Hair Facts and Hair Loss Basics

Hair is the fastest growing tissue of the body, made up of proteins called keratins. Every strand of hair is made up of three layers: the inner layer or medulla (only present in thick hairs); the middle layer or cortex, which determines the strength, texture, and color of hair; and the cuticle, which protects the cortex. Hair grows from roots, which are enclosed in follicles. Below this is a layer of skin called the dermal papilla, which is fed by the bloodstream carrying nourishments vital to the growth of hair. Only the roots of hair are actually alive, while the visible part of hair is dead tissue, and therefore unable to heal itself. It is vital then to take care of the scalp and body in order to perpetuate hair growth and maintenance. Expensive treatments that claim to treat the visible hair and nourish it therefore are usually no more than bogus claims made to sell products.

 Hormones called androgens, usually testosterone, can cause hair follicles to shrink, causing thinning of hair or eventual hair loss. Reportedly only bone marrow grows faster in our body than hair does. The average scalp contains 100,000-150,000 hair follicles and hairs, with 90% growing and 10% resting at any given time. Hair actually grows in three stages: anagen, catagen, and telogen. The anagen phase is the phase where hair is actively growing, and of course this phase is longer for follicles in the scalp than anywhere else on your body, and lasts longer for women than men. It is natural for follicles to atrophy and hair to fall out, and this is called the catagen phase. This phase is only temporary, and eventually the follicle enters the telogen phase where it is resting. These are the 10% at rest mentioned above. Normal anagen phases last approximately five years, with catagen phases lasting about three weeks, and telogen phases lasting approximately 12 weeks. As you see it is natural to lose some hair. Natural hair loss is considered to be in the range of 100 hairs per day. It is not apparent to most people that hair is actually being lost until more than 50% of a person’s hair is actually lost.

Although both men and women can suffer significant hair loss, over 50% of men will suffer with Male Pattern Baldness (MPB), also known as androgenetic alopecia, at some point in their lives.  The reason behind hair loss is a genetically inherited sensitivity to Dihydrotestosterone (DHT) and 5-alpha-reductase. The enzyme 5-alpha-reductase converts testosterone, a male hormone, to DHT, the substance identified as the end-cause for hair loss.

Most hair loss follows a pattern that has been codified in a table called the Norwood Scale (see figure 1). There are seven patterns of hair identified in the Norwood Scale, Norwood I being a normal head of hair with no visible hair loss, Norwood II showing the hair receding in a wedge-shaped pattern. Norwood III shows the same receding pattern as Norwood II, except the hairline has receded deeper into the frontal area and the temporal area. Type IV on the Norwood Scale indicates a hairline that has receded more dramatically in the frontal region and temporal area. Additionally there is a balding area at the very top center of the head, but there is a bridge of hair remaining between that region and the front. Type V on the Norwood Scale shows that very same bridge between the frontal region and the top center, also called the vertex, beginning to thin. Type VI on the Norwood Scale indicates that the bridge between the frontal region and the vertex has disappeared. Finally, Type VII on the Norwood Scale shows hair receding all the way back to the base of the head and the sides just above the ears. Norwood patterns are determined genetically. 

 Hair loss has been noticed and studied throughout the ages, and some interesting discoveries were made in ancient times. For one it was noticed that eunuchs: those males without genitals-never went bald. Men who were castrated as a result of accidents in battle also never went bald. This was the first indication that testosterone had something to do with hair loss. It has also been found that the more recessive the hair gene, the more propensity toward baldness one has. Blond-haired persons have a greater propensity toward hair loss than darker-haired people, and therefore Caucasian persons have a greater propensity toward hair loss than non-Caucasian people. Beyond the genetic propensity of certain people toward hair loss, there seems to be various dietary triggers that activate the process, a notion that is promising since this can be controlled.

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