Almost all literature and user experiences I've stumbled upon have suggested that antioxidants can help with certain symptoms of this disease. I haven't benefited from a single antioxidant, with the exception of Selenium, if you count it as an antioxidant. Antioxidant herbs and other supplements, even in moderate doses, tend to worsen my symptoms. My CFS/ME symptoms are light to moderate at most. What happens with antioxidant supplementation is usually this. A few days I can take whatever antioxidant and I notice moderate benefits, mostly a decrease of brain fog, certain myalgia and pain symptoms. After the first couple of days, I start to notice worsening. I get a flu-like feeling 24/7 that I don't normally have and notice a need for increased sleep without waking up refreshed. At the two week point I usually stop the experiment due to feeling so crappy. This year, I have in addition developed some POTS symptoms, daily palpitations and cold hands. All these symptoms with blood flow worsen with antioxidants, especially the cold extremities issue. My speculation is that this effect could be a result of at least three different actions: Antioxidants have many anti-inflammatory activities in the body, which typically results in reduced levels of pro-inflammatory cytokines and increased anti-inflammatory cytokines. In healthy people, this effect in moderation is probably helpful or at least does no harm, whereas with CFS/ME it may further imbalance the already imbalanced cytokine network and reduce the immune system's ability to fight infections. Antioxidants modulate nitric oxide and reduce reactive oxygen, which again can be very helpful for an average person for example dealing with hypertension, as I've read that endothelial NO synthase should increase with antioxidant use (source). With CFS/ME it is speculated that there is an existing imbalance with NO, and again antioxidants seems to make this imbalance worse at least for me, which would explain the worsening of cold hands and blood flow I get with supplementing. Lastly, it seems antioxidants can reduce mitochondrial biogenesis in humans following endurance training (article). With recent research pointing towards mitochondrial issues in CFS/ME, it would not be surprising if people with already dysfunctioning mitochondria would react worse to antioxidants, as endurance training could well be comparable to the stresses that CFS/ME puts on the body. Anyway, since most people, including healthy ones, tend to supplement with antioxidants in some form, the thought occurred to me that a subset of CFS/ME patients could subconsciously be making their disease worse with daily antioxidant supplementation.