b12 injections for Methylcobalamin Injection (Vitamin B12) B12 - Injection - DRIP

Exceeding common ranges without strong scientific justification is generally discouraged in responsible research

However, increasing oral supplement doses (within safe limits) while awaiting medical review is generally considered safe, as B12 has very low toxicity and excess is excreted through the kidneys

Vitamin B12 plays an important role in metabolism, energy production, and maintaining healthy cells

One source says 250mcg

StatPearls (NCBI)

If it adds even one extra week to your timeline, the cost of that week (continued medication, lost time, potential rebound effects) likely exceeds the cost of replacing the expired vial