Anagen
The active growth phase of the hair cycle; can last 3-10 years.
Androgenetic Alopecia (AGA)
The most common hereditary form of hair loss, driven by genetic predisposition and DHT sensitivity.
Bulge Region
The zone within the follicle containing stem cells that initiate each new growth cycle.
Catagen
The roughly two-week transitional/regression phase of the hair cycle.
DHT (Dihydrotestosterone)
A potent androgen converted from testosterone that drives androgenetic alopecia.
DHI (Direct Hair Implantation)
A technique that combines channel-opening and graft placement into one step via the Choi implanter pen.
Donor Area
The area, usually the back/sides of the scalp, from which grafts are extracted โ€” generally DHT-resistant.
Donor Dominance
The principle that transplanted follicles retain their original genetic characteristics in their new location.
DPA (Diffuse Patterned Alopecia)
A form of female hair loss where the donor area remains intact.
DUPA (Diffuse Unpatterned Alopecia)
A form of female hair loss that also affects the donor area, generally unsuitable for transplant.
Follicular Unit
A natural cluster of 1-4 hairs that grow together.
Follicular Transection
Accidental cutting/damage to a follicle during graft extraction.
FUE (Follicular Unit Extraction)
A technique that extracts follicular units individually with small punches.
FUT (Follicular Unit Transplantation)
A technique in which a donor-area strip is removed and dissected under a microscope into follicular units.
Graft
A transplanted follicular unit โ€” not a single hair strand.
Hairline
The front border of the hair-bearing scalp; its design is one of the most critical elements of an aesthetic outcome.
Hypertrichosis
Excessive hair growth in unwanted areas; a side effect seen in some minoxidil users.
Ischemia Time
The time grafts spend outside the body without blood flow; keeping it short improves graft viability.
Keloid
Thick, raised scar tissue that grows beyond normal wound-healing boundaries.
Ludwig Scale
A classification system grading female pattern hair loss from stage I to III.
Miniaturization
The process by which DHT causes follicles to progressively thin and shrink.
Norwood-Hamilton Scale
The standard classification grading male pattern hair loss from stage 1 to 7.
PRP (Platelet-Rich Plasma)
A supportive treatment made from the patient's own blood, rich in growth factors, injected into the scalp.
Shock Loss
The temporary shedding of transplanted (and sometimes surrounding) hair 2-4 weeks after the procedure.
Cicatricial (Scarring) Alopecia
A group of conditions in which follicles are permanently replaced by scar tissue.
Telogen
The 2-3 month resting phase of the hair growth cycle.
Telogen Effluvium
Temporary diffuse shedding caused by an abnormal shift of hairs into the telogen phase after a stressor.
Traction Alopecia
Hair loss caused by mechanical damage to follicles from hairstyles that create sustained tension.