Additive manufacturing has the potential to create almost no waste; only material that is required for the component (and any support structures) is used in the build process. Despite this, large quantities of metal powders are sent to landfill every year due to powder degradation, caused by continual reuse of the powder. An understanding of powder formation and degradation has been presented in an extensive literature review, enabling the viability of potential waste-reducing solutions to be assessed. Plasma spheroidisation is identified as a promising method of upcycling end-of-life powders, likely to reduce powder waste by 80%. An experimental procedure was established to allow future investigation into this technology. Sustainable powder manufacturing methods were identified as under-researched. A method of breaking down support structures in powders through shear shredding and ball milling was shown to consume less energy than current virgin powder production methods. The powder produced was of a lower quality than virgin powders used in selective laser melting; further refining of the milling procedure is likely to improve this powder quality. The work done showed improvements in both resource and energy efficiency, although developing these processes beyond proof of concept remains a challenge.