In March 2015, researchers reported that N-acetylcysteine (NAC) combined with behavioral therapy is effective for smoking cessation. The Centers for Disease Control and Prevention (CDC) estimate that 42.1 million adults in the U.S. are current smokers. Additionally, nearly seven out of ten current smokers report that they want to quit completely.

In this double-blind, randomized, controlled trial, 34 subjects with therapy-resistant tobacco use disorder received 3 grams per day NAC or a placebo for 12 weeks. The subjects also underwent concurrent smoking-focused group behavioral therapy. The investigators assessed the subjects for daily cigarette use, exhaled carbon monoxide levels, and quit rates defined as exhaled carbon monoxide level of less than 6 ppm. The investigators also evaluated the subjects for depression using the Hamilton Depression Rating Scale.

NAC supplementation significantly reduced the number of daily cigarettes compared to the placebo group. Additionally, the mean exhaled carbon monoxide level decreased by 10.4 ppm in the NAC group compared to 1.5 ppm in the placebo group. Furthermore, 47.1% of subjects in the NAC group were able to quit smoking compared to 21.4% in the placebo group. NAC supplementation also significantly reduced the Hamilton Depression Rating Scale scores.

The investigators stated, “These data show that treatment with NAC may have a clinical efficacy in tobacco use disorder. NAC combined with appropriate psychotherapy appears to be an efficient treatment option for tobacco use disorder.”

Reference: Prado E, et al. Redox Rep. 2015 Mar 2.