I take 1000 mcg a day. There are a couple of brands available on Amazon. One is KAL, the other is Superior Source. Each has a 500 mcg pill. I take two a day - one in the morning and one in the afternoon.

There was a Japanese study some years ago that evaluated a 45mg dose (not 45mcg!), so you might see that somewhere, but other studies I've seen say that a much lower dose is fine. Dr. McCormick doesn't recommend this mega dose at all. His own supplement contains 1000mcg.