Overview of vitamin B What is vitamin B complex and what does it do? Vitamin B is the name for a group of eight B vitamins that are essential for the healthy functioning of the body, while vitamin B complex is a supplement containing all the B vitamins you need each day.1 Vitamin B complex usually contains these nutrients:2 thiamin (vitamin B1) riboflavin (vitamin B2) niacin (vitamin B3) pantothenic acid (vitamin B5) pyridoxine (vitamin B6) biotin (vitamin B7) folic acid (vitamin B9) – this is the synthetic version of folate cyanocobalamin (vitamin B12) Each...