N-Acetyl Cysteine (NAC)
Glutathione precursor; supports liver detox and respiratory health.
By Suplagen Team · Updated
What it is
NAC is a stable form of the amino acid L-cysteine. It's a direct precursor to glutathione, the body's master antioxidant.
How it works
Replenishes intracellular glutathione; supports Phase II liver detoxification and mucolytic activity in airways.
What the evidence says
Strong evidence as glutathione precursor and mucolytic; moderate evidence for liver support and antioxidant defense.
How much to take
The catalog range is 600 to 1,800 mg daily, and 1,800 mg is the ceiling. 600 mg is the classic single dose; the top of the range is usually split into 2 or 3 doses because higher single amounts cause GI upset.
Its strongest evidence is as a glutathione precursor and a mucolytic; for antioxidant defense and liver support the grade is moderate. Dose to the purpose: 600 mg covers the everyday case.
When and how to take it
Morning, on an empty stomach for best absorption, and separated from mineral supplements. If you take a higher dose, split it: 600 mg twice daily is the common shape.
The catalog suggests pairing it with vitamin C to support glutathione recycling. There's no timing conflict between them.
Who should skip it
Two cautions and one hard interaction. Active bleeding is a caution, and a rare bronchospasm has been reported in people with asthma. Nitroglycerin is a high-severity interaction; anticoagulants are mild and activated charcoal moderate. Pregnancy safety isn't established.
Safety Notes
- May cause GI upset at higher doses. Consider taking with vitamin C to support glutathione recycling.
- Use caution with: active bleeding (caution), asthma (rare bronchospasm reported).
- nitroglycerin: May potentiate effects causing severe hypotension; avoid concurrent use.
- anticoagulants: May have mild antiplatelet effects.
- activated charcoal: Charcoal reduces NAC absorption; separate dosing.
Common questions
What is the best time to take NAC?
Morning, on an empty stomach, away from minerals. If you split a higher dose, the second one goes mid-afternoon, still away from meals if you can manage it.
Should I take NAC morning or night?
Morning. Nothing in its profile favors evening dosing, and the empty-stomach rule is easiest to keep first thing.
Is NAC 600 mg twice daily too much?
No. 1,200 mg total sits inside the 600 to 1,800 mg range, and splitting it is exactly how the catalog suggests taking higher amounts.