Understanding Your Hair
On average, an African-American scalp has roughly 60,000 hair follicles, an Asian scalp has somewhere around 75,000 follicles, and a Caucasian scalp has 100,000.
Every hair and hair follicle differs. Therefore, it is important to have a trusted hair transplant specialist responsible for assessing the overall plan for your hair transplant. Some hairs are more coarse and wavy, while others can be very fine and straight. Therefore, when hair is transplanted, it is very important to design the hair transplant pattern in a way that takes every point into consideration.
For patients with very coarse, thick, and wavy hair, it is not necessary to harvest and transplant as many hair follicles as a patient who has finer, straight hair would need. That is why the total amount of hair follicles varies based on ethnicity and hair type. This also means that it is to be taken into consideration when deciding how many grafts can “safely” be harvested from the donor area. If too many grafts are harvested from the donor area, it can make the scalp look thin in those areas. It is important to know that once the hair follicle is harvested and transplanted, that follicle is no longer in the area it was harvested from. That means that no hair will grow from the spot where the hair follicle used to be. The hair will now grow out of that follicle that is now moved to the recipient area.
The hormone called DHT (dihydrotestosterone) causes the miniaturization of hair and eventual hair loss due to androgenetic alopecia or male pattern hair loss. The hair follicles that are extracted from the donor areas are typically immune to the effects of DHT. Therefore, when they are transplanted into the recipient area, they become permanent hair in that new home. Medications such as finasteride are also used to “block” this hormone to help slow down hair loss.
It is also important to understand the growth cycle of hair follicles. The first stage is the anagen phase. This is the growth stage in the hair cycle, when hair will grow about 1 cm over the course of 28 days. The anagen phase will receive an unknown signal from the body, which will cause the follicle to go into the catagen phase.
The catagen phase is the transition time that occurs at the end of the anagen phase. This signals the end of the growth period for that hair and will last 2 to 3 weeks while that hair converts to a club hair. A club hair is formed when part of the hair follicle that is in contact with the lower portion of the hair becomes attached to the hair shaft. During this process that lasts about 2 weeks, the hair is cut off from both its blood supply and the cells that are responsible for producing new hair. Once the club hair is fully formed, the follicle will enter into the telogen phase.
The telogen phase is the resting phase for the follicle. When the body is under extreme stress, up to 70% of hair can prematurely enter into the telogen phase. Telogen effluvium is the condition where a noticeable amount of hair loss occurs. The final product of a hair follicle in the telogen phase is dead, fully keratinized hair. Up to 100 club hairs are shed on a daily basis.
This can all be simplified by understanding that anagen, catagen, and telogen are derived from the Greek prefixes ana, kata, and telos, meaning up, down, and end.