Hair transplantation is a surgical method aimed at restoring hair to areas of thinning or baldness. This process involves relocating hair follicles from one part of the body, known as the “donor area,” to the recipient areas on the scalp. The success and natural appearance of a hair transplant depend significantly on the quality and characteristics of these donor hair follicles.
The Primary Donor Area
The most common and preferred source for donor hair is typically found at the back and sides of an individual’s own scalp. This region, often referred to as the occipital and parietal areas, contains hair follicles that are genetically distinct from those on the top of the head. These follicles are naturally resistant to the effects of dihydrotestosterone (DHT), the hormone primarily implicated in male and female pattern baldness. This inherent resistance ensures that once transplanted, these hair follicles will continue to grow and maintain their density in their new location, providing a permanent solution to hair loss.
The density of hair in these donor regions is generally high, often ranging from 80 to 100 follicular units per square centimeter, offering a reliable supply of grafts for transplantation. Before a procedure, specialists assess the quality and density of this area to ensure its suitability and to estimate the number of grafts that can be safely harvested.
Methods of Hair Extraction
Two primary techniques are employed to harvest hair follicles from the donor area: Follicular Unit Transplantation (FUT) and Follicular Unit Excision (FUE).
Follicular Unit Transplantation, often called the strip method, begins with the surgical removal of a thin strip of scalp tissue, typically measuring about 15-20 cm in length and 1-2 cm in width, from the back of the head. After the strip is excised, the wound is closed with sutures, which leaves a linear scar that can usually be concealed by surrounding hair. The removed strip is then meticulously dissected under magnification into individual follicular units, each containing one to four hairs, which are then prepared for implantation. This method can yield a large number of grafts in a single session and is often more efficient for extensive hair loss.
Follicular Unit Excision involves individually extracting follicular units directly from the donor area. This is achieved using a specialized micro-punch tool, typically with a diameter between 0.6 to 1.0 millimeters, to make tiny circular incisions around each follicular unit. These individual units are then carefully pulled out with forceps, leaving behind small, dot-like scars that are often virtually unnoticeable, especially when hair is kept short. The FUE method is less invasive, generally leads to a faster recovery period, and does not result in a linear scar.
Beyond the Scalp: Other Donor Sources
When the primary scalp donor area offers an insufficient supply of hair, alternative body sites can serve as secondary sources. These include hair from the beard, chest, and back. Using hair from these areas is generally considered when scalp donor hair is limited due to extensive hair loss or previous transplant procedures.
Beard hair, particularly from the area below the chin and upper neck, is a common alternative, often providing thicker individual hairs that can contribute to increased hair volume on the scalp. While beard hair can provide a significant number of grafts, sometimes between 3,000 to 5,000, its texture and growth cycle can differ from scalp hair. Body hair from areas like the chest or back tends to be thinner, shorter, and has a different growth cycle than scalp hair, which can sometimes result in an uneven or less natural appearance when transplanted. These alternative hairs are typically used to add density behind the hairline rather than for the hairline itself, where a natural blend is paramount.
Key Considerations for Donor Hair Supply
The supply of donor hair is finite. This necessitates careful planning and assessment. Surgeons evaluate factors such as donor hair density, the quality of individual follicles, and scalp elasticity to determine the maximum number of grafts that can be extracted without compromising the donor area’s appearance.
A thorough assessment often includes trichoscopy, which uses high-power magnification to analyze hair density, follicular unit composition, and the degree of miniaturization. This evaluation helps prevent over-harvesting, which could lead to visible thinning. Long-term planning is essential, especially for future transplants, to preserve sufficient donor hair. After extraction, the donor area undergoes a healing process, with care taken to minimize scarring, which varies by method.