A hair transplant glossary, in the words a patient actually needs

Most of a hair transplant glossary exists because quotes are written by clinics and read by people who have never had surgery. You are handed a document with a graft number, a technique acronym, a punch size and a sentence about density, and the polite thing to do is nod. Here are thirty-four of those terms defined in a line or two each, in the order a patient meets them: the hair, the measurements, the map of your own head, the operation, and the words that only appear afterwards. One of them is defined because you will see it elsewhere and it is not offered here.

The hair itself

Follicular unit. The natural grouping in which hair grows out of the scalp, one to four hairs sharing a single opening along with the gland and muscle attached to them. Transplants move units, not individual hairs, which is why the count on your quote is smaller than the number of hairs you will end up with.

Graft. In practice, a synonym for a follicular unit once it has been extracted and is waiting to be placed. Every graft number you are quoted is a number of grafts, never a number of hairs.

Hairs per graft. How many hairs each unit carries, averaging about 2.2 across a typical donor area. So 3,000 grafts is roughly 6,600 hairs. Two donors with the same graft count can differ a lot in coverage because one has more three and four hair units than the other.

Anagen. The growth phase of a hair, lasting years. Most of the hair on a healthy head is in anagen at any moment, and a transplanted follicle re-enters it around month three or four.

Telogen. The resting phase at the end of a cycle, before the hair is shed and a new one starts. A transplanted graft is pushed into telogen by the surgery itself, which is why the hair falls out before it grows.

Miniaturisation. The process that is pattern hair loss: a sensitive follicle produces a finer, shorter, paler hair each cycle until it produces almost nothing. It is what a surgeon looks for with a magnifier to judge whether an area is thinning or already gone.

What gets measured

Androgenetic alopecia. The clinical name for pattern hair loss in men and women, driven by an inherited sensitivity to dihydrotestosterone, a derivative of testosterone usually shortened to DHT. It is the condition a transplant is designed for, because it spares the back and sides.

Donor density. Follicular units per square centimetre at the back and sides, counted under magnification. It is the number that decides how many grafts can be taken safely, and a plan built without it is a sales estimate.

Packing density. How many grafts per square centimetre are placed in the treated area. Higher looks denser and asks more of the blood supply, which is why a careful plan is conservative over the crown.

Scalp laxity. How loose the skin is. It affects how comfortably the donor tolerates extraction and how the area heals, and it is assessed by hand at the consultation rather than from a photograph.

Norwood scale. The standard staging of male pattern loss from 1 to 7, used as shorthand in every quote and forum. The stages and the graft range each one usually needs are on the Norwood scale page.

Ludwig scale. The equivalent staging for female pattern loss, in three grades, describing widening of the parting and diffuse thinning on top with the frontal hairline usually preserved.

The map of your own head

Donor area. The band of hair at the back and sides from which grafts are taken. It does not regenerate, so it functions as a lifetime budget rather than a renewable supply.

Safe zone. The conservative middle of that band, the part least sensitive to DHT and therefore least likely to thin later in life. Harvesting outside it is how a good month-12 result loses density at year eight.

Recipient area. Wherever grafts are being placed: hairline, mid-scalp, crown, or a scar.

Hairline. The front edge, and the single most design-dependent part of the operation. It is drawn on you, sitting up and awake, and it is planned for the face you will have at 50 rather than the one in the mirror today.

Temple point. The small triangular area of hair at each side of the hairline above the eye. Restoring them changes a face more than most patients expect, and overfilling them is one of the classic ways a result becomes obvious.

Crown and vertex. The whorl at the top and back of the head. It is a hungry area, it can absorb an entire session on its own, it grows more slowly than the front, and it is the reason a result can still be improving at month 18.

The operation

Punch. The small cylindrical blade that cuts around a follicular unit to free it, typically 0.7 to 0.9 mm across. A punch that is too large for the hair takes more skin than it needs and leaves more visible dots.

Extraction. The harvesting stage, in which units are removed one at a time and spread across the whole safe zone rather than concentrated in a patch. It usually takes the first two to three hours of the day.

Recipient site, or channel. The tiny incision made in the treated area to receive a graft. Its angle, direction and depth are what make hair grow forwards rather than out of the head, and they are decided by whoever opens them.

Implanter pen. A hand-held instrument with a hollow needle that holds a graft and places it directly, without a channel being made first. It is the tool that defines DHI.

FUE. Follicular unit extraction: units taken one by one with a punch, then placed into channels opened with a blade. It is the standard technique and the one most graft numbers are quoted against.

DHI. Direct hair implantation: the same extraction, but grafts placed with an implanter pen instead of into pre-made channels. It gives fine control at the hairline and in unshaven work, and it is slower per graft. How the two are chosen, often in the same operation, is on FUE or DHI.

Sapphire FUE. FUE in which the channels are opened with a sapphire blade rather than steel, producing a finer V-shaped incision. It is a refinement of FUE and not a separate operation, whatever the marketing suggests.

Unshaven. A procedure done without shaving the recipient area, and with only a hidden strip of the donor clipped. It suits smaller sessions and anyone who cannot be seen to have had anything done.

The words that only appear afterwards

Graft survival, or yield. The share of transplanted grafts that grow. It depends on how gently grafts are handled, how long they spend outside the body, the density they are packed to, and your own healing. Be sceptical of any exact figure: it cannot be counted on a real head.

Out-of-body time. The interval between a graft being extracted and being placed. Shorter is better, which is one practical argument for sizing a session to what one team can implant carefully in a day.

Shock loss. Temporary shedding of your own hair around the treated area, caused by the trauma of surgery. It usually recovers, and it is more likely in hair that was already miniaturising.

Folliculitis. Small inflamed spots around new hairs, most often between weeks three and eight as hairs push through. Common, usually minor, and worth photographing rather than squeezing.

Dot scars. The small round marks left at every extraction point. Spread widely and cut with a small punch, they are hidden at normal hair lengths and visible only under close inspection at a very short clip.

Oedema. The medical word for the forehead swelling that appears on day two or three, drifts downward and settles within a few days. It is fluid and gravity, not a complication.

Two words you will see elsewhere and not here

FUT. Follicular unit transplantation, and the one entry that is not on offer: we do not offer FUT and this clinic does not do strip surgery. A band of skin is cut from the back of the head and closed with sutures, leaving a single line rather than dots. It is defined here because it appears in older discussions and because a mature strip scar can be grafted into as part of a repair.

PRP. Platelet-rich plasma, an injection prepared from a sample of your own blood, sold by many clinics as an add-on around surgery. It is offered here at from €150 a session, priced separately from the transplant package. The evidence in hair loss is mixed rather than settled, which is why it is planned as a support to a transplant or to medication, never as a promise on its own; the PRP page says what it can and cannot do.

Where the numbers in a quote come from

Once the vocabulary is clear, a quote is readable. Area in square centimetres multiplied by a target packing density gives a graft number for each zone, that number is checked against what your donor can safely give, and the technique is chosen per zone rather than per patient. The arithmetic itself, worked through for the hairline, the mid-scalp and the crown, is on how many grafts you need.

What should worry you in a quote is not an unfamiliar word. It is a graft number with no donor measurement behind it, a technique named as though it were a brand, and a promise where a range belongs.

Reviewed by the surgeon who will treat you. Last reviewed 25 September 2026.