Normal hair density – in individuals not suffering from hair loss – is somewhere between 80-100 follicular units per square centimetre of the scalp. Thinning is not visually obvious until approximately 50% of the native density has shed. This means transplanting between 45-55 follicular units per square centimetre during hair restoration procedures is normally sufficient.
Implanting at densities of 80-100 follicular unit per square centimetre (“normal” hair density) is usually never done. This happens for several reasons: 1. because it is not necessary and wastes finite grafts; 2. because implanting at this density may overwhelm the blood supply and cause shock loss in the surrounding native hairs; 3. because severe damage or diversion of the scalp blood supply can potentially cause necrosis or other serious issues.
Because of this, the maximum density achievable with hair transplant surgery is usually somewhere below natural hair density. While most surgeons will transplant somewhere between 45-65 grafts per square centimetre, some will implant at slightly higher densities. These surgeons will only do so when they are certain they will not overwhelm the scalp blood supply or cause excessive shock loss.
One of the most important issues that must be taken into consideration when transplanting hair is hair density. The hair must be planted with density and thickness in volume equivalent to the natural hair density of the patient.
The patient’s expectancy should also be taken into consideration while adjusting the hair density. The hair of the person to be transplanted must be carefully examined by the doctor before the operation. After all these steps, the hair density to be applied can be decided.