I hope someone who understands this will be able to go over the data at some point. There are a lot of knowledgeable people here so it seems likely that this will be of some use in the future. Did you mean folinic acid or folic acid? This thread is about folinic acid aka calicum folinate or 5-formyltetrafolicacid and not the folic acid that is in most supplements. From what I understand, folic acid would cause problems for people with MTHFR (not MTHFS) and/or DHFR polymorphisms. It would be a good idea for everyone to limit or avoid their folic acid intake because it doesn't serve any purpose and could still have a negative impact on people even if they don't have MTHFR or DHFR polymorphisms. Folinic acid on the other hand has been found to be beneficial for most people, but since some people are unable to process folinic acid we're trying to find out how prevalent this problem is and which genes are responsible.