I found out a few days ago that I'm MTHFR (+/-), but I don't quite understand how folic acid affects me. I made a recovery during a period where I was taking 1600 mcg of folic acid and no other folate and no B12. When I tried taking 100 mcg methylfolate last fall I felt the effects even though I was taking 1500 mcg of folic acid. Now it's certainly possible that taking the folic acid made me deficient in methylfolate which is why I had a strong reaction to the methylfolate, but the folic acid certainly didn't "block" methylfolate as some people suggest. I took 1500 mcg of folic acid 100 mcg methylfolate for 5 weeks and the symptoms persisted. I didn't know what methylation was so I didn't take any potassium, but that still doesn't explain my reaction which was clearly overmethylation. I wasn't taking any sublingual B12 during that period either since as I said earlier I didn't know what methylation was. The reason I was taking methylfolate is because Jarrow changed the formula of their B Right b complex which I had been taking for over a year. I've stopped all my supplements with folic acid, but I still eat food sometimes that has folic acid in it. Since I don't experience symptoms from folic acid do I really need to completely eliminate it? Or is just severely limiting it enough? Also, does it make a difference whether or not I have a DHFR polymorphism in addition to MTHFR. I don't think DHFR has been mapped out yet so we don't really know which SNPs are problematic.