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HSC Hair Loss and Hair Restoration Glossary

The medical term for hair loss. This may be the result of hereditary disposition, illness, or functional disorder.

Alopecia Areata
An autoimmune disease that causes the body to form antibodies against its own hair follicles. It usually begins with the sudden loss of hair in smooth, circular patches on the scalp.

The phase when hair grows, usually about 1/3 of an inch a month, and lasting up to seven years.

Androgenetic Alopecia
Classic male pattern baldness, hereditary in nature, and the most common type of hair loss in men. It follows a gradual loss pattern that usually begins in the temple and crown areas and may progress to leave a “U” shape hair extending from the ears across the back of the scalp.

Anterior Scalp

Front of the head.

An image- and algorithm-guided robotic system, employed during a transplant by a physician during a hair transplant procedure, to make the best selection of follicular units for each individual. Dr. James Harris was the lead consulting physician on the invention of the ARTAS™ robotic system, wherein the follicular unit excision (FUE) process―based on the patented Harris S.A.F.E. System™―enables trained physicians to harvest units more rapidly and with significantly lower transection rates than with traditional methods.

A bone, tissue or hair graft taken from your own body.

Club Hair
A hair that has completed its growing (anagen) phase and has entered the resting (telogen) phase, and has therefore stopped growing. It will eventually be pushed out and replaced by a new growing hair.

Old-fashioned “plugs” rarely heal flush with the skin and therefore leave the scalp with lumps that resemble tiny cobblestones. The most common way to remedy this situation is by removing the old plug completely.

The layer of the hair shaft that surrounds the medulla, and accounts for the majority of the hairs’ size and strength.

The portion of the scalp that is associated with the vertical surface in the back of the head.

The outer surface of a hair strand, It is composed of colorless keratin protein which gives hair its shine and protects it from harsh elements.


A technique utilizing high-power magnification on a prospective transplant candidate that measures hair density, follicular unit composition and degree of miniaturization. It is used to help evaluate a patient’s candidacy for hair transplantation and predict future hair loss.

Dermal Papillae
The uppermost layer of the skin, that plays a pivotal role in hair formation and growth. This layer contains nerves and blood vessels which supply glucose for energy and amino acids to make keratin.

The layers of cells that form skin. The middle layer contains the bulk of the hair follicle.

Dihydrotestosterone (DHT)
A male hormone that may be the main cause of male pattern baldness, that results from the miniaturization of hair follicles.

Donor Site
The areas of skin used to take healthy hair for transplant to balding areas. The donor site must not be subject to the effects of the hormone DHT, but must contain healthy, permanent hair, generally found on the back and sides of the head.

Female Pattern Baldness (FPB)
A hereditary pattern of baldness found in women typically characterized by a diffuse and progressive thinning of the hair throughout the entire head of a woman. Causes include genes, age and hormones.

The generic name of the brand name drugs Propecia® and Proscar®, used to treat hair loss. Available only by prescription, the medication is for men and is orally administered. This medication is a DHT II (dihydrotestosterone II) blocker and decreases the influence of DHT II on male pattern baldness. Research has indicated that approximately 65% of men who take this medication consistently, will experience a reduction in hair loss and even re-growth of miniaturized hair.

The structure in the scalp that grows hair.

Follicular Unit
Natural groupings of hair follicles that grow together and share the same blood supply. The follicular unit of the adult human scalp usually consists of 1-4 hair follicles.

Follicular Unit Dissection
A hair transplant technique in which individual follicular units are dissected from a strip of donor skin and hair tissue, utilizing a stereo-microscope of approximately 10x magnification to precisely isolate the follicular unit grafts. This technique subjects the follicular units to the least possible risk of damage.

Follicular Unit Excision (FUE)
A state-of-the-art method of obtaining follicular units from the donor area one-by-one using the ARTAS™ Robot or the Harris S.A.F.E. System invented and patented by Dr. James Harris of Hair Sciences of Colorado, and currently used around the world. Because the amount of skin tissue obtained to extract a single follicular unit is very small, the procedure is minimally invasive. The “taking” part of the entire “take and plant” procedure that makes up Follicular Unit Transplantation.

Follicular Unit Strip method (FUS)

This is a method of obtaining grafts from the donor area whereby a strip of skin is removed from the donor area under local anesthesia. The donor site incision is sutured closed and follicular unit grafts are dissected free from the strip using stereomicroscopic dissection. The only evidence of surgery is a thin, horizontal line hidden under the hair on the back or side of the head. 

Follicular Unit Transplantation (FUT)
See Follicular Unit Hair Transplantation (FUHT)

Follicular Unit Hair Transplantation (FUHT)

A hair transplantation technique in which the surgeon harvests hair in naturally occurring follicular units, either with the FUE or strip harvest technique, and places them in the bald or thinning sections of the scalp. The “planting” part of the entire “take and plant” procedure that makes up Follicular Unit Transplantation. Results are natural and undetectable.

Frontal Alopecia

Hair loss at the front of the head

Gene Therapy
A hair loss treatment method that seeks to manipulate an individual’s genetic makeup to prevent hair loss. Recent advances show promise that this could be a reality within a decade or so.

Golden Follicle Award

An award presented to one hair restoration physician annually by the International Society of Hair Restoration Surgery, the most prominent hair restoration professional organization in the world. The award “honors a member who has made outstanding and significant clinical contributions related to the field of hair restoration surgery.” Dr. James Harris was the 2014 recipient.

