Theren is a big difference between natural and synthetic supplements. Natural vitamins are made from foods where as the others are made from coal tar by products and chemicals. Just b\'cos the bottle says \'natural\' don\'t fall for it. Read the labels. Every ingredient should be food. Most companies just put a little food in it so that they can call it natural. At the end of the day you get what you pay for. The better supplements are availble thru; health care practitioners. look up the \'Standard Process\' webiste. It has got some good research articles as well.