Interesting... I was having a not-great night last night. Jangled nerves, borderline twitching, crazy-making RLS, couldn't sleep. From about 12:30 to 2:30 I tried some sublingual mB12, sublingual adoB12, and another shot of ado/methyl oil (my 4th for the day). The sublinguals didn't do much, the oil helped a little, but I was still going nuts. Then I remembered I took my son out for pizza last night: deep dish, thick crust, big fat rolled edge on the crust, and I inhaled half a large pizza. I've cut way back on bread products, and that's more bread than I usually eat in a week. I wondered if the @#%@#!! folic acid in the flour caused a problem... so I took 800mcg of methyl folate (in my gumline, to absorb quicker). Within 3-4 minutes I started getting the "aahhhhh" reaction I usually associate with B12, with muscles relaxing and tension draining out of my body. It didn't 100% clear up the problem, but it helped enough that I could fall asleep. So apparently methyl folate must have a much more direct effect on my symptoms than I realized. (I don't think it used to, because just mB12 alone used to calm my symptoms.) And apparently folic acid can block the methyl folate, just like @Freddd says. But a good shot of methyl folate seemed to overcome the folic acid. Does that sound right? I thought ALL flour in the US had added folic acid, but I think I was wrong. I have some King Arthur flour that doesn't list folic acid, but I don't know if they're required to list it. I have some bread (Dave's Killer Bread, great stuff) that says it has only 3% of folic acid RDA per slice. That would be 12mcg, and the FDA requires roughly 20mcg added folic acid per slice (40mcg per 100g), so I suspect the "folic acid" in the bread is natural folate from the wheat itself. So apparently the added folic acid is only in "enriched" flour, and if you're careful you can find bread products without it. But assume restaurants/etc probably use enriched-flour products.