Hair transplantation involves moving genetically resistant hair follicles from a donor area, typically the back and sides of the scalp, to areas experiencing thinning or baldness. These relocated follicles take root and produce hair in their new location, ensuring a permanent and natural-looking result. The process is not immediate, involving a predictable cycle of temporary shedding, dormancy, and eventual, continuous regrowth.
The Initial Shedding Phase
After the procedure, patients enter a period known as “shock loss,” a temporary shedding of the transplanted hair shafts. This phase is a normal biological response to the trauma of the surgery. The process of extraction and re-implantation temporarily shocks the follicles, causing them to prematurely enter the telogen, or resting, phase of the hair growth cycle.
Shedding typically begins between two and four weeks following the transplant and can last for several weeks. The visible hair detaches and falls out, but the implanted hair follicle roots remain secured beneath the scalp surface. The temporary loss of hair indicates that the follicle has successfully settled into its new environment. This resting period allows the follicle to recover its full connection to the blood supply before it begins to produce new, permanent hair.
The Timeline for Visible Regrowth
Following the initial shedding phase, the transplanted follicles enter a period of dormancy before visible growth begins. During the first one to three months post-surgery, the follicles are resting and recovering, and patients see very little new hair growth. While this waiting period can feel frustrating, it is a necessary stage as the follicular units transition back into the anagen, or active growth, phase.
Around months four through eight, the first new hairs begin to emerge from the transplanted follicles, often appearing fine and light in color, known as vellus hair. This phase marks an acceleration in growth, with the hair gradually becoming thicker, darker, and more substantial. By the end of this period, patients see a noticeable increase in density and coverage in the transplanted area.
From months nine to twelve, the transplanted hair continues to mature, achieving most of its final density and texture. The new hair is fully established and can be cut and styled like native hair. Final maturation and assessment of the complete result typically occur between twelve and eighteen months post-procedure, as the hairs fully thicken and blend with the surrounding hair.
Why Transplanted Hair is Permanent
The long-term success of hair transplantation relies on “donor dominance.” This principle states that a hair follicle retains the genetic characteristics of its original location, even when moved. The donor area, typically the back and sides of the head, is chosen because its follicles are genetically resistant to the effects of dihydrotestosterone (DHT).
DHT is the primary hormone responsible for pattern baldness, causing susceptible hair follicles to miniaturize and stop producing hair. Because the transplanted follicles are inherently resistant to DHT, they maintain this resistance after being relocated. This biological resilience ensures that the transplanted hairs continue to grow throughout a person’s lifetime, unaffected by the hormonal processes that caused the initial hair loss.