NAC (N-Acetylcysteine)
Also known as: N-Acetylcysteine, N-acetyl-L-cysteine, NAC
Effective Dosage
No established dose from provided studies for human supplementation
What the Science Says
NAC is a modified form of the amino acid cysteine that acts as a powerful antioxidant by neutralizing reactive oxygen species (ROS) and helping the body produce glutathione, one of its main internal antioxidants. In animal and cell studies, it has shown the ability to protect various tissues — including retinal cells, pancreatic cells, and lung tissue — from oxidative damage caused by radiation, toxins, and disease. It has also been used as a reference antioxidant compound in research to confirm that oxidative stress is driving a particular harmful effect.
What It Doesn't Do
The provided studies do not show NAC works as a standalone human supplement for any specific condition. No human clinical trial data is included in these papers. Don't assume animal or cell study results translate directly to benefits for healthy adults. Not proven to detox heavy metals in humans based on this data. Not shown to treat lung disease, cancer, or diabetes in people from these studies.
Evidence-Based Benefits
NAC acts as an antioxidant and glutathione precursor, with clinical evidence suggesting it may reduce contrast-induced acute kidney injury incidence (from 32.5% to 20% vs. control) when combined with hydration in coronary angiography patients, though statins outperformed it (PMID: 41701447). In a small RCT, NAC (1200 mg/day) increased serum antioxidant markers (SOD, TAC) and reduced pro-apoptotic gene expression in granulosa cells of infertile women with endometriosis (PMID: 41663453). A 44-patient RCT found NAC associated with changes in brain functional connectivity in Parkinson's disease patients, with some correlation to symptom improvement on UPDRS scores (PMID: 41619526).
Weak EvidenceEffective at: 500-1200 mg/day oral (clinical studies); IV dosing at 50 mg/kg/week also studied
Source: auto-research
Absorption & Bioavailability
Unknown based on provided studies — all data comes from animal models and cell cultures, with no human pharmacokinetic data included
Red Flags to Watch For
- All provided research is from animal models (rats, mice, Drosophila, zebrafish) or cell cultures — no human clinical trials are included in this data set
- High doses used in animal studies (e.g., 300 mg/kg/day in rats) do not directly translate to safe or effective human doses
- NAC is FDA-regulated as a drug (used in hospitals for acetaminophen overdose), and its status as a dietary supplement is legally contested in the US
- 665 supplement products registered in NIH DSLD suggests widespread commercial use that outpaces the human clinical evidence provided here
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06