If it is methylcobalamin, many times more than that the basic 1000 - 5000 mcg has been used without problems. In the realm of huge doses, 15,000 mcg would be conservative.

Huge quantities of methylcobalamin have been given, and in some cases conditions as serious as ALS and MS have improved dramatically. Huge quantities of methylcobalamin have even been given when the patient could not eliminate extra with urine, and still no problem.

Many who have studied the literature would have no qualms about taking 60,000 mcg methylcobalamin at one time.

For those who do not want to go to that extreme or expense, it is very unlikely that it will benefit someone with neuropathy more than just keeping up the 1000 or 5000 mcg, making sure other nutrients are covered (great information at the vitamin forum), and eating a good diet.

rose