The difference is the formulation pure B12 vs B12 + MIC lipotropic compounds
The documented per-dose amounts (150 mcg from the 10 mg vial
Methionine plays a critical role in the metabolism, inositol stimulates the removal of fat from the liver to prevent fat storage, and choline prevents cholesterol and fat build up in the body
References Heffernan, M., Summers, R.J., Thorburn, A., Ogru, E., Gianello, R., Jiang, W.J., & Ng, F.M
Decrease dose if: Experiencing consistent side effects (headaches, fatigue, GI disturbance), achieving satisfactory results at current dose with no need for escalation, or cost considerations favor using minimum effective dose
To prevent this, use sterile saline and single-use needles, and make sure they only touch the B12 and your skin