In brief, these hormones affect the hair growth cycle as follows:

1. High levels of the 5-alpha-reductase enzyme occur in some cells of the hair follicle and sebaceous glands.

2. 5-alpha-reductase converts testosterone into DHT.

3. DHT causes the terminal hairs to miniaturize.

4. This leaves short, soft, fluffy vellus hairs that provide inadequate scalp coverage.

5. The growth phases gradually become shorter until these hairs are lost for good.

Alopecia areata is thought to be an immune system disorder that causes follicles to stop producing hairs in patches on the

At best, sufferers may waste money on inappropriate 'wonder cures' or even legitimate treatments that unfortunately are not suitable for their particular needs. At worst, some people may be risking their health by self-prescribing powerful pharmaceutical drugs. I don't have a problem with hair loss sufferers saving money by purchasing cheap generic drugs on the internet, but I feel strongly that they should at least seek confirmation from their physician that a given drug matches their individual needs.

Before examining the most common causes of premature hair loss we need to understand that some shedding of hair is perfectly normal. Hairs grow from follicles that are tiny organs in the skin designed to grow a single hair that follows this repetitive cycle:

1. Lengthy growth period (Anagen Stage) - this phase usually lasts between two and seven years with an average growth rate of six inches (15cm) each year.

2. Short transition period (Catagen Stage) - this period of transition lasts for roughly two to four weeks. During this phase the hair shaft becomes detached and moves upwards within the follicle.

3. Resting period (Telogen Stage) - this phase lasts about three months allowing the hair to detach itself prior to falling out.

At this point a new hair begins to grow thus repeating the normal cycle of hair growth. Unfortunately a number of factors can interfere with the natural hair growth process leading to forms of hair thinning or premature baldness.

Androgenetic alopecia is the most common cause of hair loss, probably accounting for as much as 95% of pattern hair loss for both men and women. It is usually associated with aging and develops in predictable stages over varying periods of time. Each follicle follows a genetically programmed growth cycle with some follicles coded to remain active for a shorter time than others. This results in the development of the hereditary baldness patterns that are so familiar to us all.

For this type of baldness to occur, the following factors must be present:

1. A genetic predisposition for hair loss to occur (as explained above).

2. The presence of male hormones.

3. Aging - in other words, enough time for the first two factors to exert an influence.

All men and women produce male hormones such as testosterone and DHT. These have a useful role to play in both sexes but obviously occur in widely differing concentrations. It is the higher levels of androgens found in males that explains why this form of hair loss affects men more than women.

In brief, these hormones affect the hair growth cycle as follows:

1. High levels of the 5-alpha-reductase enzyme occur in some cells of the hair follicle and sebaceous glands.

2. 5-alpha-reductase converts testosterone into DHT.

3. DHT causes the terminal hairs to miniaturize.

4. This leaves short, soft, fluffy vellus hairs that provide inadequate scalp coverage.

5. The growth phases gradually become shorter until these hairs are lost for good.

Alopecia areata is thought to be an immune system disorder that causes follicles to stop producing hairs in patches on the h

Before examining the most common causes of premature hair loss we need to understand that some shedding of hair is perfectly normal. Hairs grow from follicles that are tiny organs in the skin designed to grow a single hair that follows this repetitive cycle:

1. Lengthy growth period (Anagen Stage) - this phase usually lasts between two and seven years with an average growth rate of six inches (15cm) each year.

2. Short transition period (Catagen Stage) - this period of transition lasts for roughly two to four weeks. During this phase the hair shaft becomes detached and moves upwards within the follicle.

3. Resting period (Telogen Stage) - this phase lasts about three months allowing the hair to detach itself prior to falling out.

At this point a new hair begins to grow thus repeating the normal cycle of hair growth. Unfortunately a number of factors can interfere with the natural hair growth process leading to forms of hair thinning or premature baldness.

Androgenetic alopecia is the most common cause of hair loss, probably accounting for as much as 95% of pattern hair loss for both men and women. It is usually associated with aging and develops in predictable stages over varying periods of time. Each follicle follows a genetically programmed growth cycle with some follicles coded to remain active for a shorter time than others. This results in the development of the hereditary baldness patterns that are so familiar to us all.

For this type of baldness to occur, the following factors must be present:

1. A genetic predisposition for hair loss to occur (as explained above).

2. The presence of male hormones.

3. Aging - in other words, enough time for the first two factors to exert an influence.

All men and women produce male hormones such as testosterone and DHT. These have a useful role to play in both sexes but obviously occur in widely differing concentrations. It is the higher levels of androgens found in males that explains why this form of hair loss affects men more than women.

In brief, these hormones affect the hair growth cycle as follows:

1. High levels of the 5-alpha-reductase enzyme occur in some cells of the hair follicle and sebaceous glands.

2. 5-alpha-reductase converts testosterone into DHT.

