Vitamin B-12 deficiency can cause or worsen the pain of diabetic neuropathy or nerve pain, so doctors often prescribe vitamin B-12 as part of a neuropathy treatment plan, notes WebMD. Vitamin B-12 is available in both injectable and supplement forms.
Studies of vitamin B complex that includes both vitamin B-12 and pure vitamin B-12 in the form of methylcobalamin showed beneficial effects on neuropathy pain for participants, notes a study published on PubMed.gov. Other studies showed that pure vitamin B-12 improved autonomic symptoms of neuropathy. However, the study says that these effects require confirmation through higher-quality randomized double-blind trials, noting that two studies into B-12 were of fairly good quality, while five were of poor quality.