Hair follicles function with repeated cycles of growth and each cycle can be broken down into three distinct phases – Anagen, Catagen and Telogen. Every single strand of hair on your scalp undergoes these three phases in each cycle and is completely independent of the other
strands of hair on your scalp.
This phase is also called the active phase or the growth phase of your hair. At least 85 percent of all the strands of hair on the scalp are in this stage at any given time.
The anagen phase is much longer than you might expect and runs anywhere between two and six years.
Hair roughly grows 10 centimeters every year on an average while the rate of growth can vary from person to person. In any case, the total length of a single strand of hair is unlikely to grow after reaching the length of one meter. During this stage, the cells in the hair root are dividing at a rapid pace and new hair is formed quickly. The newly formed hair pushes the club hair up and out of the follicle. In simple terms, club hair can be defined as specific strands of hair
that have already passed the anagen phase. During this phase, your hair can grow about one centimeter every 28 days and remains active for several years.
Some people find it easier to grow their hair longer than others because of their lengthened active growth phase. The duration of the active phase of growth can decide how long your hair can be grown.
The hair on your arms, legs, eyebrows and eyelashes have very short spurts of growth, lasting between 30 to 45 days. This is the reason why your body hair is never as long as your scalp.
This phase is a transitional period between the growth and resting. Roughly three percent of your scalp hair is at this stage at a time, lasting between two and three weeks at a time. After the growth stops, the sheath in the outer root shrinks, attaching itself to the root
of your hair. This process is known as the formation of the club hair. During this phase, the hair follicle shrinks to 1/6th of its normal length and lower part of the hair is destroyed. The catagen phase also sees the breakage of dermal papilla, resting below on the surface of
The Telogen phase is known as the resting phase. Roughly six to eight percent of all the hair on your scalp is at this stage at the same time. The Telogen phase lasts for about 100 days on the scalp. For body hair like eyelashes, eyebrows, arms and legs, the phase is much longer.
During the Telogen phase, hair follicles are at complete rest while the club hair is formed completely. When you pull out a hair at this stage, you will notice a dry, hard and solid white material at its root. The Telogen phase also accounts for the normal hair fall. Roughly 25 to 100 strands of hair that are in this phase are shed every day and this is no reason for alarm.
During the Telogen phase, your hair stops growing, but remains attached to your hair follicle. The dermal papilla is also in place during the resting phase. When the Telogen phase approaches its end, a new anagen phase begins the next cycle.
The base of your hair follicle and dermal papilla rejoin and a new hair begins to form and grow. If the old hair in the same place has not already been shed, the new growing hair pushes it out, beginning the next growth cycle.