How can I reduce my need for b12? I need to take atleast 4mg of methyl b12 injections daily for my symptoms to go away to be honest I think I need more but it's expensive. Would lithium help reduce the need for so much b12?
Four mg injected methyl-B12 daily is a huge amount. Perhaps there are some absorption problems which make such a dose necessary.
Methyl-B12 is only one of several co-factors required by various reactions along the methylation pathway and it may be that the depletion of other co-factors are the limiting ones in your case. These others are
vitamin B-2 (try 25 or 50mg daily),
zinc (try 30 to 50mg daily, no more) and perhaps
B-6 (try 25 to 50mg daily).
Of course
folate is important too and discussed frequently on this board. (Start with 500 to 1000 mcg methyl folate daily). Note that methyl-B12 and folate is the only instance in the body of two vitamins interacting closely.
A useful alternative pathway (not requiring B-12) becomes activated by taking
betaine (a few grams a day) and perhaps zinc too. It is not designed to be a main pathway and anyway is not found in the CNS but it may be useful to you.
You might find it interesting to check out Dr James Neubrander's advice on methyl-B12 for the children (with autism) he sees in his clinic. He has some unusual things to say about the concentration of injected methyl-B12 which I haven't seen elsewhere.
In his paper "Methyl-B12; Myth, Masterpiece, or Miracle", Neubrander writes a section under
"Myth: The Concentration Of The Methyl-B12 Solution Does Not Matter As Long As The Total Dose Remains The Same And That The Volume To Deliver The Equivalent Dose Is Adjusted." There is much more from him in this paper and others at
https://www.drneubrander.com/studies.php .