Follicular Unit

There are two 1-Hair-FU per graft,known as DFU ( Double Follicular Units )

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 Over the last 20 years Minigrafts transplant has been replaced by Follicular Unit Transplant.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

Hair-Graft Ratio




Normal Follicular Unit Density

The FU density varies amongst different ethnic groups, being highest in Caucasians and lowest in Africans


Hair Density

200 /

160 /

170 ⁄
FU Density 100 / 60 / 90 /

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


Hair Density

200 /

160 /

170 ⁄
FU Density 100 / 60 / 90 /
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/

Normal Men




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






Women 33 49 16 2 1.87


This Graft contains a 2-hair Follicular Unit, measured 6mm in length

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.

Message from the Doctor

Welcome to “Doctor's Talk,” where I’ll talk about everything related to hair loss and hair transplants. This series is here to help you understand more about how hair treatments work and what you can expect from them. The information provided is based on my 18 years of experience in dealing with hair loss.

Disclaimer - Please note that this series is purely educational. Reading these posts does not guarantee my services, nor are they intended for business promotion. Information provided is not guaranteed to be up-to-date and should not be considered a substitute for professional medical advice.

Any opinions discussed may not be universally accepted or applicable to all individuals. Always consult a healthcare professional before making any decisions related to your health.

Dr Bertram Ng

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