One more thing - when people who are deficient start taking folate and/or methylfolate, or both, very often they develop a functional potassium deficiency. Cells will start dividing more rapidly and doing what they )are supposed to do, which uses potassium, which can cause a deficiency because their body had adjusted to their deficient state.
Symptoms of low potassium can include fatigue (I developed severe fatigue), cardiac symptoms (irregular heartbeat.), muscle twitches and spasms. The symptoms very often will arise 2 - 3 days after starting the folate and methylfolate. Folate initially boosted my energy quite noticeably for 2 days (I'd already been taking methylcobalamin for many years) but on day 3 I was hit with horrible fatigue. Fortunately I had read about the issue with low potassium and was prepared. I started taking a potassium supplement and titrated up to 1000 mg over a couple of days, when the fatigue went away. I then found I had to take it all the time. I've been taking potassium gluconate for 8 years now, 200 mg with each meal and 200 more before bed
It's important not to take a large dose all at once, and take it in divided doses and work up to what works.
A simple thing to do if you start to experience what you believe is low potassium is to drink some low-sodium V8 or vegetable juice - it's high in potassium and low in sugar and drink a few or even several glasses and see if it helps. It might take a couple of hours. I don't think a couple of bananas would be enough.
People with ME/CFS very often are low in intracellular potassium even though their blood work looks fine. This post explains why:
http://forums.phoenixrising.me/inde...ded-in-methylation-treatmt.18670/#post-291422