An aerosol generating substrate comprising an aerosol generating material, wherein the aerosol generating material comprises an amorphous solid, the amorphous solid comprising 1-60 wt % of a gelling agent; 5-80 wt % of an aerosol generating agent; and 1-70 wt % of an active ingredient; wherein these weights are calculated on a dry weight basis; wherein bi-modal or multi-modal release of one or more active ingredients of the amorphous solid is observed in use.