Severe post-exercise muscle soreness may be reduced by the amino acid N-acetyl cysteine (NAC). NAC is a precursor to glutathione, the body’s primary cellular antioxidant. Scientists in Brazil studied the effect of NAC supplementation on parameters of oxidative damage and inflammatory response after high-intensity eccentric exercise (EE). Twenty-nine participants were divided randomly in three groups to take either placebo, NAC or NAC plus placebo. After taking 750 mg per day for 14 days, participants performed 3 sets at 80% of their 1-rep max until exhaustion. For the next seven days, researchers monitored muscle soreness and markers of cell damage. Only the supplemented groups maintained high levels of interleukin 10 (IL-10), an anti-inflammatory marker, on the 7th day after the workout, suggesting that treatment with NAC might prevent muscle soreness after intense exercise.
Reference: International Journal of Sport Nutrition and Exercise Metabolism; 2008, Vol. 18, No. 4, 379-88.