Unopened vials: Store at controlled room temperature (20-25 degrees C / 68-77 degrees F) Protected from light in original packaging Good until manufacturer-printed expiration date (typically 18-24 months from production) Do not freeze freezing can compromise the glass vial seal and alter preservative distribution After first puncture: Refrigerate at 2-8 degrees C (36-46 degrees F) 28-day use window from first needle puncture per Pfizer/Hospira prescribing information Swab the rubber stopper with 70% isopropyl alcohol before every puncture Label the vial with the first-puncture date Discard after 28 days regardless of remaining volume or visual appearance What shortens the 28-day window: Room-temperature storage after puncture (can reduce effective window to 7-10 days) Excessive puncture count (30+ punctures accelerate preservative depletion) Poor aseptic technique (skipping alcohol swabs introduces surface contamination) Temperature cycling (moving between fridge and room temp repeatedly) For a deep dive on shelf life, degradation signs, and the science behind the 28-day rule, see How Long Does Bac Water Last After Opening
You can always adjust with your next vial if you prefer different concentration
Fate of cobalamins in humans following oral and intramuscular administration of cyanocobalamin, hydroxocobalamin, adenosyl-cobalamin and methylcobalamin
Packaging is beautiful and professional too
When you take a B12 pill, it has to travel through your digestive system
The injection is typically administered into the upper arm or buttock, and the procedure takes only a few minutes
