Hair is a specialized keratinized thread develops from the scalp in strands of one to four groups and sometimes five or six also. They (hair follicles) are arranged as groups and called follicular units.

About 90 percent terminal hairs of a person are growing actively at a given time. The growth phase of a hair is divided into two distinct phases. However, one of the two phases namely known as Anagen is categorized as the actively growing phase and its lasts for two to seven years even though the average lasting period is about three years.  In this growing phase, the average growth rate of scalp hair is 0.44 millimeter a day, and as calculations say it is around 1/2 inch per month. The other phase known as Telogen is categorized by a state where the remaining 10 percent of scalp hairs are not growing and in a resting condition. This phase lasts for three to five months. The growth is stopped in the resting phase followed by detachment of the bulb from the papilla. New shafts start growing after succession of older shafts.

Follicular units are the groups from where hairs grow and these units are composed of two types of hair namely the terminal hair and the vellus hair. The smaller, shorter and finer traits of the vellus hair differs it from the terminal hair in the follicular unit. Pulling of the small black bulb, if a hair falls out naturally, it causes pain if it is in a growing state followed by swelling of a white and sticky section at the bottom of the hair shaft. People generally have a wrong concept that this may be the growth center and putting such constrain will stop the hair to grow again.

The dermal papillae and the actual growth center located near the hair shaft and the sebaceous gland are found tightly in place even after hair loss. Division and maturation of these cells cause growth of new hairs at that location within a month. The average loss of hairs in human is 100 per day and the first indication of abnormal hair loss is when we find them on comb or in sinks, tubs etc. Most of us generally have pattern baldness as well as thinning facade on the scalp in our family history which makes us concern whether we are the victim of hair loss for genetic reasons.  Even though, we might frequently notice hair in the drain, but in case one of us are not balding or suffering from thinning hair then we might never pay heed to it.