What are the side effects of taking cobalamin (vitamin B12) regularly?

Patient's question:

Diabetes, peripheral neuropathy in the feet, toe pain. Twenty years of diabetes

Doctor's answer:

Hello, methylcobalamin belongs to the B vitamin group, with fewer side effects. Long-term use may cause abdominal discomfort, such as nausea, loss of appetite, etc. Suggestions: Long-term use of methylcobalamin has minimal side effects, mainly mild gastrointestinal reactions. Doctor's inquiry: Are you experiencing any discomfort while taking methylcobalamin now?