Protein is important because it's needed for all necessary bodily functions. If you are looking to build lean (or bulky) muscle, lose weight, increase your immune system, etc. you need to make sure you are eating enough protein in your diet! Unfortun...
It is advised to only consume UP TO 400mg caffeine per day. Try to stay well below this recommendation to ensure optimal cardiac function!
Finding the right multivitamin is really important! Here's a few of my recommendations (different types too).