buy benutrex b12 complex injectable 12 Pack offer -Vitamin B Bioniche 30ml Save Over $7 Avoid exposure to light. Rx Item-Vit B-Complex Inj 100
Description
But those in younger age brackets aren't necessarily in the clear

Getting the Lipo-B (MIC) Injection Disclaimer: These products have not been evaluated by the Food and Drug Administration

In a healthy cat, the tissues retain B12 for an average of 13 days, but in a cat with gastrointestinal disease or other health problems, B12 may stay in the body for only about 5 days

doi: 10.2337/diabetes.47.9.1464

A 3-ounce serving of beef provides approximately 2.5 mcg b12