I have ulcerative Colitis, which prevents me from properly absorbing B12. Last year I learned that my B12 was very low (136) and had injections to bring it up to 1100. At the time I didn't realize I needed to continue taking B12, so I just stopped. Within nine months it was back down to 214. Not wanting to go through injection therapy again, I asked my doctor if I could try taking oral supplements. He said I could try it but didn't have much confidence it would work. I took these pills every day (one per day) for three months and was tested again - my level was at 1350!!! I couldn't believe it and actually had them read it to me twice. I plan to continue taking these on a permanent basis. The cost of the injection therapy was approximately $800, so you can understand why I'm so thrilled that these work