it very easy. This is the result of your particular combination of growth rate and hair life span - only if your hair has a fast growth rate and a long life span can you quickly and successfully grow your hair long.

There are between 100,000 and 150,000 hairs growing on the head at any one time. Redheads have the least amount of strands but the thickest hair, while blondes have the most amount but the finest hair. This total number decreases as you get older, as some follicles wear out and are not replaced. The rate at which you lose hair is genetically determined an cannot be halted.