Thanks so much for your quick response, mrsD. I began taking oral methylcobalamin as soon as I found out I was B12 deficient, which was about three months ago. Beginning with a dose of 2000 mcg daily, I gradually increased it each week until I reached 5000 mcg daily.

Currently I take 3000 mcg of methylcobalamin in the a.m. one hour before a meal, and another 2000 mcg in the p.m. about three hours before a meal. The brand I am using is Earth Sweet Chewables by Bluebonnet which I purchase through iherb. I realize that it may take as long as a year or two for any noticeable results, but I am in this for the long haul and I am a hopeless optimist!