I've been on Synthroid for years for thyroid issues that predate my cancer diagnosis. I tried switching to the generic version and found the results in managing my Hashimoto's Disease not the same despite the equivalent dosage. My endochrinologist switched me back to Synthroid and the symptoms disappeared. Despite similarities in the meds there are differences and just as with anything else they must react with your unique chemistry. The generic might work for some and is worth a shot, but talking with your doctor and monitoring symptoms would be prudent.