Types of Hair - Stages of Hair Growth

Kinds of Hair

Terminal Hair-This type of hair is much darker, usually coarser, and is represented on the limbs and trunk of the body. Terminal hair is different from scalp hair in that it grows at a much slower rate and is not clustered together in as dense patches as scalp hair. Primary terminal hair is typically seen on the eyebrows and eyelashes and of course, the scalp. Secondary terminal hair is seen in the pubic areas and the facial region of men as puberty approaches.

Vellus Hair-This is the short, usually fine and soft hair that is typically seen very faintly. This is the hair that is commonly referred to as down or fuzz on newborn infants. The most common sites for vellus hair on mature adults are on the forehead, ears and even the scalp, when normal scalp hairs have been lost due to the effects of balding.

Intermediate Hair- This type of hair is also commonly referred to as transitional hair by health care practitioners. Transitional or intermediate hair are those strands that are in the process of shifting from terminal hair to vellus hair and vice versa.

Hair Growth Phases

We must understand that we are all constantly in a state of growing and losing our hair. From the time we are conceived in the womb, our body is in a continuous, and changing, growth cycle.

Lanugo hair is commonly known as womb hair. This is the hair that begins to grow on the embryo approximately five months after conception. This hair is usually very light as no pigmentation has taken place as of yet. Lanugo hair is also commonly very soft and fine. Languo hair can grow to be quite long. It is generally shed just prior to delivery and is replaced with vellus hairs.

Puberty-Hair begins to grow in the genital regions as individuals advance in puberty. The hair that is grown during this period is referred to as secondary terminal hair and generally replaces the vellus hair that had been there since birth. This phase of hair growth is also what accounts for the development of beards and mustaches in young men as they approach puberty.

Everyday our scalp sheds hair that is dead, damaged and no longer useful. This occurs from the time we are infants in the cradle and continues throughout the remainder of our lives. The difference between the hair we lose as children and young adults and the problems that occur in other parts of our lives is that the hair we lose is not replaced by new growth.

One of the common trends that is seen as individuals advance in age and begin to lose primary terminal hairs on the scalp area is for it to be replaced with vellus hairs, very similar to what was present when the individual was first born as an infant before the scalp filled in with permanent hair.

While the human body is covered with hair from the top of our hairs to various other parts of our bodies, these hairs are actually much different in nature, growth and production. Some people may joke about transplanting hair that grows in abundance in less desirable regions of the body to balding areas on the scalp, but there is a very good scientific reason why this would not work. This would be ineffective, because the hairs are not the same type and do not grow in the same manner.

Hairs from different body parts of the same individual can vary greatly in color or pigmentation, length, level of tightness or curl and about twenty other characteristics that may be miniscule to the human eye but make a huge difference in how the final effect of the hair is developed and viewed.

Throughout most of our lives, our hair, regardless of where it is located on our body, is in one of three primary growth phases.

Phase One-Active Growth

The medical term for this phase is anagen and surprisingly, it generally lasts for years; sometimes up to six. This is the phase in which hair actually grows and is also the phase which is affected by the presence of DHT. As levels of DHT steadily increase, the length of the anagen phase progressively grows shorter. As a result of the shortened anagen phases, individuals notice that their hair is becoming finer and thinner with less color properties.

Hair grows at an average rate of about half a millimeter per day which is equal to half an inch per month. Of course, at times it can seem as though hair is growing much more rapidly or slowly depending upon your point of view at the time. Generally speaking, hair grows much faster in women than it does in men. The reasons for this phenomenon have not been firmly established, but it is believed that hormones present women are a contributing factor.

It may be difficult to believe, but most of our hair is in the anagen, active growth phase. Only a small percentage of our hair strands are in one of the two remaining phases of cyclical hair growth.

Phase Two-Regressive Phase

This phase is medically known as the catagen phase. On average on a typical day, most people shed anywhere between 75-100 scalp hairs. This generally occurs as a result of brushing ones hair and shampooing. This may sound like a lot, however; most people have an average of at least 100,000 hairs on their scalp at any given time. This phase lasts approximately two to three weeks.

Phase Three-Resting Phase

Referred to as telogen by medical practitioners, this is the phase where hair is resting or sleeping. This means that there is no active growth going on with that hair strand. It is neither growing nor falling out. Strands of hair only rest for a few months before they begin to fall out. The loss of hair may be precipitated by the beginning of a new active phase, when new hair begins to push up and as a result dislodges the old hair. Generally, this phase lasts for about three months.

Summary

The growth of human hair is an extremely complex process, based on a number of factors. Genes play a significant role in the growth and development of hair; however they cannot be 100% responsible for the final results in how hair is grown; because it has been historically observed that siblings with both the same mother and father frequently have drastically different types of hair. Other factors which contribute to the type of hair a person grows is based on environment and individual choices as well as medical conditions. Nutrition also plays a very important role in whether or not the body is able to produce healthy hair.

The average person has at least 100,000 to 150,000 strands of hair on their head. One single strand of hair is comprised of multiple, almost microscopic, components; all of which contribute to the bodys ability to grow and maintain healthy hair. The body produces three different types of hair; the hair type found on the human scalp is known as terminal hair.

Three phases are involved in order for hair to grow successfully. The active growth phase is known as anagen. The majority of all hairs strands are actively growing. The other two phases are known as the catagen and telogen phases. These are the regressive and resting phases; respectively. On any given day most people will lose at least 50 hairs. These hairs are in the catagen phase and are lost to make way for new growth hair that will soon appear. Hairs in the resting phase are neither growing nor falling out. They are simply sleeping.

How you lose or keep your hair depends on how wisely you choose your parents

Edward R. Nida

Next: Reasons for Hair Loss

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Types of Hair - Stages of Hair Growth