Cyanocobalamin, a synthetic and highly stable form of Vitamin B12, is widely available as both an over-the-counter (OTC) supplement and a prescription-strength medication. Because it is cost-effective to produce, it is the most common form of B12 found in multivitamins and fortified foods.

You can find cyanocobalamin in various forms, including tablets, sublingual (under-the-tongue) nuggets, liquids, and gummies, at major retailers and health shops. How and when to take cyanocobalamin - NHS