Methylcobalamin did not show an overall benefit in the strongest clinical trial reviewed
Original source
Methylcobalamin (opens in a new tab)An ALSUntangled review found that methylcobalamin did not improve overall ALS Functional Rating Scale–Revised progression or survival compared with placebo in the best of three clinical trials. A possible benefit was seen in a subgroup with very early disease and a specific pre-treatment progression rate, but this finding needs replication.
Why this matters
The evidence does not establish methylcobalamin as beneficial for people with ALS overall. The possible subgroup effect could inform a future phase 3 trial, but it does not currently change treatment. The reviewed studies used high-dose injected methylcobalamin; oral over-the-counter forms have not been studied.
Limitations and context
This is an independent expert review published in 2015, not a new primary research report. The subgroup finding was not confirmed and requires replication. The source does not provide the trial sizes or full methodological details. It also cautions that over-the-counter supplements may vary in quality and may contain vitamin B6, which can harm the nervous system in large quantities.