How can I be checked for intrinsic factor? Is it a blood test or something more complicated than that? Do regular laboratories do the test or will I need to do something with a special lab? I'm seeing my Endocrinologist in early October and usually get various blood tests before the appt.

Should I also get my other B vitamins tested? My folate levels are good, as are my Magnesium and other blood work I've done.

The more I think about the, the more I'm angry that none of my doctors thought to add this simple blood test to my panel until now. I started seeing a new GP and she added B-12 as an afterthought! I may have been deficient in B-12 for the past 15 years (I have had Hashimoto's since the birth of my second child 15 years ago).

Thanks for letting me know that I can take the B-12 and Synthoid together. That really helps.

This morning I took my Synthroid early (half awake in bed) and later after I got up, I took 1,000 mcg of B-12 sublingual, as well as my regular B-complex (which I now see has 400 mcg of B-12). Within a half hour I began to feel rather shaky. I suppose it will take some trial and error to find the right dosage, at least for first thing in the morning. Perhaps taking 1400 mcg all at once is too much for me at the moment. Should I divide it up and take it a couple of times per day? I know that I shouldn't take it too late in the day, as it is "activating."

The sublingual B-12 I got at Walgreens is Cyanocobalamin (sp?) and is made by Nature's Bounty. My B-Complex has 400 mcg Methylcobalamin and is made by Pure Encapsulations. It also has 20mg of B-6 (10 mg of Activated B-6 and 10 mg of non-Activated). I could list all the ingredients if you want. It's supposed to be a very good brand, but I would appreciate advice from you guys on a good brand of each of these (B-12 and a B-complex). I know that being on the birth control pill can additionally sap me of B vitamins, so that might be an additional factor in this.

I noticed that someone had said they were taking Jarrow. I know that is a good brand. I have an excellent health food store in town that I could get that from (or just go online).

Thank you all so much for your advice and help!