As far as I know, vitamin B12 injections are given to at least help improve symptoms of nerve damage (tingling, numbness) which is a complication of diabetes. It may also improve fatigue. It has no role on controlling blood sugar levels. Moderate exercise, however has a very important role in controlling blood sugar levels. Early diabetes can actually be controlled by exercise and diet alone. If it has been chronic already, medicines are usually needed to control blood sugar levels. Blood sugar levels needs to be controlled because diabetes can damage the kidney, heart, eyes, nerves, among others. You may want to check the Vitamin B12 levels in your blood first before having B12 injections. If it is deficient (low), 1 mL injections every month may be given. If it is normal, 0.5 mL injections every month is sufficient. I do hope I have helped you in some way. Take care always.
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