Here is a recent article from People's Pharmacy on generics.www.peoplespharmacy.com/2012/11/11/how-good-are-generic-drugs-1/
Here is one of the articles that cautions against generic thyroid meds.www.peoplespharmacy.com/2011/06/27/questions-about-generic-thyroid-medicine/
Synthroid, and my wife takes it, is an NTI or Narrow Therapeutic Index drug. This means if the dose is off in the generic, even a little, it could significantly affect the TSH level. Her doctors have been adamant that she NOT take generic equivalents of Synthroid, and she does not.