Insulin resistance is one of the most important mechanisms of diabetes mellitus. Anti-oxidants had been proved to improve insulin resistance. However, the direct relation between anti-oxidants and glucose homeostasis is still elusive. Recently, we found that Lycogen TM (extracts of Rhodobacter sphaeroides WL-APD911) has lycopene-like activity. Furthermore, Lycogen TM showed more potent anti-oxidative effect and less cytotoxicity than lycopene. To evaluate the effect of Lycogen TM on blood glucose levels, STZ-induced diabetic mice were randomly divided into four groups: (1) diabetes control group; (2) diabetes+Lycogen TM 50 mg/kg; (3) diabetes+Lycogen TM 100 mg/kg; and (4) diabetes+Lycogen TM 200 mg/kg. After 7 days of treatment, the blood glucose level in the Lycogen TM 200 mg/kg group was significantly lower than the disease control group (p<0.01). In the oral glucose tolerance test, the blood glucose level was significantly lower in the Lycogen TM 200 mg/kg group than the disease control group (p<0.05). Our results confirmed that Lycogen TM , a potent anti-oxidant, can significantly lower blood glucose levels in a diabetic mice model.