Whenever I take Metafolin I get a severe histamine reaction. I talked to Rick about this and he said to try Folinic Acid. But I am curious if there is one possible mutation causing undermethylation whereby I would not even need to supplement any type of folic acid during my treatment protocol. Does anyone else have problems with metafolin? Literally every benefit I get goes away when I add in Metafolin. I'm not sure about folic acid. I have not tried folinic.