I've heard the same; that generics are “allowed” more of a variance than brand name drugs. I think that with most drugs, it probably isn't a big issue. With thyroid replacement hormone though, a little bit makes a big difference as you saw in your numbers. I had a similar experience. I was on 100 mcg & had a TSH of 6.35. Was bumped to 112 mcg and 2 weeks later was at .79. Another 4 weeks later- at .68. I'm taking the brand name after reading various things like you mentioned. I don't know if it really matters, but I figure this journey is hard enough, why make it harder if I don't have to. Good luck & I hope it all works out well.
Also- I think the other problem with generics is that they can come from various manufacturers- even though you buy at the same pharmacy. So, although the same “dose”- their maybe be more of a variance not just among batches from the same manufacturer (although that's not likely) but also between the companies that produce them or maybe different fillers which would effect how T4 is absorbed in your body. At least with brand name you know you're getting the same amount and same fillers every time (barring some mistake in production).
Homeschooling mom to 4 wonderful boys!
Diagnosed with Graves Disease after my 4th baby- March 2012
Started on 5 mg. of methimazole daily for 7 weeks
Euthyroid at the end of those 7 weeks, but had to stop methimazole as liver enzymes were 8 times normal range.
Total Thyroidectomy- 6/15/12
Started Synthroid (brand name) 100 mcg. 2nd day after surgery for 6 weeks (TSH: 6.35 & free T4 in upper range and T3 just under mid- range).
Upped Synthroid to 112 mcg. 7/27/12
Euthyroid as of 8/10/12 on 112 mcg. Synthroid (TSH .79 and free T4 in upper range).