For those deficient in B12, one shot may provide symptom relief for 5-7 days on average before you start feeling fatigued or off again
This enzymatic reaction consumes both nicotinamide and SAM, leading to depletion of NAD+ storesa critical coenzyme required for cellular energy production, DNA repair, and metabolic regulation
This is a finding that should be investigated, not ignored
Common examples include fatigue or low energy with normal blood results, brain fog or reduced concentration without confirmed vitamin B12 deficiency, stress-related exhaustion or burnout, increased metabolic demand such as during illness recovery, high workload, or intense training, restrictive or inconsistent dietary intake, or suspected poor oral absorption despite normal serum levels
10.1370/afm.1402 [DOI] [PMC free article] [PubMed] [Google Scholar] 43.Gendelman O, Itzhaki D, Makarov S, Bennun M, Amital H