Why do your hair grow faster in the summer ?
Most of the research states that hair growth is not seasonal and in fact, hair grows about 6 inches per year, which is approximately .3-.4mm/day. There are three stages of growth and shedding--anagen, catagen and telogen. Anagen is the phase in which the cells in the hair roots are dividing rapidly. This is an active phase and results in a new hair. This pushes the club hair which is a hair that is no longer growing up and out of the follicle. Hair on the scalp will stay in this phase from 2-6 years, and depending on the length of the active phase that a person has, this will determine how long they can grow their hair. The catagen phase occurs over a 2-3 week period and hair growth ceases. The outer root sheath shrinks, attaches to the root and forms a club hair. The telogen phase is a resting phase and lasts about 100 days for scalp hair. The follicle is resting, a club hair is completely formed. All three phases described occur simultanteously, with one hair being in the anagenic phase, and another in the telogenic phase. Although diet and exercise may affect hair growth, the seasons do not affect the growth rate of hair.