Graft Excision
A repair technique used to improve the appearance of poorly done hair transplants. Improperly positioned grafts are removed, divided into smaller units and then re-implanted in a more natural distribution and direction.

Follicular units transplanted into bald or thin areas of the scalp.

A patented device that measures the degree of hair growth or loss over a period of time. The technique is accurate and objective. It measures the cross sectional area of a bundle of hair in three specific regions of the scalp and provides a number, the Hair Mass Index (HMI), that can be compared from one year to the next.

Hair Density

The number of hairs in a defined area of the scalp. The average hair density on a male scalp is approximately 700-1000 hairs per square inch.

Hair Matters™
Dr. Harris’ blog about hair loss and restoration, with updates and insights straight from the source.

Hair Shaft
The part of the hair that projects out from the skin.

Hair Replacement Client’s Bill of Rights

Dr. Harris is committed to patient education and advocacy in the field of hair transplantation. To that end he has drawn up a Bill of Rights to help you understand what you should expect from a hair restoration provider. Learn more about the Hair Replacement Client’s Bill of Rights.

Hair Weaving
A process of lengthening or thickening hair by attaching hair that is not one’s own (synthetic or human) to existing hair on the scalp through braiding or other processes. The potential downside of this technique is that it can pull fine or thin existing hair from the scalp leading to permanent hair loss.

Harris S.A.F.E™ System™
An innovative, proprietary technology invented and patented by Dr. James Harris and now used by hair transplant physicians around the world. This breakthrough technology enables Dr. Harris to perform precise follicular excision without unnecessary follicular damage and the resulting loss that is often associated with traditional FUE techniques.  S.A.F.E™ stands for Surgically Advanced Follicular Excision. The S.A.F.E. Hex dissection tip improves on the existing methodology for FUE (Follicular Unit Excision). Dr. Harris won the prestigious Golden Follicle Award in 2014, awarded to one hair surgeon annually throughout the world, due in part to this groundbreaking invention. 


A tough, fibrous protein that is a key structural material of skin, hair and finger nails.

Laser Therapy
A low-level laser light treatment that in some studies seems to promote hair growth, slow hair loss and give hair a healthier appearance for both men and women. Light from the laser beam helps prevent or in some cases stop hair loss by increasing the metabolism of the follicles and stimulating protein production. The FDA has cleared laser therapy in the form of a helmet for at-home use.

Ludwig Scale or Ludwig Classification
The Ludwig Scale illustrates the common genetic pattern of female pattern baldness, from Mild (type 1), to Moderate (type II) and Extensive (type III).

Male Pattern Baldness (MPB)
The general-use name for androgenetic alopecia, the most common type of hair loss in men. It is caused by hormones, genes and age, and is usually progressive in nature. It affects the central and frontal area of the scalp and often results in a pronounced U-Shape configuration of hair on the sides and back.

A very small hair graft consisting of one or two hairs.


Region between the frontal scalp and the crown

The destructive process by which the male hormone dihydrotestosterone shrinks hair follicles.

A small hair graft consisting of three to eight follicles.

The generic name for Rogaine® which is an over-the-counter medication is applied topically. Research has indicated that approximately 50% of men who apply this medication consistently will experience some reduction in hair loss and possible re-growth of miniaturized hairs. 

A non-automated device to perform FUE. Neograft® provides unlicensed technicians hired by the owners of the Neograft® hair restoration system to perform surgical transplant procedures.

Norwood Scale or Norwood Classification

An scale for the classification of male pattern baldness. It is used by transplant surgeons to describe the extent of hair loss in men.

Post Hair Transplant Effluvium
Generally known as “shock loss” or “shock fallout”, it refers to the common occurrence of shedding of some of the patient’s existing (not transplanted) hair in the area of the transplant following a hair transplant procedure. The shedding takes place in hair that is already fragile and nearly the end of its life span, usually due to miniaturization. It often persists for three to four months and is usually reversible.

The brand name for 1mg dose of finasteride.

A brand name of finasteride 5mg tablets.

Recipient Area
The bald or thin area of the scalp in which hair grafts are transplanted.

Recipient Site
A tiny slit cut into the recipient area, into which hair grafts are transplanted.

Retroauricular Area
Area behind the ear.

The brand name for minoxidil topical hair growth solution, available over the counter in 2% solution and 5% extra strength solution and is available in liquid and foam versions.

Sebaceous Glands
Microscopic exocrine glands found in hair follicles throughout the body that secrete natural oils to protect hair and skin.

The oily secretion excreted by the sebaceous glands near hair follicles to keep hair lubricated and shiny.

Shock Loss and Shock Fallout

See Post Hair Transplant Effluvium

The resting phase of the hair growth cycle.

Telogen Effluvium
The second most common type of hair loss (androgenetic alopecia, or male pattern baldness, is the first). The condition in which an unusually large percentage of hairs enter the telogen, or resting phase of growth. These hairs are subsequently shed within a relatively short period of time. The condition usually occurs in response to emotional trauma, post-pregnancy, illness, major surgery, and a variety of medications. It may be temporary or chronic.

Telogen Loss
Loss of hair during resting phase of hair, considered “natural”. People normally “lose” approximately 100 hairs per day. These will regrow as the follicles enter the anagen or growth phase.

Temporal Recession
Hair loss in the temple region.

Traction Alopecia
Hair loss which occurs do to traction placed on hair, commonly seen with tight braids, pony tails and other hairstyles that continuously pull on the hair follicle.

The highest part of posterior scalp. The transition region between the mid-scalp and the crown.