The hair growth rates differ for scalp hair and for other body hair. Relatively, this is the main reason why scalp has the capability to grow much longer compared to other body hair.
Covering our entire body is almost five hundred hair follicles. If you are wondering where these hair follicles might be, a large percentage of them are actually invisible with the naked eye. And eventually, such hair growth rates are much shorter compared to other body hair, most especially too short to compare to the scalp hair.
Hair growth rates can be greatly determined by the growth phase of the hair growth cycle. The hair actually undergoes three phases: the anagen or the growth phase, the catagen or regressing phase, and the telogen or resting phase. As their names suggest, it is in the anagen phase that hair is actively capable of growing.
More or less eighty to ninety percent of the hair is in the anagen phase. During this phase, an average hair growth rate of one centimeter per twenty eight days, or about half inch per month happens. This could happen for almost one thousand days or around two to three years, and may even last for eight long years. This timeline is for the scalp hair. For other body hair, there is a considerable difference. Other body hair could continue to grow only within few months – nine months at most. Of course for vellus hair or the hair that cannot be seen by naked eye, hair growth rates might even be a lot shorter, truly unnoticeable in the case.
During the catagen phase, hair will stop growing. Major hair cells are dead, that is why. While scalp hair is under this phase for one to two weeks, other body hair might stay here for more than a week than that of scalp hair’s stay.
Lastly, the telogen phase is characterized by natural shedding of hair, fifty to one hundred strands per day on the average. This figure represents about eight to ten percent of the scalp hair. After this, hair re-grows back again to the first phase.