It acts as a selective inhibitor of nicotinamide N-methyltransferase (NNMT), an enzyme expressed in multiple tissues including adipose tissue and the liver that plays a role in cellular energy metabolism and fat storage
Vitamin B12 comes in many forms, however, sublingual B12 (taken under the tongue) is one option (NIH, 2020)
If you add 2ml of bacteriostatic water to a 10mg vial, you have 5,000mcg per ml
Its a genuine open question
If it hasnt and youre exhibiting symptoms like fatigue, numbness, or anemia, ask if a B test is needed
Evidence-based : Ensuring clinicians understand the difference between serum B12 levels and clinically active B12 stores, and other suitable tests to determine deficiency as well as symptom resolution with sufficiently frequent treatment