Recently Consumer Reports had a lengthy article regarding the supplement industry. Here is the main article and here is a list of supplements to avoid.. The main take-aways were:

The supplement industry isn’t strictly regulated by the FDA, though most consumers assume that it is. That doesn’t mean that all supplements are a sham, but it does behoove the consumer to do the research. Groups like Consumer Labs provide information on content and safety of various brands.
When it comes to choosing supplements- again, do your own research- utilizing resources like Examine.com can help you choose both safe and effective supplements. The folks at Examine.com synthesize the available scientific research on given supplements and ingredients and they do a pretty darn good job. A little bit of digging can save you a little bit of moolah.
The “natural” label is on a bottle can literally mean nothing. Companies can slap that label on anything without any oversight from a governing body that defines what that term means (arsenic is “natural…).
Companies are required to print the ingredients (mostly, there are loopholes like “proprietary blend” that muddy the water a bit) on their bottles, however they don’t necessarily have to put how much of each ingredient is in the supplement. For example, caffeine could constitute most of an “energy” supplement even though the consumer may think their getting B vitamins, gensing, and green tea extract.
Consumer Reports, as an experiment, created their own supplement. They ordered the ingredients, the pill-making supplies (capsules and a machine that fills the capsules), bottles, and created labels all for about $190.00. Granted, any company that creates and sells supplements must have an FDA-approved facility (though, again, that doesn’t necessarily include the contents of said supplements) and I doubt bigger companies do such things, but it just goes to show that how easy it is for kinda anyone to make and market a supplement.

There can be a time and place for these guys, but make sure you have a solid diet first.

Quite frankly, eating a healthy diet with plenty of variety will go a long way to supplying what you need on a regular basis. I’ve written about it before, supplements can have their place within the context of a healthy diet- I’m certainly not anti-supplement- but they are to be treated as such, supplements not replacements. I simply urge everyone to be discerning consumers.