Glutathione testing is not a standard wellness assessment for most healthy adults, and blood measurements may not reflect levels in every tissue
One cluster analysis of 131 ME/CFS patients diagnosed according to the Fukuda criteria revealed that 34% of patients experienced sympathetic symptoms with dysautonomia (and were associated with more severe disease severity), 5% from sympathetic symptoms alone, 21% parasympathetic, and 40% struggled with sympathovagal balance (331)
An increase in plasma antioxidant capacity following the intake of polyphenol-rich foods, such as apples, tea, blackcurrants, and red wine, indicates that polyphenols can cross the intestinal barrier and exert systemic effects (113)
42 Another RCT studied cyano-B12, 1500 g three times per day for 2 weeks (route not reported), in patients with seasonal affective disorder and found no improvements in either the B12 or the placebo group