Going up and down

The operator adjusts the area covered and the depth of the roller, not a dose in milligrams. A first session is run shallow and small to see how your skin answers, then the patch is widened once that is known. Thigh and arm skin takes more than facial skin does. A single ampoule covers one zone, and the maker's own guidance caps what is used in one visit, so widening means more visits rather than more product in one go.