Here's a few simple rules to follow when you look up supplements. Which might help you.
1. look for websites with the following.
Referances to independant testing, or it being explained by some regular guy, possibly an amateur BB for example, or sites like Pub Med, Uinversity sites etc etc.
None of these sites should contain weblinks to other sites, selling supplements, or offer you special order codes, 50% off etc etc.
Sites with such links / offers, you should NOT trust the info of, as they may contain massaged test results or omited side effects.
Some companies may not tell you a supplement has side effects, unless they're serious, like increased risk of miscarriages for example.
Mild liver damage off something, when used regulary for 10 or more years say, is not worth disclosing for some companies. A bit of a risk to profits, and also some reccomended levels on supplements might be higher than is needed, but is still safe to take, so you use more and buy more.
If a supplement is a designer one specific to one company, like No-Explode, or EAS Catapult as examples, as opposed to a basic NO or a Glutamine, or a Weight gainer say, don't trust the companies hype, trawl the internet, and if all you can do is find other sites like this, where people say yeah xyz product is crap or good or indifferent, that's your best chance of an honest appraisal.
Supplement users mostly have no reason to lie to you, like supplement companies might.
2. If a supplement is new, DON'T BUY IT. Give it 3-4 months, and then search the net. I bet 99% of the time by then, the inside track from Independant tests, regular, (non-industry) folks, or sites like this, will probably be available, so you get the real scoop on the "latest" supplement. Don't guinea pig test potential crap, let some other people out there do it for you, than get wise off their testimonies, it could pay off long term.
Hopefully that helps