Hi all, I have been reading quite a bit about the above. I follow Dr Neil Nathan and others, and have noticed in his protocol he now only uses the one type of folic acid - (fol-pro) which is the 5L-methyltetrahydrofolate, no longer the 5-formyltetrahydrofolate. In the last version posted by Rich Van Konynenburg in 2012 he uses both types. Would love to hear other's expertise knowledge regarding this. Thanks so much.