To understand how long a hair transplant will last, you’ll need a good understanding of how the phases of hair growth work and what makes hair fall out in the first place.
The follicles of people with genetic pattern hair loss are vulnerable to attack from a hormone in the blood. DHT or dihydrotestosterone attacks the follicles of the hair in a common pattern on the scalp, hence the name pattern hair loss, i.e. loss on the temples, hairline, and crown of the head. This can begin as early as adolescence but more often in the 20s, 30s, and 40s.
In healthy follicles unaffected by genetic pattern hair loss, follicles function in three distinct cycles. The first is the anagen phase. Hair sprouts from the follicle and will keep growing for 2-7 years. Then in the catagen phase, the growth slows as the blood supply is cut off to the hair. Finally, in the telogen phase, the hair falls out, and the follicle will sit dormant for up to 4 months before these phases begin all over again.
In pattern hair loss, the hair becomes finer and may look lighter in colour. This is known as miniaturisation – during the anagen growth phase, the hair will grow back slower, weaker, and finer because of the DHT attacking the follicle. When the hair reaches the telogen phase and falls out, it may be longer before sending out new growth. And as time passes, the follicle will become so damaged that it is unable to send out any new growth at all.
In an FUE hair transplant procedure, the surgeon extracts follicular units from the back of the scalp one by one. They are dissected into groups of hairs (1, 2, 3, or 4), before being implanted into the thinning areas of the scalp. The hairs from the back of the head are not vulnerable to DHT, and even when they are transplanted to the balding areas, they are not susceptible to its attack. This is the beauty of a hair transplant. The existing follicles from the crown and frontal areas of the scalp may thin and fall out over time due to the genetic hair loss condition, but the transplanted hair will continue to grow in its new location.
Now that we understand how the hair cycle works for healthy follicles and for follicles affected by DHT, we know: