This video covers the four phases of the hair growth cycle in detail and explains what to expect in each.
We shed hairs on a regular basis as many as 50-100 per day so it should come as no surprise that despite being intrinsically dead, hair has a life cycle. The hair growing currently is not the same hair you were born with. In fact, like many mammals, Humans even have seasonal shedding particularly in the Autumn according to Swedish researchers.
Before we continue - 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. Plucking, waxing or threading, however, will affect this growth cycle.
In the hair growth cycle, there are four states, Anagen, Catagen, Telogen, and Exogen.
Anagen is the state in which hair actually grows, the rate of which is 0.5 inches per month on average. The amount of timer a hair will remain in the anagen phase will vary from person to person although scientists estimate between 4-6 years for scalp hair. Body hair is said to have shorter anagen phases. The anagen phase is particularly interesting depending on the type of follicle you are studying. In men and women with androgenic alopecia, the hormone Dihydrotestosterone shortens the anagen phase and miniaturizes the follicles on the vertex of the scalp whereas androgenic hair such as chest hair and beards are dependent upon Dihydrotestosterone to grow. The anagen phase can also be cut short through a number of factors including stress, poor diet, and ageing. Once the Anagen Phase Ends the Catagen Phase Begins
The Catagen phase refers to the period of time in which the hair detaches from the blood vessels and dermal papilla and the hair stops growing as the blood flow is removed depriving the follicle of much-needed oxygen and nutrients to grow the hair. This lasts for approximately two weeks and acts as a catalyst for the next phase - Telogen
The Telogen phase is where the follicle rests for approximately 3 months before starting the Anagen phase again. In rare circumstances, people can suffer what is known as Telogen Effluvium which is the noticeable thinning caused by long severe daily shedding periods and a longer telogen phase which may be a result of poor diet, stress, deficiencies in vitamins and minerals or a combination of all of the above. However usually after three months, the Exogen 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. As mentioned previously you can shed up to 100 hairs a day and not even notice. You are probably wondering why you aren’t going completely bald every few years for a three month period - Well each hair follicle is a complex mini organ that has its own biological clock and is independent so whilst some will be synchronized simply by coincidence it would be incredibly rare for all to synchronize completely.
As stated previously shedding is an ongoing process and may be seasonal and indeed even gender dependent as Research suggests that women experience slightly higher rates of telogen than Men do during July, which sees the telogen hairs falling out over 3 months later, in mid-October or November. The reason for this is unclear, but some suggest that the summer heat may provide some explanation.
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22 авг 2024