Glossary of terms used on this site

Lower bulb-shaped part of the hair.

is the outer covering of the hair shaft.

each hair goes through a continuous cycle that has phases of varying duration (anagen phase, catagen phase, telogen phase)

term referring to the number of follicular units per square centimetre

the hair follicle is a hollow segment of the epidermis that extends downwards to the dermis. The follicle is a thin bag made of epidermal tissue that’s bulb-shaped at its lower part. Hair follicles produce hairs. Each follicle is fed by a papilla.(The papilla of a hair follicle is an indentation at the base of the bulb of the hair. It contains many blood vessels that supply nutrients to nourish the growing hair.)

there are 20 to 30 cycles during a lifespan. Each cycle will last 3 to 5 years on average.

normally 45 to 60 hairs are shed daily and continuously renew themselves. Normal hair loss predominates at the end of summer and in springtime. Hair loss exceeding 60 hairs per day is considered to be excessive.

unit of measure for hair density incorporating the number of hairs per square centimetre as well as the hairs’ diameter.

a condition inherited from the parents or ancestors.