The present disclosure provides aerosol generating substrates and aerosol source members comprising aerosol generating substrates, as well as methods of manufacturing thereof. In an example implementation, an aerosol generating substrate may comprise a fibrous filler material, an aerosol forming material, and a plurality of heat conducting constituents, wherein the substrate is formed as a sheet, and wherein the heat conducting constituents are part of the sheet. The heat conducting constituents may be incorporated within the sheet, or may be formed on a surface of the sheet. In another example implementation, an aerosol source member may comprise a substrate portion formed of a collection of intermingled pieces cut from an aerosol substrate sheet. In addition, or alternatively, a substrate portion may be formed of a series of overlapping layers of an aerosol substrate sheet.