NACNAC: N Acetyl L Cysteine. NAC has several roles in addition to supporting glutathione production and liver detoxification. NAC regulates glutamate which decreases impulsivity and cravings. Some evidence supports NAC may be helpful in marijuana and alcohol dependence. 1. 2 grams for 2 capsules These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent any disease.