N-Acetylcysteine

N-Acetylcysteine (NAC) has demonstrated promise in preventing and reducing the severity of colds and flus. Andrew Huberman discussed its effectiveness, referencing a study in which NAC significantly lowered the incidence of clinically apparent flu compared to a placebo group (25% vs. 79%). He explains that NAC works primarily by increasing glutathione, a potent antioxidant beneficial for immune health. It is currently available over the counter in the U.S., with typical preventative dosages around 1200 mg per day, split into two doses of 600 mg each. However, when used during an active cold, dosages could be increased to 900 mg three times per day, though it is advised not to take it close to bedtime as it can disrupt sleep due to increased mucus production 1.

Additionally, NAC is utilized as a mucolytic agent, helping to alleviate congestion by thinning mucus. This makes it an effective alternative to over-the-counter decongestants, which can cause rebound congestion and have no additional health benefits. A cited study from 1997 noted that long-term administration of NAC (600 mg twice daily for six months) reduced the likelihood of contracting influenza 2.

While these findings are promising, more research, particularly randomized controlled trials, would help validate NAC's efficacy more robustly 3.