Hi Freddd, yes I was considering that too. It is possible that many of our fluctuating symptoms tie into this. The way to test it is to have blood samples taken at home during crashes due to weakness, or diarrhea or constipation. With a little more work this could justify a methylation/gut/brain crossover thread. I wonder if there is any published evidence of this kind of thing? Bye, Alex PS Here is a link to a discussion of low total body potassium: http://sacfs.asn.au/medical/adelaide_uni_research_3.htm Fifty-one subjects with CFS only (29) or myalgia/fatigue (22) were studied with a TBK a full biochemical profile and the results were analysed for these 2 groups. The CFS group with fatigue only, showed a significant reduction in the level of TBK and in one half of these the reduction in TBK was greater than 10% of the normal estimated for age weight and sex. The serum potassium levels were normal in all subjects. Of course under the working hypothesis they might not see transient loss of potassium in blood. It has been said elsewhere that the potassium issue may be linked to patients with CFS but who do not have fibro.