Take the 5mg oral Methylcobalamin on an empty stomach daily and you should see a marked improvement.

The injections are typically cyano form, and some people cannot convert it to active methyl form so by taking the methyl in the first place you bypass that problem.

You can buy methylcobalamin online for very low prices. It is not expensive. I use Puritan's version, and it works out to $4.00 a month.
But other places have it, like iherb.com, swanson's, and vitacost to name a few. Most local stores still don't carry it, but that is changing as well. Expect to pay more for it in a store however.

This is the B12 thread: Lots of medical information on this link:
http://neurotalk.psychcentral.com/thread85103.html

In the US the cut off for normal now is 400pg/ml
The lab ranges still reflect very low numbers however, and when doctors are not educated on the new treatment protocols, then the patients really suffer even when tested.

This is a list of how to convert from SI (international units) to
conventional US units
http://www.unc.edu/~rowlett/units/sc...ical_data.html

If you cannot convert cyanocobalamin in injections, it will still float around in the blood and show up on tests. Even when inactive. It will be unable to work in the tissues however.

MMA test and homocysteine test will show if B12 is actually working. You might want to have the MMA test at least to see.
Otherwise the only other test for genetic failure of methylation is a DNA test. Called the MTHFR test.

With what is known today about methylation and B12, no doctor should be cavalierly depending on injections. Even at once a month they can be failing you.