Acupuncture has been used in treating obesity even before 1975. Effect mechanism and beneficial effects of acupuncture treatment are unclear. Reactive oxygen species (ROS) are harmful by-products of human body metabolism. The oxidative effects of ROS are neutralized by the antioxidant capacity. Thiols are substantial antioxidant agents and found in cysteine amino acid. Cysteine residues form disulfide bridges, predictor of oxidant stress. Thiol-disulfide homeostasis is an important parameter associated with several disorders such as cardiac, endocrine, neurologic diseases. To date, the effect of acupuncture on oxidative stress and thiol-disulfide homeostasis in obese individuals has not yet been examined. Therefore, in this study, we aimed to investigate the effect of acupuncture for weight control on dynamic thiol-disulfide homeostasis. A total of 101 subjects who were being treated for weight control at our center (89 women and 12 men, body mass index (BMI)>= 22.48) were randomly enrolled in this study, and treated with car & body acupuncture. Body acupuncture is given manually. Ear acupuncture is given with a needle embedded within adhesive tape through performing acupressure by the patients three times per day. We measured the levels of thiol, any organic compound containing -SH group. Reduced thiol was represented with native thiol (-SH). Oxidized thiol (-S-S) was represented by disulfide. Total thiol was composed of sum of the native thiol and disulfide levels. We analyzed the differences between baseline BMI, blood native thiol, total thiol, and disulfide levels, and those after 10 weeks of acupuncture treatment. After acupuncture treatment, significant body weight and BMI reductions were observed. Mean body weight decreased significantly from 78.66 +/- 12.66 kg before treatment to 74.46 +/- 11.29 kg after treatment (p<0.001) and mean BMI decreased from 29.54 +/- 3.99 kg/m(2) before treatment to 27.98 +/- 3.68 kg/m(2) after treatment (p<0.001). Mean native thiol and total thiol levels increased significantly after acupuncture compared to before acupuncture. Disulfide levels insignificantly decreased. This is the first study to demonstrate that the beneficial effects of acupuncture in treating obesity are associated with improvements in thiol-disulfide homeostasis, an imbalance in which is associated with oxidative stress. Additional studies are warranted to investigate the mechanism or signaling pathways involved in the effect of acupuncture on obesity.