A composition dispenser with dynamically adjustable protrusions/bristles for delivery of a cosmetic composition to a substrate, particularly hair coloring agents. The composition dispenser comprises a protrusion unit including one or more protrusion elements and at least one dispensing orifices appointed for fluidic communication with a formulation reservoir. The protrusion unit is operably coupled to a length-adjustment element configured to adjust an exposed protrusion length of the protrusion elements along a direction perpendicular to a rotation plane of the length-adjust element.