Hair Growth Cycle Explained - What are the Stages and Factors of Hair Growth

Hair loss may be concentrated at a certain stage. In addition to some external reasons, such as damage or pressure, it may also be caused by the replacement of the growth cycle. Hair growth cycle is composed of three or four distinct stages, each hair growth stage has its own timeline but can be varied for different people. Here we’ll go through all the four hair growth phases and factors that affect the cycle. 

Hair Growth Cycle Explained - What are Four Stages of Hair Growth

We lose hair on a daily basis, up to fifty to one hundred, some humans even have seasonal shedding, particularly in the autumn, therefore it's unsurprising that despite the hair being fundamentally dead, your natural hair does have a life cycle, the hair growing currently is not the same hair that you were born with. What growth stages does the hair experience? Let’s look at the hair growth cycle. In the hair growth cycle, there are four phases, anagen, catagen, telogen, and exogen. 

1. Anagen (period of active growth): the state in which hair actually grows, the rate of which is 0.5 inches per month on average, the amount of time a hair will remain in the anagen phase will vary from person to person, although scientists estimate between four to six years for your scalp hair, body hair is said to have shorter anagen phases. The anagen can be cut short through a number of factors such as stress and poor diet. 

2. Catagen (transitional phase): Once the anagen phase ends, the catagen phase begins. the catagen phase refers to the period of time in which the head attaches from the blood vessels and dermal papilla and the hair stops growing because the blood flow is removed depriving the follicles of much-needed oxygen and nutrients to actually grow the hair, this lasts for approximately 2-3 weeks and acts as a catalyst for the next phase.

3. Telogen (resting phase): the telogen phase where the hair follicle rests for approximately three months before starting the anagen phase again, in rare circumstances, people can suffer what is known as a telogen effluvium which is a noticeable thinning caused by long severe daily shedding periods and a longer telogen phase which may be a result of poor diet, stress, and deficiencies in vitamins and minerals or a combination of all of the above. At this point, the hair is being stable and not doing anything and it's just maintaining its function, but at some point, it's gonna break free and then shed, a new hair will grow in its position and the hair cycle will repeat, around 10% of the hairs on the body are in this telogen phase at any time.

4. Exogen (extension of telogen): usually after three months, the exigent phase will start. The exogen phase which is actually just an extension of the telogen phase is where the hair sheds and new hair simultaneously starts to grow and begin a new anagen period. Sometimes, people just mention the first three stages of hair growth. 

Hair Growth Factors - What Factors Affect the Hair Cycle?

It should be noted that the hair follicle exists below the skin, therefore trimming or shaving which are just acts of cutting hair to an arbitrary length will not change or affect the growth cycle of your hair, but plucking, waxing, or processing, on the other hand, will affect the growth cycle. If the problems become serious, be sure to see doctors and prepare some human hair wigs. 

Each stage of the hair cycle is regulated by signals from the scalp and the body. Certain signals instruct the dermal cells to begin producing hair and grow; these signals are known as growth factors and last up to the anagen phase, instructing the hair to grow; on the other hand, certain signals instruct the hair to die and fall out; these signals instruct the hair to enter the catagen phase and die; this process may repeat itself. 

For some people, the hair cycle lasts their entire lives, passing through a 6-year anagen phase before entering the catagen and telogen phases, where the hair falls out. However, there is a possibility that for others, as their lives change, the cycle shortens and the hair becomes thinner. The hair passes through all three phases normally, but the anagen phase is shorter.