A dextran sulfate, or a salt thereof, has a number average molecular weight (Mn) as measured by NMR spectroscopy within an interval of 1850 and 3500 Da. The dextran sulfate, or the salt thereof, also has an average sulfate number per glucose unit within an interval of 2.5 and 3.0. Furthermore, an average sulfation of C2 position in the glucose units of the dextran sulfate, or the salt thereof, is at least 90 pcnt . The dextran sulfate has improved biological effects and/or reduced toxicity as compared to similar dextran sulfate molecules available on the market.