--methylcobalamin has been shown to be particularly neuroprotective; it is involved in many of the enzymatic reactions that allow fatty acids to be formed into myelin sheathing. It also may be protective of the biology of the nerve fibers--the axons--themselves.

B12 is not the only vitamin in the B family that is needed for proper nerve functioning--deficiencies of B1 (thiamine), B2 (riboflavin), B3 (niacin), and B6 (pyridoxine) have also been associated with peripheral nerve dysfunction, so a good B-complex is indicated, although one wants to limit megadosing of B6, which can also cause neuropathic symptoms in some people.

Many of us with neuropathies, but without known B vitamin deficiencies, nevertheless think it prudent to take considerably greater doses of B-vitamins than delineated in the USDA minimums; it just makes sense that those with nerve damage, from whatever source, need considerably greater amounts of them for maintenance/repair.