Donor Area

The donor area is the horseshoe of scalp at the back and sides of the head where hair is genetically resistant to DHT. It is the only hair used in a transplant.

Where you'll meet it

In every consultation, usually as a number. How many grafts your donor area can safely give over a lifetime is the most important fact about your own head, and it decides more about what is possible than the technique, the clinic or the price.

Why is only this hair used?

Because it is the hair that stays. Follicles in the donor area are largely insensitive to DHT, and they keep that insensitivity when they are moved. Transplanted hair behaves like where it came from, not where it ends up. Hair taken from the thinning area would simply carry on thinning in its new position.

The safe donor zone is narrower than the whole back of the head. Its upper edge, near the crown, can itself thin later in life, and hair taken from too low on the nape can be finer and less reliable. Surgeons harvest from the band in between, which is why the size of that band on your particular head matters as much as how dense it is.

How many grafts does a donor area have?

Somewhere around 6,000 to 8,000 grafts is a commonly quoted lifetime ceiling, and many people have less. It varies with density, the size of the safe zone, hair calibre and how far your own loss will eventually run. It does not regenerate: hair taken from the donor area does not grow back there.

Surgeons work to a maximum harvest density rather than a maximum number, thinning the area evenly so it still reads as full. That is why the same head can give a large number in a first session and noticeably less in a third.

What does over-harvesting look like?

A visibly thin, patchy or moth-eaten back of the head, most obvious when the hair is cut short. It is harder to disguise than the loss it was treating and it cannot be reversed. It tends to come from taking too many grafts in one session, from extracting too densely in one patch, or from harvesting outside the safe zone. Scalp micropigmentation and, for some people, body hair can camouflage or extend a damaged donor, but nothing restores it.

How is the donor area measured?

With a densitometer or a magnified camera, counting follicular units per square centimetre and hairs per unit at several points across the zone, then estimating how large the safe zone is. A lifetime estimate given without measurement is a guess, and usually an optimistic one.

Ask for the number and write it down, along with how many grafts each session uses. Every surgeon you ever see afterwards will want both, and you will not remember them.

Why does it matter so much?

Because it turns hair restoration from a purchase into a budget. Every graft spent on the crown at thirty is one not available for the hairline at fifty. Donor supply goes through how to spend it well, and why the front comes first.

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