how much b12 injection do i need Are Vitamin Shots Right for You? Do You Still Need B12
Description
Mild redness that resolves within an hour indicates normal subcutaneous absorption

doi: 10.1021/acs.biochem.8b00775
Suited for dogs, cats, horses and cattle who are experiencing B12 deficiencies

The most common side effect is some soreness at the injection site, and you might notice your urine turning bright yellow (thats just the excess vitamins, particularly riboflavin, being excreted)
