N-Acetyl L-Cysteine (NAC)

 NAC (N-Acetyl-Cysteine) (250-650 mg). NAC is critical for making a key antioxidant called glutathione and for keeping Vitamins C and E in their active forms. It has been speculated that glutathione deficiency may be a major "root cause" in CFS. Although taking glutathione by mouth has no effect on blood levels (it simply gets digested), taking NAC, glutamine (1,000 mg/day, which also helps bowel healing), and glycine (500-1,000 mg/day) plus vitamin C can markedly increase glutathione levels. Supplementing these three amino acids is especially important in CFS, as NAC, glutamine, and glycine levels can decrease by 30-50 percent in this disorder. For NAC, I recommend 650-1,000 mg daily for 3-4 months and then 250 mg a day for maintenance. Low glutathione levels may contribute to your immune dysfunction, including low "natural killer cell" activity, as glutathione protects your immune system from harm.

NAC has other benefits as well. In one study, taking high dose NAC increased time to muscle fatigue by 30 percent while preventing a drop in glutathione.117 And, it may even help to protect the heart muscle during a heart attack.118 Antioxidants supplementation that includes NAC at doses of 600-3,000 mg/day even significantly decrease symptoms of obsessive compulsive disorder119, 120 which can trigger CFS/FMS. NAC also plays a role in detoxification.


117Matuszczak Y, Farid M, et al, "Effects of N-acetylcysteine on glutathione oxidation and fatigue during handgrip exercise," Muscle Nerve, 2005; 32(5): 633-8.

118Yesilbursa D, Serdar A, et al, "Effect of N-acetylcysteine on oxidative stress and ventricular function in patients with myocardial infarction," Heart Vessels, 2006; 21(1): 33-7.

119Lafleur DL, Pittenger C, et al, "N-acetylcysteine augmentation in serotonin reuptake inhibitor refractory obsessive-compulsive disorder," Psychopharmacology (Berl), 2006; 184(2): 254-6.

120 Ersan S, Bakir S, et al "Examination of free radical metabolism and antioxidant defence system elements in patients with obsessive-compulsive disorder,", Prog Neuropsychopharmacol Biol Psychiatry, 2006 May 6 [Epub ahead of print].

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