Glossary of Hair Loss and Hair Replacement Terms

Below, you’ll find a compiled list of common terms related to hair loss, hair loss treatments and hair replacement technologies.

5-alpha reductase (5α-reductase): The enzyme responsible for converting testosterone into Dihydrotestosterone (or DHT), the male sex hormone believed to be the main contributor in male pattern baldness.

Androgenetic alopecia: Male or female hair loss or pattern baldness that is not caused by disease or illness, but rather by a genetic predisposition.

Alopecia areata: Considered an autoimmune disease, alopecia areata appears to cause hair follicles to be under attack by the body’s immune system. Hair can be lost from some or all areas of the body, usually the scalp.

Anagen: The growing phase of hair which usually lasts from one to eight years.

Anagen Effluvium: Hair that is lost when it supposed to be in the anagen or “growing” phase. This generally occurs during chemotherapy or radiation treatments.

Anemia: A deficiency of red blood cells or low hemoglobin in the blood.

Anti-androgen: Anti-androgens such as Spironolactone blocks existing DHT from attaching to the hair follicles.

Autoimmune: An immune response that is misdirected, causing the immune system to attack the body itself.

B Complex Vitamins: Originally believed to be a single vitamin (Vitamin B), these have now been divided into several B vitamins.

BPH: Benign prostatic hyperplasia, or non-malignant enlargement of the prostate.

Clinical Trials: Trials performed to determine the safety and effectiveness of a medication or device by monitoring the effects on large numbers of people.

Cortisone: A naturally-occurring hormone produced by the adrenal cortex. Used as an anti-inflammatory in a variety of medical procedures.

Crown: The highest part or top of the head.

DHT or Dihydrotestosterone: An androgen or male sex hormone believed to be the primary contributing factor in male pattern baldness. Testosterone is converted into DHT by an enzyme called 5-alpha reductase. DHT acts on a hormone receptor in the hair follicle, after which hair growth is slowed, weaker hair is produced until finally the follicle stops growing hair entirely.

DHT Blockers: DHT blockers block the growth of Dihydrotestosterone (or DHT), believed to be the main culprit in male hair loss. The only FDA-approved DHT blocker is Finasteride (prescribed as Propecia® and used by men ONLY).

Donor Dominance: A term coined by hair transplant surgery pioneer Dr Norman Orentreich.  In hair transplant surgery terminology, this refers to the dominance of healthy, hair-bearing follicles when they are transplanted into the balding “receiving” areas of the scalp.

Donor site: The area from which pieces of hair-bearing skin are taken during a hair transplant.

FDA (Food and Drug Administration): A U.S. Public Health Agency that verifies the safety and effectiveness of prescription and over-the-counter drugs.

Finasteride: Made by Merck, Finasteride is the active ingredient in Propecia®, an FDA-approved DHT blocker and hair loss medication.

Follicular Miniaturization: The transformation of large, dark, strong hairs into fine, thin, sometimes colourless hair, which is attributed to some forms of hair loss.

Follicular Unit Extractuon (FUE): The procedure by which individual follicular units are removed from the donor area, rather than being removed as a strip.

Follicular Unit Transplantation (FUT): During hair transplantation, this is when the surgeon harvests hair in naturally occurring follicular units and grafts them to the balding sections of the scalp.

Frontal: Pertaining to the forehead. In hair loss terminology, refers mainly to receding hairlines.

Genetic: Having to do with genes and genetic information.

Hair Loss: Thinning of the hair on the scalp. The medical term for this is alopecia.

Hair piece: See hair system.

Hair system: A hair replacement piece that is attached to the head to cover bald spots and/or thinning areas. Often called a hair piece or, derisively by its more antiquated name, the toupee.

Heredity: Genes, chromosomes or genomes that are transmitted from parent to child.

Menopause: The period in women’s lives when menstruation ceases completely.

Mesotherapy: A procedure in which a cocktail of vitamins, minerals and/or DHT blockers are injected into the mesoderm (or layer of fat) just beneath the skin of the scalp.

Miniaturization or Follicular Miniaturization: See Follicular Miniaturization.

Minoxidil: A medication originally used orally to control severe hypertension, Minoxidil is a topical scalp application used to stop or slow hair loss and promote hair growth. Better known under its trade name, Rogaine®.

Oligomeric Proanthocyanidins (OPCs): A natural compound found in most fruits and vegetables, particularly in plant bark, skin and seeds. OPCs are used to treat vascular diseases and, in terms of hair loss, are believed to inhibit DHT production and increase blood circulation to the scalp.

Oxygenation: The process during which oxygen molecules enter the body tissue.

Propecia®: One of only two FDA-approved medications for hair loss. It is a prescription-only medication used by men only to block DHT from damaging hair follicles and causing hair loss.

Proscar®: A medication prescribed for treatment of enlarged prostate. Proscar contains Finasteride, the active ingredient in Propecia.

Rogaine®: The first over-the-counter medication to receive FDA approval as a topical medication used to slow or stop hair loss and promote hair regrowth. See Minoxidil.

Sebum: Oily secretions near the hair follicles that keep hair shiny and lubricated.

Topical: Related to the surface area of the skin or scalp.

Traction alopecia: Gradual hair loss that is caused primarily by pulling force being applied to the hair – for example, through tight braiding, ponytails or hair weaves.

Transplant: In hair loss, the transplanting of hair from the donor area to the balding area of the scalp.

Telogen Effluvium (TE): More common in women than men, this is hair loss caused by crash dieting, prolonged emotional or physical stress, post-pregnancy hormonal changes or severe illness.

Trichotillomania: Hair loss that results from compulsive hair pulling or twisting.

Vasodilator: A drug that causes dilation of the blood vessels.

Vellus hairs: Sometimes referred to as “peach fuzz,” vellus hairs are tiny, colorless hairs that are not influenced by hormones.

Ventilation: The method by which hair is attached to the base. When creating a hair piece, ventilation can be customized to accommodate the hair styles a user is most inclined to wear and the overall look the user is hoping to achieve.

Vertex baldness: Baldness that begins at the crown, or top of the head.