Vitamin B12 may be required for diabetic patients and needs to be administered for the condition. When a diabetic patient is treated with metformin and other biguanides and develops a vitamin B12 deficiency or when a diabetic patient develops neuropathy, this is when the diabetic patient needs to take vitamin B12 to supplement vitamin B12 and nourish the nerves. Since metformin affects the absorption of vitamin B12 in the gastrointestinal tract, patients taking metformin for a long period of time need to be checked regularly for vitamin B12. if vitamin B12 deficiency occurs, vitamin B12 needs to be given. Patients with diabetic neuropathy can be given vitamin B12, lipoic acid, epinastat and other drugs to nourish the nerves. Therefore when diabetic neuropathy is present patients need to take vitamin B12. Patients without vitamin B12 deficiency or diabetic neuropathy do not need to take vitamin B12. Vitamin B12 should be used under the supervision of a doctor and should not be taken by oneself.