The Short Answer
Most people take 600–1,800mg of NAC per day for general antioxidant and liver support, usually split into one or two doses with food. Some athlete and research protocols go higher, and clinical (hospital) use for paracetamol overdose uses far larger, medically supervised doses — but for everyday support the 600–1,800mg range is the commonly referenced window. FITCNT Liver Support delivers 1,250mg per daily serving, which sits right in that range.
Here's how to think about the right amount for you.
What NAC is doing at these doses
NAC (N-acetylcysteine) is a precursor to glutathione, the body's master antioxidant. Your liver leans on glutathione to handle oxidative stress from hard training, alcohol, and everyday metabolism — and glutathione gets depleted under load. The point of supplementing NAC is to keep the raw material topped up so your body can keep producing glutathione.
Typical dosing for athletes
- 600–1,200mg/day — a solid general range for antioxidant and liver support.
- 1,200–1,800mg/day — used when the goal is more aggressive antioxidant coverage, for example during heavy training blocks or a demanding supplement cycle.
Start toward the lower end, stay consistent, and adjust based on how you respond and any guidance from your healthcare professional. More isn't automatically better.
How and when to take it
- With food and water. This is gentler on digestion and easy to make a habit.
- Split larger doses across two meals if 1,200mg+ sits better in two halves.
- Consistency beats mega-dosing — daily use matters more than a big one-off amount.
How it pairs with TUDCA
NAC is often stacked with TUDCA because they work on different pathways — NAC fuels antioxidant defence, while TUDCA supports bile flow and liver-cell integrity. If you're building a liver stack, see NAC vs TUDCA: Do You Need Both?
Safety and tolerability
NAC is well studied and generally well tolerated. At supplement doses, the main reported effects are occasional mild digestive upset (nausea or loose stools), which taking it with food usually helps. As with any supplement, talk to your healthcare professional first if you take medication or have a medical condition. For the legal and regulatory picture in Australia, see Is NAC Legal in Australia?
How FITCNT doses it
FITCNT Liver Support delivers a disclosed 1,250mg of NAC per serving, alongside 650mg TUDCA, choline, alpha lipoic acid and zinc — third-party lab tested and banned-substance free, so a single daily serve covers a clinical NAC dose without a separate bottle. For the wider category, see our liver support buyer's guide.
The Bottom Line
For everyday antioxidant and liver support, 600–1,800mg of NAC per day with food is the practical range, with 1,200–1,800mg favoured during heavier training. Start low, stay consistent, choose a product with a disclosed dose, and check with your healthcare professional if you take medication or have a condition.
References
- "Acetylcysteine." LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. NIH. NCBI Bookshelf
- Tenório MCDS, et al. "N-Acetylcysteine (NAC): Impacts on Human Health." Antioxidants. 2021. PMC
- "N-Acetylcysteine." StatPearls. NIH. NCBI Bookshelf
This article is general information only and is not medical advice. Always consult your healthcare professional before starting any supplement. Not suitable for individuals under 18.