It is done in five to ten sessions at two to six week intervals. Brightening shows from the third, because it breaks pigment down bit by bit at low power and no single session brings a large change. In exchange, the low stimulus reduces the risk of melasma darkening.

It passes over the whole face several times at low power, so the stimulus is mild. Firing hard in one pass breaks pigment faster but can irritate melasma and darken it instead. This lowers the power to avoid that risk, at the cost of needing more sessions.

Melasma can return under the influence of UV and hormones, because breaking the pigment down does not remove the cause that makes it. It is therefore maintained with sun protection and topical medication, and care is especially needed during hormonal changes such as pregnancy or oral contraceptive use.