I guess this post will irritate some of you due to the fact that many similar threads probably have been started prior to mine. I still feel that I have to post this because I'm not sure whether my pretty severe headaches from hydroxocobalamin and methylfolate is something good (detox-effect) or something bad, which means that I need to stop immediately. Before I start writing about my experience with b12 and mthf I want to say that I probably don't have ME (I think I have mthfr, waiting on my 23andme-test). The reason I write on your forum is that you seem to be very knowledgeable about this. For a couple of weeks ago I started taking methylcobalamin and methylfolate (around 2 mg b12 and 1 mg methylfolate). It felt amazing for a week or so (maybe two) but then the effect stopped. A couple of days later I found this thread: http://www.longecity.org/forum/topi...tently-disappearing-during-alcohol-hangovers/ The guy who started the thread had the same problem as me but came up with a solution - to take hydrocobalamin instead of methylcobalamin. This has worked extremely well for him for over a year with close to no side effects. Since we both had the exact same dopamine-effect from hangovers and the same experience from taking methylcobalamin and methylfolate I really believed this could be the solution for me as well. So I ordered it and the when I took it I first felt great but then I got a harsh headache and a very dry mouth and felt tired. The headache and dry mouth remained to the next day. I took the hydrocobalamin and mthf the next day as well (probably not so clever). That was yesterday, today I haven't been taking it but the headache remains (the time is 11 pm in Sweden right now), a bit better now though. During this time I have been drinking high amounts of water but I have not been been required to pee very often at all, which probably indicates that the water is needed in my body. Before my headaches started I took 1 mg hydrocobalamin one time a day and around 300 mcg mthf two times a day. I have been eating really healthy for the last two month or so (bulletproof-diet). Mainly I want to get some information on what you think is causing this with my main question being if you believe that detox is causing this, which then would be a pretty good thing, or if it is something much more severe and bad happening to my brain when taking it. I hope my English was understandable and that someone had the willpower to read all this.