I came across this article on Cort's site & I think it is very relevant. Posting it here because it's related to gut/microbiome.One thing to notice it's at a genus (& not species) level & thus, it's not as simple as it looks. http://www.cortjohnson.org/blog/2016/02/21/gut-chronic-fatigue-syndrome-gender-differences/ Quoting some passages from the article, "The study suggested that bacteria of the Clostridium genera could be whacking women in a number of ways. Significant small to medium correlations between the abundance of Clostridium bacteria and fatigue, neurocognitive symptoms, sleep, immune impairment and total symptoms suggested that women with ME/CFS might want to steer their gut flora in a different direction. If Clostridium bacteria appeared to be a kind of kryptonite for women they were more like manna for men. So far as they were concerned, the more Clostridium bacteria the better; men with increased Clostridium bacterial levels had improved mood and a tendency for pain, gastrointestinal and energy production issues. The situation was reversed with Lactobacillus bacteria. Males with more Lactobacillus bacteria had more severe symptoms overall and more neurocognitive, neurosensory, pain and mood symptoms but women appeared to be affected by Lactobacillus bacteria not at all. Streptococcus bacteria continued the trend. Men with higher levels of Streptococcus bacteria tended to have more pain, worse sleep, more gastrointestinal symptoms, more problems with energy and more severe symptoms overall. Women, though, with higher levels of Streptococcus bacteria experienced less pain, neurosensitive problems and immunity impairments." Does any one have a list of D-lactate producers at species level? I will try to google it when I have some more time. In light of this info, it might be worthwhile to do, say a 2 week trial, following the suggestions in the article & then report here if one finds it useful.