Thanks for your question! While all B vitamins have their own unique functions in the body, B vitamins in general act as a coenzyme. Thiamin, Riboflavin, Niacin, Folate, Biotin, Pantothenic acid, B6, and B12 all act as part of coenzymes - which are small molecules that combine with an enzyme and activate it. Without a coenzyme, the enzyme is not able to do its job. Enzymes in the body help to affect absorption of key nutrients (including protein, fats, and carbohydrates), metabolism, and excr...