How does N-Acetyl cysteine (NAC) work for treating cold symptoms?

NAC may ease cold symptoms by supporting antioxidant defenses and loosening airway mucus.

• Glutathione: NAC is a precursor to glutathione, an antioxidant involved in reducing reactive oxygen and nitrogen species, which rise during infection. 1
• Mucus and congestion: NAC acts as a mucolytic: it loosens mucus so it can flow more readily from the lungs, nasal passages, and sinuses, which may relieve congestion and sinus pressure. 2
• Influenza findings: In one study, 79% of the placebo group developed clinically apparent influenza symptoms, compared with 25% of the NAC group. 3
• Dose and timing: For cold symptoms, the described dose was 900 mg three times daily, taken earlier in the day and not close to bedtime, since increased mucus flow and post-nasal drip disturbed sleep. 4