Follicular Unit

What is Follicular Unit
"Follicular Unit" was first described by Dr. John Headington, a pathologist, in his 1984 paper “Transverse microscopic anatomy of the human scalp”. Scalp hair follicles were observed to bind together underneath the skin, emerging from the scalp in clusters or groups of 1-5 hairs in each pore. Each grouping of hair is called a "Follicular Unit" or "FU".
Follicular Unit Transplant (FUT) is a hair restoration technique where a patient's hair is transplanted using these naturally occurring follicular units of 1 to 4 hairs. In a properly-performed FUT, the results will mimic the way hair grows in nature and will be undetectable as a hair transplant. These small units allow the surgeon to safely transplant thousands of grafts in a single session, which maximizes the cosmetic impact of the procedure. Procedures using the larger minigrafts often produced a pluggy, unnatural look. Over the last 20 years Minigrafts transplant has been replaced by Follicular Unit Transplant.
Hair-Graft Ratio
Each individual will have a unique combination of 1-Hair FU, 2-Hair FU, 3-Hair FU. For a certain area the average number of hair per FU is known as Hair-Graft Ratio. The Hair-Graft Ratio is different amongst various Ethnic Groups. With a higher FU density and hair-graft ratio, Caucasians are more suitable for FUE.
Hair-Graft Ratio = Total No. of Hair ÷ Total No. of FU
Caucasian |
Africans |
Asians |
|
---|---|---|---|
Hair-Graft Ratio |
2.3 |
2.3 |
1.8 |
Normal Follicular Unit Density
The FU density varies amongst different ethnic groups, being highest in Caucasians and lowest in Africans
Caucasian |
Africans |
Asians |
|
---|---|---|---|
Hair Density |
200 / sq.cm |
160 / sq.cm |
170 ⁄ sq.cm |
FU Density | 100 / sq.cm | 60 / sq.cm | 90 / sq.cm |
Ethnical Differences in Hair Characters
In order to provide hair transplant service to patients from different ethnic groups, we have studies in depth the differences in their hair density and characters
Caucasian |
Africans |
Asians |
|
---|---|---|---|
Hair Density |
200 / sq.cm |
160 / sq.cm |
170 ⁄ sq.cm |
FU Density | 100 / sq.cm | 60 / sq.cm | 90 / sq.cm |
Shaft Cross-Section | Oval | Elliptical | Round |
Shaft Diameter | 0.07 mm | 0.06 mm | 0.08 mm |
Hair Shape | Curly | Wavy | Straight |
Length of Follicle | 4.5 mm | - | 5.5 mm |
Follicular Unit Density in Chinese Scalps
Usually the density is highest in the mid-occipit which is at the back of the head.
Density (FU/sq.cm) |
Front |
Sides |
Back |
Average |
---|---|---|---|---|
Normal Men |
84 |
55 |
80 |
73 |
Bald Men | 68 | |||
Women | 87 | 54 | 72 | 72 |
Bald Women | 69 |
Follicular Unit Ratio in Normal Chinese Scalps
The 2 Hair FU is the most common in Chinese, followed by the 1 Hair FU. 4- and 5- Hair FUs are very hard to find.
Ratio (%) |
1 Hair FU |
2 Hair FU |
3 Hair FU |
4 Hair FU |
Hair Graft Ratio |
---|---|---|---|---|---|
Men |
29 |
52 |
17 |
2 |
1.92 |
Women | 33 | 49 | 16 | 2 | 1.87 |
Graft

What is a Graft
Confusion arises when using different units to estimate the cost of a hair transplant procedure. Over 95% of hair transplant centers worldwide use "graft" as unit to estimate procedural cost. Advance in technology renders the smallest follicular unit to be used as graft. i.e. one graft = one FU. Nowadays 2,000 graft can easily be transplanted in one session.
Some centers however, limited by technique or manpower, may not be able to achieve such numbers. In order to sound good they instead use "hair" as unit. Telling a patient he had 2,000 hairs transplanted seems impressive but that's in fact just about 1,000 grafts. To avoid confusion ask clearly the unit for calculating cost.