If you think your hair is falling out, you're right. That does not mean, however, you are going bald. Hair grows in a continuous cycle consisting of three phases: Anagen, catagen and telogen. The length of each of these phases is different for different people and for different parts of the body. Losing hair at the end of each cycle is part of the process. As long as hair follicles are healthy, new hair will replace hair that has fallen out.
Anagen
Anagen is the growth phase of hair growth. During this phase, the hair shaft is created and the hair follicle pushes deeper into the pore to receive nutrients. People who have long hair have long anagen growth phases. For most people, the anagen phase of head hair is much longer than the anagen phase of hair on other parts of the body, which is why head hair grows much longer than body hair, on average, about six inches per year. At any given time, the majority of your hair is in anagen phase, which can last anywhere between two and eight years.
Catagen
The catagen phase, transition, regression or renewal phase, occurs when the hair follicle degrades, but the hair shaft does not fall out. During this phase, hair follicles stop growing and begin to shrink, up to about one-sixth of the normal length. Eventually, the bulb of the follicle detaches from the blood supply, pushing the hair shaft up and out of the skin, eventually completely disintegrating. This phase lasts about two to four weeks and at any given time, only about 3 percent to 4 percent of body hair is in this phase.
Telogen
The telogen phase is also known as the resting phase. During this time the hair shaft is not growing, although a new one is beginning to form beneath. The old hair shaft begins to detach from the follicle, getting ready to fall out and be replaced by the new shaft. This phase lasts between five and six weeks or three to four months, and at any given time, approximately 10 to 15 percent of all hairs are in this phase. As with all cycles, once finished, the new hair shaft begins back at the anagen phase.
Hair Shedding
Hair shedding is a completely normal part of the hair regrowth process. It is sometimes referred to as the exogen stage. Typically, you will shed 100 strands of hair each and every day, as about 10 percent of your hair is in the resting phase of the cycle ready to fall out. Hair on your hairbrush or in your bathroom sink or shower is common. However, if handfuls of strands are lost when you comb your hair with your fingers, you should contact your doctor immediately. There are several causes of hair loss and some could indicate significant medical problems that require attention. Causes of excess hair loss include stress, vitamin deficiencies, trauma, chemical damage to the hair, thyroid problems, prescription drugs including chemotherapy, as well as hormonal imbalance.
Hair Length
The genetics of each cell type and location dictates the length of the anagen phase and whether hair will grow long or short. For example, your hair on your scalp may have an anagen phase lasting up to seven years or more. Hair on your eyebrows, however, may have an anagen phase that is only four tio seven months. Body hair on the arms and legs also will have a short anagen phase.
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