B12 Injection sites + How to use B12 Shots Safely Taking B12 for energy? The evidence says you're probably wasting your money. B12 is only powerful in one situation: when you're deficient. Not tired. Not run down. Not a bit low on Why Your Pee Turns Bright Yellow from Certain Supplements Compounded Methylcobalamin (Vitamin B12) Injection, 5mg mL Urine Color After Vitamin B12 Injection When the marrow wakes up potassium disappears B12 replacement triggers a metabolic surge Cells pull potassium inside serum levels crash The recovery phase is actually the danger