Vitamin B12 Supplementation Improves neuropathic pain in Diabetic Peripheral Neuropathy, suggests research
In a new study, researchers found that among patients with diabetic peripheral neuropathy (DPN) and low serum vitamin B12 levels, 16 weeks of daily vitamin B12 supplementation significantly improved neuropathic symptoms. Both 1000 mcg and 2000 mcg doses provide similar clinical benefits, with the higher dose leading only to greater serum B12 levels and no additional improvement in neuropathic or metabolic outcomes. The study was published in The Journal of Nutrition by Asieh M. and colleagues
Vitamin B12 is associated with type 2 diabetes mellitus (T2DM), especially in those with diabetic peripheral neuropathy (DPN), which causes worsening of nerve function. This was a 16-week, randomized, controlled, parallel-group trial. Adults with type 2 diabetes mellitus, established diabetic peripheral neuropathy, and low serum vitamin B12 levels (<200 pg/mL) were enrolled. Participants were randomized in a 1:1 ratio to receive either 1000 mcg or 2000 mcg of oral vitamin B12 (methylcobalamin) daily. A total of 35 patients were randomized, and 32 participants completed the study. The primary outcomes were changes in neuropathic parameters assessed using:
Numeric Rating Scale (NRS) for pain
Michigan Neuropathy Screening Instrument Examination (MNSIE)
Neuropathy Disability Score (NDS)
Secondary outcomes included serum vitamin B12 levels and metabolic parameters such as hemoglobin A1c (HbA1c) and estimated glomerular filtration rate (eGFR).
Key findings
Serum vitamin B12 levels increased significantly in both groups, with a greater rise in the 2000 mcg group (p = 0.049)
Neuropathic pain improved significantly in both groups
NRS decreased from 7.00 ± 2.03 to 5.60 ± 2.19 in the 1000 mcg group (p = 0.016)
NRS decreased from 6.18 ± 2.40 to 4.42 ± 2.50 in the 2000 mcg group (p = 0.007)
MNSIE scores improved in both groups
1000 mcg: 5.70 ± 1.66 to 5.22 ± 1.99 (p = 0.033)
2000 mcg: 5.40 ± 1.68 to 4.47 ± 2.25 (p = 0.022)
No significant between-group difference was observed for NRS or MNSIE improvements
NDS scores remained unchanged in both groups (p > 0.05)
The symptoms of neuropathy in diabetic patients with low serum vitamin B12 levels are improved with daily treatment with 1000 mcg or 2000 mcg of vitamin B12 for 16 weeks. Similar to increasing serum vitamin B12 levels, there are no additional neuropathic or metabolic benefits of using high-dose vitamin B12 therapy.
Reference:
Mansour, A., Amrollahi Bioky, A., Gerami, H., Khorasanian, A. S., Esmaeili, A. H., Fateh, H. R., Aghaei Meybodi, H. R., Mohajeri-Tehrani, M. R., Safyari, R., Adibi, H., & Sajjadi-Jazi, S. M. (2026). Efficacy of oral vitamin B12 at 1000 mcg versus 2000 mcg on neuropathic outcomes in patients with diabetic peripheral neuropathy and low serum vitamin B12: A randomized clinical trial. The Journal of Nutrition, 101368. https://doi.org/10.1016/j.tjnut.2026.101368
