An active molecule delivery system whereby active molecules can be released on demand and/or a variety of different active molecules can be delivered from the same system and/or different concentrations of active molecules can be delivered from the same system. The active delivery system includes a plurality of microcells, wherein the microcells are filled with a medium including active molecules. The microcells include an opening, and the opening is spanned by a porous diffusion layer. The microcell arrays may be loaded with different active ingredients, thereby providing a mechanism to deliver different, or complimentary, active ingredients on demand.