I use conjecture as part of my creative process. Thing is I do not pretend it is anything but conjecture.
Using those who share their experience on this forum it seems to me that of the three forms readily commercially available Methylcobalamin has the most profound effect.
As a person who is not experiencing the negative effects when injecting Methylcobalamin I wonder if the negative effects are from the Methylcobalamin are the results of the body being in distress due to the change in the body caused by quickly not being starved for cobalamin.
Physicians tend to see cobalamin malfunctions as starting on the day of diagnosis which is invalid and rather a sign that it has reached the point where the body is in distress. The determinant of what is distressful is often the personal opinion of human physicians.
I personally recently injected 2mg of Methylcobalamin 4 times a day and I concluded that this was currently to much for my body as it healed too fast and the result was my body needed too much rest and sleep.
So there are three forms of commercially available cobalamin. I wonder if what is most effective is the least stable of the forms as my body can use it more effectively.
I have yet to find any reliable data on the stability of the different forms. (expiration date is not usable data)
Using more conjuncture the stability in descending order is:
Cynocabalamin
Hydroxocabalamin
Methyelcobalamin
I am aware that I write from the perspective of a person who is healing weekly and had I read this post 6 months ago I would not have any interest in reading it. "Give me answers not conjecture" Profanity omitted.