I have taken both and there was no difference in the effect they had on me. My friends doctor will not even prescribe the generic Synthroid. I can say that the generic that I take has always been by the same manufacturer and I suppose it is possible that one generic might be different from another, but I don't think so. The key IMO is to make sure you get the correct labs. At least a TSH, free T4, free T3 and the antibodies. Get a Reverse T3 initially, but if it is mid-range I wouldn't worry about it anymore for at least 5 years or some other drastic event. Just from personal experience get all your hormones checked (if doctor will even do them all) and if you have 2 or more hormones that need supplementing do them one at a time. Adrenals should always come first though from what I understand and it does make since. If you ever need a little bit of cortisol you can always order Isocort from Amazon.com or many nutrition sites. I believe each pill has about 2.5 mg of cortisol, but keep your dosage to no more than 10 mg. and don't take it for more than 6 to 8 weeks and stopping until you have more labs or at least a month. Stabilizing your hormones take time (plenty of time), but they didn't get that way overnight and if you try to fix them overnight your going to end up spending a lot more money in the long run. This information is based on what I encountered and it is not intended to take the place of a doctors advice. I was always led to believe that an endocrinologist was the go to specialist here, but it was very wrong in my instance. I found a good MD that was also an Integrative Doctor and things went well. Good luck and please be as patient as possible.