Vita-Jec B12 is approved as supplemental nutritive source of vitamin B12. Each mL of sterile aqueous solution contains 1000 mcg of B12. Readily available source of Vitamin B12.rnApproved for use in horses, dogs, and cats, this solution is available in 100, 250, and 500 mL sizes, and provides effective supplementation when normal dietary needs are not being met.We directly source prescription medications from manufacturers and wholesale distributors registered with the FDA and licensed by applicable state boards. Guaranteed genuine, and where applicable, backed by the manufacturer.