The rate of excretion is fast, there is no internal cupboard where we can pop a bit by for a rainy day
A 2017 meta-analysis of data from 15 trials, including more than 71,000 participants at risk of or with existing CVD, showed that B-vitamin supplementation had no significant effect on risk of myocardial infarction (heart attack) or all-cause mortality but reduced risk of stroke by 10% (RR, 0.90
We wouldn't expect the injection to do this because it bypasses the overgrowth
High-dose oral supplements (often 10002000 micrograms daily) or intramuscular injections (typically 1mg hydroxocobalamin) used to treat pernicious anaemia or deficiency states can temporarily elevate serum levels
Lowered Zinc Levels: Long-term use of supplements has been linked to reduced zinc levels in the body, suggesting a need for monitoring or concurrent supplementation
Medication given this way is absorbed more slowly than if injected into a vein or taken by mouth (orally), sometimes over a period of 24 hours