NAC (N-Acetyl-L-Cystein)
Overview
NAC (N-acetylcysteine) is the acetylated form of L-cysteine and a direct precursor to glutathione (GSH), the body's primary antioxidant. Established medical uses include acetaminophen overdose antidote (restoring hepatic glutathione) and mucolytic therapy. Widely marketed as a supplement for antioxidant and liver support. The FDA determined in 2021 that NAC cannot legally be sold as a dietary supplement in the US. Generally well tolerated at typical supplement doses; may interact with warfarin and serotonergic substances. Mineral interaction: NAC binds copper (Cu2+) via its thiol group and can mobilize zinc into urinary-excretable complexes. At standard oral doses of 600mg/day, clinical studies show no detectable effect on zinc or copper metabolism in humans (PMID 2276385, PMID 1529808). The effect becomes plausible at doses above approximately 800 to 1200mg/day based on in vitro and animal data (PMC7696987), but direct human evidence at supplement doses in this range is lacking. Very high IV doses (20g/day, as used in acetaminophen poisoning treatment) are associated with increased urinary zinc excretion.
Dosage
600 mg · Any time · Can take on empty stomach
Key Interactions
14 verified interactions found
NAC thiol group can chelate iron, reducing absorption. Timing separation recommended.
Separate by 2 hours. Iron empty stomach, NAC separately.
View details →NAC is the rate-limiting precursor for endogenous glutathione synthesis. Supplemental glutathione provides direct GSH. NAC sustains intracellular levels while oral GSH provides immediate availability.
Can combine. NAC provides long-term GSH support, oral glutathione for acute boost.
View details →NAC has mucolytic and biofilm-disrupting properties that can enhance probiotic colonization. Probiotics support gut barrier integrity; NAC reduces gut oxidative stress.
Combine for gut health. Probiotics on empty stomach, NAC with or without food.
View details →Both support liver function through complementary mechanisms. NAC replenishes hepatic glutathione; Silymarin (Milk Thistle) stabilizes hepatocyte membranes and promotes liver cell regeneration.
Combine for liver support. Both can be taken with meals.
View details →NAC reduces oxidative stress via glutathione; Curcumin reduces inflammation via NF-kB inhibition. Complementary anti-inflammatory and antioxidant support.
Combine for inflammation and oxidative stress management.
View details →What Experts Say
“supplementing with an acetylcysteine and liposomal glutathione both of which are intended to increase glutathione levels in the body and brain may reduce some of alcohol's damaging effects and aid in detoxification processes in the liver”
Rhonda Patrick discusses NAC (N-acetylcysteine) as a glutathione precursor for alcohol-related liver protection. She notes that supplementing with NAC and liposomal glutathione may reduce some of alcohol's damaging effects and aid liver detoxification, while describing the evidence as speculative.
Scientific Sources
- Source
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- Oral NAC 600mg/day: no detectable influence on zinc, copper, calcium, magnesium, iron excretion
- NAC at supplement doses does not affect zinc metabolism; high IV doses (20g/day) may increase urinary zinc
- In vitro + animal: NAC reduces cellular Cu and Zn concentrations via thiol chelation — preclinical only
- NAC chelation
- Iron absorption
- NAC + Probiotika combination study (PMID:37367942)
- NAC + Probiotika combination study (PMID:35489181)
- NAC + Milk Thistle combination study (PMID:39497389)
- NAC + Milk Thistle combination study (PMID:36129244)
- NAC + Milk Thistle combination study (PMID:24251357)
- NAC + curcumin antioxidant synergy (2023)
- NAC curcumin combination study (2025)
- N-acetylcysteine + curcumin review (2024)
- PubChem Compound 12809
Frequently Asked Questions
What is NAC (N-Acetyl-L-Cystein) used for?
NAC (N-acetylcysteine) is the acetylated form of L-cysteine and a direct precursor to glutathione (GSH), the body's primary antioxidant.
What is the recommended dosage for NAC (N-Acetyl-L-Cystein)?
600 mg. Any time. Can take on empty stomach.
Does NAC (N-Acetyl-L-Cystein) interact with other supplements?
NAC (N-Acetyl-L-Cystein) has 14 verified interactions. Top: Eisen, Glutathione (GSH).
When is the best time to take NAC (N-Acetyl-L-Cystein)?
Any time. Can take on empty stomach.
Is NAC (N-Acetyl-L-Cystein) safe to combine with other supplements?
Always check interactions before combining supplements. Use VitalStack to verify your full stack for free.
Check how NAC (N-Acetyl-L-Cystein) fits your full stack
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Check Your Stack →Not medical advice. VitalStack is not a medical device. For personalized health recommendations, consult a healthcare provider.