Abstract: There is provided a cellulose based fiber made of a i) cellulose dissolving pulp, and ii) a recycled cellulose textile, which is treated to swell the cellulose with a reducing additive and a) bleached with oxygen at alkaline conditions with a pH in the range 9-13.5 and/or b) bleached with ozone at acid conditions below pH 6, wherein the cellulose based fiber is manufactured with one selected from a Viscose process and a Lyocell process. Advantages include that the tensile strength of the fiber is improved and it is possible to manufacture improved cellulose fibers which comprise a fraction of recycled material.