Hairs grow from follicles on the scalp. Depending on your genetic makeup, your scalp can have between 90,000 and 150,000 follicles. The production of hair occurs in three different phases: anagen, catagen, telogen.
The phases run simultaneously so some hairs on your head will be in the Anagen phase and others in Telogen. For each hair strand, the Anagen phase should start again once the Telogen phase is complete, but some people may experience longer Telogen phases meaning hair is shedding but no new hair is growing.
This may result in thinning of the hair. In this case, the goal is to, effectively, nourish and support the Anagen phase and encourage the growth phase to begin.
The speed at which your hair grows depends on both genetics and the shape of your follicles.
According to the US Center for Disease Control, hair grows at an average of 0.50 inches (1.25cm) per month. This means the average person can expect to grow 6 inches (15.24 cm) of hair per year, which sounds like a lot, right? So why does it never feel like it?
Well, things like poor diet, over-styling and not taking good care of your hair can result in split ends and breakages which shorten the length of your hair.