B12 Injection Services Subtly You B12 Deficiency, Thyroid Disease and The MTHFR Connection Dr Hagmeyer Today is my vitamin B12 injection day. If you have Hashimotos disease (like me), it's really important to keep your vitamin B12 at optimal. Optimal is not just over the threshold, its Our bodies need vitamin B12 to maintain healthy red blood cells, nerves, and brain function. If a person has vitamin B12 deficiency (their body does not have enough vitamin B12), they can