3. DHT causes the terminal hairs to miniaturize.

4. This leaves short, soft, fluffy vellus hairs that provide inadequate scalp coverage.

5. The growth phases gradually become shorter until these hairs are lost for good.

Alopecia areata is thought to be an immune system disorder that causes follicles to stop producing hairs in patches on the

At this point a new hair begins to grow thus repeating the normal cycle of hair growth. Unfortunately a number of factors can interfere with the natural hair growth process leading to forms of hair thinning or premature baldness.

Androgenetic alopecia is the most common cause of hair loss, probably accounting for as much as 95% of pattern hair loss for both men and women. It is usually associated with aging and develops in predictable stages over varying periods of time. Each follicle follows a genetically programmed growth cycle with some follicles coded to remain active for a shorter time than others. This results in the development of the hereditary baldness patterns that are so familiar to us all.

For this type of baldness to occur, the following factors must be present:

1. A genetic predisposition for hair loss to occur (as explained above).

2. The presence of male hormones.

3. Aging - in other words, enough time for the first two factors to exert an influence.

All men and women produce male hormones such as testosterone and DHT. These have a useful role to play in both sexes but obviously occur in widely differing concentrations. It is the higher levels of androgens found in males that explains why this form of hair loss affects men more than women.

In brief, these hormones affect the hair growth cycle as follows:

1. High levels of the 5-alpha-reductase enzyme occur in some cells of the hair follicle and sebaceous glands.

2. 5-alpha-reductase converts testosterone into DHT.

3. DHT causes the terminal hairs to miniaturize.

4. This leaves short, soft, fluffy vellus hairs that provide inadequate scalp coverage.

5. The growth phases gradually become shorter until these hairs are lost for good.

Alopecia areata is thought to be an immune system disorder that causes follicles to stop producing hairs in patches on the

For this type of baldness to occur, the following factors must be present:

1. A genetic predisposition for hair loss to occur (as explained above).

2. The presence of male hormones.

3. Aging - in other words, enough time for the first two factors to exert an influence.

All men and women produce male hormones such as testosterone and DHT. These have a useful role to play in both sexes but obviously occur in widely differing concentrations. It is the higher levels of androgens found in males that explains why this form of hair loss affects men more than women.

In brief, these hormones affect the hair growth cycle as follows:

1. High levels of the 5-alpha-reductase enzyme occur in some cells of the hair follicle and sebaceous glands.

2. 5-alpha-reductase converts testosterone into DHT.

3. DHT causes the terminal hairs to miniaturize.

4. This leaves short, soft, fluffy vellus hairs that provide inadequate scalp coverage.

5. The growth phases gradually become shorter until these hairs are lost for good.

Alopecia areata is thought to be an immune system disorder that causes follicles to stop producing hairs in patches on the

In brief, these hormones affect the hair growth cycle as follows:

1. High levels of the 5-alpha-reductase enzyme occur in some cells of the hair follicle and sebaceous glands.

2. 5-alpha-reductase converts testosterone into DHT.

3. DHT causes the terminal hairs to miniaturize.

4. This leaves short, soft, fluffy vellus hairs that provide inadequate scalp coverage.

5. The growth phases gradually become shorter until these hairs are lost for good.

Alopecia areata is thought to be an immune system disorder that causes follicles to stop producing hairs in patches on the head. In severe cases it can advance to the stage where all hair on the head is lost (alopecia totalis) or even a complete absence of body hair results (alopecia universalis).

In most cases the hair will reappear on its own but until then, the condition can be very distressing to sufferers particularly as its cause can be difficult to determine. If you feel you may be suffering from this form of hair loss, seek the advice of your physician who will carry out a physical examination and conduct blood tests to help determine the cause.

Telogen effluvium is characterized by a general thinning or shedding of hair over a period of months and is most commonly found in people who have recently experienced trauma. Common causes include childbirth, major surgery, severe illness, psychological stress and chemotherapy. The good news is that the abnormal growth behavior associated with telogen effluvium is temporary and reversible.

There are numerous other less common hair loss causes that need to be discounted before a course of treatment is chosen. Traction alopecia is the loss of hair from constant pulling, usually as the result of hair styling. Broken hairs can result in thinning, often caused by excessive styling or exposure to chemicals and sun. Finally, severe illnesses or nutritional deficiencies can cause side effects that may include degrees of hair loss.

I hope this brief article has gotten across the message that diagnosing the real causes of hair loss is not always a straightforward process. Once you and your physician have identified a cause, then you can work towards restoring your hair to its former glory. And the good news is, most forms of hair loss can be treated successfully. The next article in this series will look at some of the best hair loss treatments currently available.