How Hair Grows
It all starts with your hair follicles, which are living sacs of skin tissue buried deep beneath your scalp out of which hair starts to grow in groupings of 1 to 4 hairs. For 2 - 8 years at a time, your follicles are working continuously, growing hair, and pushing it up and through your scalp at a rate of about a half-inch per month. Eventually, each follicle enters a resting stage and its hair stops growing. Finally, the hair is shed from the follicle, as hair itself is not living, and allows a new one to spring up in its place and start the cycle all over again.
Shaft of hair: made of dead cells that have more regenerative properties.
Sebaceous Gland: lubricates and adds shine to the hair.
Hair Follicle: The sac from which your hair grows. It determines the characteristics of your hair (straight or curly, thick or thin, dry or oily).
Papilla (root): Bottom portion of the follicle that contains the blood supply.
Blood Vessels and Capillaries: nourish the root of the hair and feed the papilla.
Life Cycle of Normal Hair Growth
Anagen Phase: When the hair is actually growing
Catagen Phase: A short transition stage (2-4 weeks) when hair stops growing
Telogen Phase: When the hair is resting. At the end of the telogen stage, the hair shaft falls out and a new strand starts to grow in its place.
At any given time, 85% to 90% of your hair is actively growing. A normal, healthy head of hair has 100,000 hairs growing.
