N-Acetyl Cysteine (NAC)
N-acetyl cysteine (NAC) is a sulfur-containing amino acid derivative that serves as the most efficient precursor to glutathione, the body's master antioxidant. Originally developed as a pharmaceutical mucolytic agent to break down mucus in respiratory conditions, it has gained widespread use as a supplement for antioxidant support, liver protection, and detoxification.
Expert Evidence
8 references from 2 experts
“As a preventative, the dosage is about 1,200 milligrams per day divided into two different dosages of 600 milligrams each. If you already have a cold, I took 900 milligrams three times per day, avoiding intake close to sleep because it did disrupt my sleep.”
How to Prevent & Treat Colds & Flu
2:02:063 references in 3 episodes from 2024–2025
Huberman personally takes NAC to support glutathione production and detoxification, initially starting it after discovering elevated mercury levels in his blood. He recommends 1,200 mg/day (split into two 600 mg doses) as a preventative, and 900 mg three times daily when sick, noting it can disrupt sleep if taken too close to bedtime. No cautions beyond sleep disruption are discussed.
“For me, as of right now, I wouldn't take more than 1.5 grams twice a day until we've got further longer-term data. And I'd only start these supplements once I reach the age of 50 years or older.”
NAC (& Glutathione) Crucial New Research
6:225 references in 3 episodes from 2021–2023
Brad Stanfield views NAC primarily as an aging intervention for adults 50+, citing RCT evidence that glycine+NAC supplementation improves glutathione levels and mitochondrial function in older adults. He has not discussed personal use, and cautions against use in those with bleeding disorders or on blood thinners.
Benefits
Glycine and NAC supplementation in older adults improved glutathione deficiency, mitochondrial function, physical function, and waist circumference in a randomized controlled trial.
Best Practices
Recommends at least 1,200mg daily for clinical benefit, with an ideal dose around 1.5g twice daily. Advises waiting until age 50+ to start and not exceeding 1.5g twice daily until longer-term data is available.
Cautions
NAC can thin the blood, so people with bleeding disorders or on blood-thinning medications should avoid it.
Side Effects
- Nausea and gastrointestinal discomfort
- Diarrhea at higher doses
- Unpleasant sulfurous smell or taste
- Potential blood-thinning effects