We also take postal risks when shipping to most, but not all, of our destinations
doi: 10.1128/mcb.24.20.9079-9091.2004
But unless you have a vitamin B12 deficiency, vitamin B12 injections aren't likely to give you an energy boost." Ironically, the National Institutes of Health says that symptoms of B12 deficiency include loss of appetite and weight loss

Contact your GP if: You have been found to have elevated B12 levels and have not received an explanation or follow-up plan You are taking high-dose B12 supplements without medical supervision You develop new symptoms whilst taking B12 supplements, particularly skin changes, persistent headaches, or gastrointestinal symptoms You have risk factors for liver disease (alcohol excess, viral hepatitis, obesity) and have elevated B12 You experience unexplained weight loss, night sweats, or persistent fatigue alongside elevated B12 Seek urgent medical attention if you experience: Jaundice (yellowing of skin or eyes) Severe abdominal pain or swelling Unexplained bruising or bleeding Confusion or altered consciousness Severe, persistent vomiting These symptoms may indicate serious underlying conditions such as acute liver failure, haematological emergencies, or other critical illness requiring immediate assessment