There is a good article in Sports Illustrated on this week that IMO is a muct read for supplement users. I recommend it...it may open up some of yuor eyes to what you are buying...or more accurately the BS you are buying into. It think its called "What You dont know...just may kill you....."
Dont judge it by the title....there are a few exaggerated examples of supp dangers..and a few legit ones....id focus more on the lack or research ....ineffective supplements and bogus marketing and sales strategies these scumbags use. We are talking big name high dollar companies here guys (BSN , VPX, Muscletech and more) , Also pay attention to the section on supp manufacturer owners that are criminals. Thermolife for example (our boy ralph4u2c reps for them) the owner is a total rat in some large steroid cases...total scumbag. Anyway i recommend it as a good enlightening read.