Hair Loss Glossary and Definitions

5 Alpha Reductase

5 Alpha Reductase is an enzyme which converts testosterone to dihydrotestosterone (DHT) which is the hormone that triggers Androgenetic Alopecia in individuals who are genetically susceptible.

Alopecia

Alopecia Areata: Hair loss which occurs in patches on the scalp.

Alopecia Totalis: Hair loss which occurs over the entire scalp.

Alopecia Universalis: Hair loss which occurs over the entire body.

Androgenetic Alopecia - Genetic hair loss caused by DHT.

Traction Alopecia
This refers to hair loss which occurs do to traction place on hair. Traction alopecia is commonly seen with braids, pony tails and other hairstyles which create traction on the scalp.

Dermal Papilla

The dermal papilla is situated at the base of the hair follicle. The dermal papilla contains nerves and blood vessels which supply glucose for energy and amino acids to make keratin.

DHT (Dihydrotestosterone)

DHT is a male hormone that is suggested to be the main cause for the shrinking of the hair follicle and for hair loss. DHT is formed when the male hormone testosterone interacts with the enzyme 5-alpha reductase.

Donor Area

The donor area is the extracted scalp removed from the back of the head which is then divided into grafts or follicular units for implantion into the recipient area. The donor area usually consists of the back of the head but can also include the sides is some cases.

Grafts are taken from this donor area because they retain their resistance to dht even after they are implanted.

Finasteride

Finasteride is the generic name of the brand name drug Proscar. Proscar is manufactured by Merck and is FDA approved for the treatment of benign prostate enlargement. One milligram tablets of finasteride have been marketed under the brand name Propecia as a treatment for hair loss.

Hair Grafts

Not all hair grafts are the same and you should get to know the difference and the best one to have for your hair transplant procedure.

Follicular Unit Grafts - The most popular, widely used and generally accepted best type of hair grafts are follicular units. Hairs on your scalp grow naturally in 1 to 3 hair groups in a single unit. These follicular units are left intact when they are implanted in the recipient area. Since they are left in their natural state of 1-3 hairs, they look more natural and undetectable.

Micro Grafts - are 1-3 hair grafts that are NOT in the follicular unit group. Although they contain roughly the same amount of hairs, micro grafts are 1, 2 or 3 hairs that are not growing together as part of a single follicular unit.

Mini Grafts - Small mini grafts consist of 3 to 5 hairs into a small recipient site and large mini grafts are 5 to 7 hairs into a small round recipient site.

Maxi Grafts - Grafts consisting of approximately 6-8 hairs in a single graft.

Hair Plugs - Grafts consisting of 10-50 hairs each. Hair Plugs are seldom used anymore and you would be hard pressed to find a hair transplant doctor anywhere in the country that will give you a "hair plug."

Strips grafts - as the name suggests, are long strips of hair bearing skin. Seldom used.

Small slit grafts - 3 to 4 hairs into a slit recipient site.

Large slit grafts - 5 to 7 hairs into a slit recipient site.

Hair Growth Cycle

Hair follicles grow in repeated cycles. One cycle can be broken down into three phases.

1) Anagen - Growth Phase Approximately 85% of all hairs are in the growing phase at any one time. The Anagen phase or growth phase can vary from two to six years. Hair grows approximately 10cm per year and any individual hair is unlikely to grow more than one meter long.
2) Catagen - Transitional phase At the end of the Anagen phase the hairs enters into a Catagen phase which lasts about one or two weeks, during the Catagen phase the hair follicle shrinks to about 1/6 of the normal length. The lower part is destroyed and the dermal papilla breaks away to rest below.
3) Telogen - Resting Phase The resting phase follows the catagen phase and normally lasts about 5-6 weeks. During this time the hair does not grow but stays attached to the follicle while the dermal papilla stays in a resting phase below. Approximately 10-15 percent of all hairs are in this phase at an one time. At the end of the Telogen phase the hair follicle re-enters the Anagen phase. The dermal papilla and the base of the follicle join together again and a new hair begins to form. If the old hair has not already been shed the new hair pushes the old one out and the growth cycle starts all over again.

Each hair passes through the phases independent of the neighboring hairs.

Keratin: is a highly fibrous protein that is the primary material in the cells of the skin, hair and nails.

Mega Session Transplantation

Hair transplant procedures in which a large number of grafts are transplanted in one session. Typically 1,500 to 3,000.

Minoxidil

Minoxidil is the generic name of the brand name drug Rogaine. Rogaine is manufactured by Upjohn and is FDA approved for the treatment hair loss. Minoxidil is available in the form of a topical lotion with varying strength from 2% to 5%. Minoxidil was the first drug to be approved by the FDA for the treatment of androgenetic alopecia. It requires twice a day application and is not very effective on replacing frontal hair.