There's two different levels of vitamin/nutritional supplements - professional grade and retail grade. The FDA does not regulate vitamin and supplement manufacturers so some companies cut costs by putting in lower quality ingredients and often don't even have the ingredients in them that they say they have! Professional grade supplements are made to GMP (Good Manufacturing Practice) and are mostly sold to health care professionals like the brands we carry. We order direct from the manufacturer, which eliminates the uncertainty about ordering from sites such as Amazon - where supplements might not have been stored correctly (thus losing their effectiveness) or even have in it what the bottle says it is. Let us know if you have any questions or if you have any special orders that you would like for us to get for you!