The biology of hair growth after transplant: how follicles re-establish blood supply, enter the growth cycle and produce permanent hair. Hairmedico Istanbul.
The hair growth cycle drives the timeline
Human hair grows in three phases: anagen (active growth, 2–7 years), catagen (transition, 2–3 weeks), telogen (resting/shedding, 3 months). After transplantation, surgical trauma forces all follicles into telogen — producing shock loss at weeks 2–5. The dormancy (months 1–3) is the telogen phase. New growth begins when follicles re-enter anagen at months 3–5.
How follicles restore blood supply
The transplanted follicle is initially avascular. It survives the first 24–48 hours through plasmatic imbibition — passive nutrient absorption from tissue fluid. From Day 2, angiogenesis begins — new capillaries grow into the graft. By Day 10–14, a functional new blood supply is established. The adequacy of revascularisation determines graft survival.
Why transplanted hair is permanent
Permanence rests on donor dominance: donor zone follicles carry genetic DHT resistance that they maintain after transplantation. This genetic characteristic — encoded in the follicle's dermal papilla — is expressed regardless of new location. A DHT-resistant follicle in the frontal scalp continues to be DHT-resistant and produces hair across the patient's lifetime. First described by Dr. Orentreich in 1959 and confirmed across 65+ years of clinical data.
