Unlike Canada and Australia, the United States does not regulate supplements. According to the FDA, supplements are considered a food-grade product and are held to the same health department standards as restaurants. The facility has to be clean and maintained, and the ingredients can't be harmful. But that is it!
But what really blows me away is that what is on the label of a supplement does not have to be in the bottle!! In a recent study, researchers found that over half of supplements do not even properly disintegrate. So if it isn't disintegrating, then it isn't dissolving, then how are the needed nutrients getting into your system to be used? I have heard nurses say that they call a certain well-known over the counter multi-vitamin "bed pan bullets" because you can still read the name on the tablet when it is passed through the body. We literally flushed thousands of dollars down the toilet.
Proper disintegration is just one factor!! Another study showed that when tablets were tested, two tablets in the same bottle could have a different amount of nutrients. This is why taking a pharmaceutical-grade supplement is so important! Pharm-grade products have very stringent regulations and inspections and their potency has to be guaranteed. Call your product manufacturer and ask if you can get a potency guarantee in writing. If they don't give a written guarantee I know one company that does!