If we look at a hair shaft, the hair shaft is in the shape of a cylinder.

The bigger the size (volume), the better.

(Volume is calculated as 2 x Pi x Radius (squared) x the length or V = (ϖr²)h)

See Hair Shaft Calibre image below:

“Dr André Nel's systematic and pragmatic approach instilled confidence and belief in the process. Restoring my hair has given me a quiet sense of confidence and great satisfaction. It has been one of the best decisions of my life!" - Mark

The Importance of Illusion When Dealing With Hair Loss

This is one of the most important principles in hair transplant surgery, whereby we create the illusion of hair density.

What we want is to maximize the hair shaft calibre and keep the hair shaft relatively long, adding to more cross-over-and-shingling of hair shafts, resulting in more density

The bigger the volume of hair, the bigger the chances are that it is going to shut out the reflection of light from the scalp and look like a full head of hair.

The reflection of light from the scalp through thin hair (therefore light reflecting in-between low calibre hair shafts) creates the perception of hair loss. It’s as simple as that from a pure physics point of view.

Here’s an Example of Why Calibre is So Vital

If we assume the hair shaft radius is 10 microns, then because the Radius is squared in the hair shaft cylinder volume calculation, the radius is the critical factor.

See different hair radius sizes squared and the effect on calibre below:
• 8 microns x 8 microns = 64 micron calibre
• 9 microns x 9 microns = 81 micron calibre
• 10 microns x 10 microns = 100 micron calibre
• 11 microns x 11 microns = 121 micron calibre
• 12 microns x 12 microns = 144 micron calibre


From this example, it is clear that a small change in hair shaft radius creates a large change in hair shaft calibre.

We have calculated in hair restoration that for every 10 microns increase or decrease in the hair shaft calibre, there is a 35% volume effect, either way. That is quite dramatic and emphasizes the importance of maximizing hair shaft calibre.

The average persons’ hair shaft calibre is around 68-70 microns. If for example, the calibre goes down to 58 microns, then literally 36% of the persons’ hair volume gets lost in the process, therefore not visible, although all the hair shafts are still there. The opposite is also true.

This happens because the total hair shaft volume has gone down.

So this person has lost hair volume.