Only. If you are deficient and that that is the cause.
Sometimes. If you have pernicious anemia, b-12 injections can reverse much of the nerve issues. If you have diabetic neuropathy, a medical food, metanx which contains b-12, folate, (folic acid) and b-6 in biologically active form can help regrow small nerve fibres. But otherwise, not sure supplements are going to make much difference.
No. B12 therapy when there is no B12 deficiency is unlikely to speed up recovery. Read more...