You can see in the thread and elsewhere on the site the various doses and vitamins people have tried. Maybe Mrs. D has an update. I did just find this on PubMed. A few weeks ago, I posted that I believe methycobalamine (a form of B12, is helping me. Here is an abstract I just found. That is some heavy duty dosage they are using there, but apparently there are no adverse effects.

"Intern Med. 2014;53(17):1927-31. Epub 2014 Sep 1.
Safety and Efficacy of Intravenous Ultra-high Dose Methylcobalamin Treatment for Peripheral Neuropathy: A Phase I/II Open Label Clinical Trial.
Shibuya K1, Misawa S, Nasu S, Sekiguchi Y, Beppu M, Iwai Y, Mitsuma S, Isose S, Arimura K, Kaji R, Kuwabara S.
Author information
Abstract
Objective No clinically effective treatment for promoting peripheral axonal regeneration has yet been established. Several experimental studies in vitro and in vivo have shown that a high dose of methylcobalamin (MeCbl), an analogue of vitamin B12, promotes axonal growth in peripheral nerve injury. We herein assessed the safety and efficacy of an ultra-high dose MeCbl treatment for patients with peripheral neuropathy and chronic axonal degeneration. Methods Fourteen patients with immune-mediated or hereditary neuropathy in the chronic progressive or stable phase were enrolled. MeCbl, 25 mg/day for 10 days followed by monthly 25 mg for 5 months, was intravenously administered. The patients were evaluated before and 1 year following treatment. The primary endpoints were safety and improvement in the Medical Research Council (MRC) sum score in at least two muscles of the 20 muscles. This trial is registered with the University Hospital Medical Information Network (UMIN) Center in Japan under the ID: UMIN000009359. Results There were no adverse effects in twelve of the patients, whereas treatment was discontinued in two patients who had seborrheic dermatitis at 3 months and respiratory tract infection at 2 months, respectively. Therefore, twelve patients were evaluated for the primary outcomes; the MRC sum score was improved in seven of the patients and unchanged or worsened in the remaining five patients. Conclusion Intravenous ultra-high dose MeCbl treatment is a safe and potentially efficacious therapy for patients with peripheral neuropathy and chronic axonal degeneration.
PMID: 25175124 [PubMed - in process]

*here is the link http://www.ncbi.nlm.nih.gov/pubmed/25175124 *