Vitamin B12 can be taken orally for many people or as an injection every few months into the muscle of the arm or buttock. It is a quick procedure and there is no downtime afterwards.

Vitamin B12 is given regularly to many people with a deficiency and its safety is well established. It is not recommended for those with known liver disease or very high alcohol intake/alcohol dependency. For healthy individuals the procedure is safe and not harmful, even if your levels are normal.

There may be mild discomfort at the time of injection and it is not uncommon to feel some discomfort in the injected area for 24-48 hours.

For most people the side effects are very mild, and usually restricted to a little discomfort at the injection site, at the the time of and after the injection.

More serious side effects (infection, immune reaction) are very rare.

For most people, the benefits far outweigh any downsides.

For the vast majority you can continue normal life after treatment. Some people experience slightly prolonged discomfort or bruising or headaches, but these settle within a few days. If there are any prolonged or worrying side effects, contact your doctor immediately.