Can you buy ampules of vitamin B12 over the counter? B Complex Extract With Vitamin B12 Injection(Optineuron Injection ) at 140 vial Methylcobalamin Injection in Surat ID: 2855102697648 Kroger Vitamin B12 2500mcg Fast Dissolve Tablets Berry Flavored, 100 ct Kroger Hi I bought the B12 injectable liquid but there's no use by date on it or how long you have to use it once it's opened. Anyone know the answer? TIA x What is the recommended timeframe for a second Vitamin B12 injection after an initial dose for borderline low levels? Injectable B12 Without a Prescription: 4 Big Dangers