B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics CureFIP GS 441524 + B12 Injectable 20mg ml FIP Treatment for Small Cats & Kittens With Integrated Vitamin B12 Support Liposomal Vitamin B12 lipolife 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 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 How Long Do the Benefits of Vitamin B12 Injections Last?