How Long Does a B12 Shot Last In Your Body? Drastic color change in my patients urine after receiving a CyanoKit. : r mildlyinteresting 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 How Quickly Does a B12 Injection Work? Timeline and Expectations Bolt Pharmacy Vitamin B12: Urine discolouration could mean you're talking too many supplements Express.co.uk Feeling Tired All the Time? It Might Be a Vitamin B12 Deficiency Fusion HealthCare