US$ 20.04
animals injected with b12 Giving Your Cat a Vitamin Boost Vitamin B-12 Injection, 3,000 mcg/mL
Description
Generally, needles should be 1 inch to 1.5 inches for an adult and will be smaller for a child
This is about cellular health, not just lab results

Unlike oral supplements that may take weeks to absorb and are often less effective due to digestive limitations injectable B12 works quickly and efficiently

doi: 10.1016/0167-0115(84)90028-4