But since many people here already do injections, it probably
is not so much of an issue.

The majority of injectable B12 is cyano version. If you are one
of the people who cannot convert it, then it doesn't work.

The oral active form methylcobalamin is so inexpensive and easy to use, and it has shown to be comparable to injection.

The only advantage I see for injection is for rapid intervention.
Often we see in the elderly when they are admitted to a long term care facility--very very low B12 levels. So injections are
given daily or every other day to get levels up quickly. Most of the B12 given by injection is cleared out of the blood within 72 hours. It is really a shame that the elderly might not even need the special care if they were targeted earlier. That is why NIH now recommends B12 supplementation for all people over 50, even if no symptoms exist yet.

There has always been a connection to low B12 and MS. In fact there were studies in Japan using mega mega doses up to 40mg a day for MSers-- That study is on PubMed. Many I believe are in the cloudy hard to diagnose category.

The anemia may not be due to low B12 or it may be. The type of anemia most often seen is a macrocytic anemia. MCV volume test reveals that. Anemia may be due to kidney problems, iron deficiency, malabsorption of iron, or hereditary reasons. If you are anemic it is often recommended to use a folic acid supplement, as well.