What is normal hair loss and excessive hair loss?

In the daily course of our lives, we lose hair through everyday actions such as washing, combing, and brushing. Many people find this is cause for concern as they do not understand the process of hair growth and hence do not know when and if they should worry about their hair fall. Here is some help in understanding what hair fall you should expect and what is more.

The average human head has around 100,000 hair follicles. On average, blondes have the highest density of hair: 140,000 hair follicles, redheads the lowest at 90,000 follicles, and those with black hair have on average 110,000 follicles.

Human hair follicles are perhaps the only organs that actually grow in a specific cycle. In this cycle, our hair goes through three stages:

  • Anagen: This is the growing stage of human hair. It lasts anywhere from 2 to 5 years and as much as 85-90% of our hair is usually in this phase. Some people cannot grow the hair past shoulder length, others can grow their hair down to their ankles. The length of your anagen cycle limits the length to which you could grow your hair.
  • Catagen: After the anagen phase, our hair enters into the catagen phase, which is a small regression phase. It is kind of a transition stage between the anagen and telogen phases. This phase lasts around 2-3 weeks and about 1% of hair is at anytime in this phase.
  • Telogen: This is the last and resting phase of human hair. At any given time, 10-15% of hair is in this phase, which can last around 3-4 months. In this phase the hair is just sitting on your body and basically waiting to fall out.

It is normal to lose hair through our daily hair care, but what is "normal" varies from person to person, and therefore so does what is "excessive". The denser your hair, and the shorter your anagen cycle the more hair you will normally lose per day. For example, suppose that you hair is blond and your average anagen + catagen + telogen cycle lasts 3 years. That means every year about 47,000 hairs are replaced (140,000/3). That is equivalent to losing an average of 127 hairs per day normally . Or suppose you are a redhead, and your anagen+catagen+telogen cycle lasts 5 years, that would mean that on average you lose 90,000/(5*365), or about 50 hairs per day. Thus while losing 130 hairs a day regularly may be normal for one person, it could be excessive for another.

Obviously, there is no way to actually count how many strands of hair you lose everyday. Nevertheless, your daily hair care routine cannot be the cause of excessive hair loss and if you are experiencing excessive hair loss, it will be because of some other underlying causes such as genetics, medications, etc.

Excessive hair loss over a long period is is called alopecia. Baldness in men (Androgenetic alopecia) is very common and is also known as male pattern hair loss or baldness. A human body is programmed to produce an enzyme know as 5 alpha reductase. When the Androgen hormone in the scalp produces testosterone which mixes with 5 alpha reductase, it produces Dihydrotestosterone, or DHT. DHT is not well received by male (and female) hair follicles, cutting off blood supply, which is critical to growth of new hair. Thinning hair and or balding process begins when this occurs. Male pattern hair loss is more common as male bodies produce a higher quantity of testosterone.