The donor area โ€” typically the back of the head and the sides above the ears โ€” is the single most important physical limit on how many grafts can be transplanted. Follicles here are genetically resistant to DHT, and that resistance persists after relocation.

Factors Assessed

  • Density (follicles per cmยฒ): A healthy donor area averages 80-100 follicles per square centimeter. Below 40 per cmยฒ is generally considered a sign of poor candidacy.
  • Scalp laxity: Particularly relevant for FUT โ€” determines how much skin can be stretched and closed.
  • Degree of miniaturization: Even slight thinning in the donor zone itself raises the question of whether it's truly "permanent" (DUPA risk).
  • Hair caliber and color: Thicker, darker hair provides more visual "coverage" per graft than fine, light hair.
  • Future loss potential: In younger patients, the possibility that loss will progress and shrink the future donor supply must be factored in.
The core rule: The donor area is not an unlimited resource. Experienced surgeons budget grafts against both current and future need; over-harvesting can cause permanent thinning and visible scarring in the donor zone itself.