The present invention provides a pulp product (e.g., paper) comprising cellulose and nanocellulose, wherein the nanocellulose is derived from the cellulose in a mechanical and/or chemical step that is separate from the main pulping process. The pulping process may be thermomechanical pulping or hydrothermal-mechanical pulping, for example. The pulp product is stronger and smoother with the presence of the nanocellulose. The nanocellulose further can function as a retention aid, for a step of forming the pulp product (e.g., in a paper machine). Other embodiments provide a corrugated medium pulp composition comprising cellulose pulp and nanocellulose, wherein the nanocellulose includes cellulose nanofibrils and/or cellulose nanocrystals and the nanocellulose may be hydrophobic. The nanocellulose improves the strength properties of the corrugated medium. In some embodiments, the cellulose pulp is a GreenBox+® pulp and the nanocellulose is derived from the AVAP® process.