Embodiments of a process for improving a re-refined lube oil stream are provided. The process comprises the steps of introducing a gas stream comprising hydrogen (H2) and the re-refined lube oil stream comprising hydroprocessed used lube oil to a hydrogenation reactor that contain Group VIII catalyst. A gas to oil feed ratio rate of from about 30 to about 100 Nm3 H2/m3 is used to introduce the streams to the reactor. The hydroprocessed used lube oil is hydrogenated with the H2 in the reactor such that an effluent is formed containing hydrogenated re-refined lube oil having about 2 wt. % or less of aromatics and about 55 wt. % or less of naphthenes. The reactor is operating at a temperature of from about 250 to about 300° C.