As hair loss becomes noticeable the first option many take is to hide the visible signs; a change of hair style; comb over the offending areas to either block the hair loss or add the illusion of fullness. Hair styling can be an effective way to camouflage hair loss, combing the hair forward can cover a receding hair line and as each hair overlaps and lays over the adjacent hairs the illusion of fullness or density is maintained. As hair loss advances creative hair styling can become harder; an option is to cut the hair shorter as this reduces the contrast between hair and scalp, especially if the hair and scalp pigmentation is similar, for example fair skin and blonde hair the contrast is minimal.
This principle of camouflage is also used when creating a head of hair with a hair transplant; as it is impossible to replace like for like hair lost there is a necessity to create the illusion of fullness. The illusion of density is important over the frontal third, mid-section and crown or vertex; unless the hair characteristics are above average consistent density is unlikely and the crown will be the area with a reduced density.
To gain enough thickness relies on good hair characteristics along with medical and artistic licence to be able to place the follicular units close enough, with the correct angle and orientation. Another requirement is a minimum hair length or hair style; the shorter the hair style the less coverage or shadow each hair provides over the next; more scalp becomes visible allowing light to reflect of the surface.
There can be exceptions but in general unless the hair and skin characteristics are very good there is a limited number of candidates that can achieve a very short hair style
The hair style does not need to be long but enough to create the shadow and add the illusion of density; in the same way in the early stages of hair loss. This is an important aspect to understand before deciding on a hair transplant, regardless of techniques used, FUT or FUE this is a basic fundamental of being able to cover a large surface area with much less hair then there was originally.