I don't think I "fit" the definition and symptoms of chronic fatigue syndrome (e.g., I don't fulfill all the medical criteria, symptoms seem to sway relative to hormones and possible influence on thyroid, have tried most supplements for CFS with no benefit), but I do have post-exertional malaise when I exercise more than a little bit, often feeling worse the entire next day in terms of fatigue. I don't think I have easy muscle soreness, but this was something that seemed to start happening over a year ago when I started getting PEM, despite being on testosterone replacement. I don't get usual lactic acid symptoms, like soreness. That said, I have been drinking (and loving more than I thought) kombucha along with taking a good probiotic supplement, which seems to help my gut motility (and therefore, important for me, my estrogen). This kombucha drink has 25 mg of lactic acid. I haven't noticed any direct or obvious connections between drinking it and an increase in symptoms, BUT: Does anyone know if this is too much or a bad thing in general to consume lactic acid if I have chronic fatigue (but not necessarily diagnosable CFS, likely fine lactic acid levels but possibly not)?