Prothera-Klaire B12 liquid (Methylcobalamin) 1mg Methylcobalamin is the active coenzyme form of vitamin B12. In a liquid formula for rapid and efficient absorption. Supports red blood cell function, and neurological health. Recommended Use: Shake well before serving. Place 1 dropperful (1.0 mL), 1 to 5 times daily in the mouth and hold for thirty seconds before swallowing or as directed by a healthcare professional.