best place to inject b12 shot Vitamin Injection Site: Administering B12 Shots How to Use These 4

Bunce, D., M

A 22-gauge, 1.5-inch needle is usually adequate to reach most superficial muscles

Whats almost certainly NOT a B12 toxicity sign: bright yellow urine (thats B2), mild GI upset on the first dose (thats just a large pill), or feeling wired after taking a B-complex (thats more likely caffeine or other stimulants in your stack)

Bacterial overgrowth of the small intestine may lead to low serum B12 concentrations and vitamin B12 deficiency because the bacteria utilize vitamin B12 for their own metabolism so B12 cannot be absorbed by the body

The exception to this rule is the single preparation of the sub-Q or IM dose that exceeds the volume safely injected at a single site