N-Acetylcysteine
Also known as: NAC, N-Acetyl-L-Cysteine, N-acetylcysteine
This ingredient is classified as unclassified risk (GIRI score: 2.5/10).
Safety Profile
Information not yet available for this ingredient profile.
Interactions
Information not yet available for this ingredient profile.
Evidence and Scientific Findings
Ingredient Overview
NAC is a precursor to glutathione and is used medically as an antidote for paracetamol overdose. As a supplement it is generally safe at 600–1200 mg/day. High doses may cause nausea, vomiting, and headache. It can interact with nitroglycerin, activated charcoal, and certain chemotherapy agents. Inhalation forms can cause bronchospasm.
Biological and Chemical Classification
Information not yet available for this ingredient profile.
Mechanism of Action
Information not yet available for this ingredient profile.
Clinical Evidence of Effectiveness
Information not yet available for this ingredient profile.
Pharmacokinetics
Information not yet available for this ingredient profile.
Recommended Dosage
Information not yet available for this ingredient profile.
SETI — Scientific Evidence Transparency Index
Executive Summary — Ingredient Assessment
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or RCT)
- Main clinical benefit observed: Antioxidants
- Evidence consistency: High consistency across studies (100%)
- No significant safety signals identified in the reviewed literature.
The available scientific evidence for N-Acetylcysteine indicates notable safety signals that warrant caution. Use should be considered carefully and monitored, particularly in sensitive populations or alongside other medications.
Total SETI Score
High risk| Evidence quality | 10/40 |
| Evidence consistency | 20/20 |
| Safety signals | 0/20 |
| Study recency | 10/10 |
| Evidence transparency | 10/10 |
Evidence Summary
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or systematic review)
- 0 studies identified benefits or no safety concern (GREEN)
- 10 studies reported limited or advisory safety evidence (YELLOW)
Evidence Policy
Only peer-reviewed scientific literature indexed in PubMed or comparable databases is included in this evaluation. Commercial websites, blogs, and marketing materials are excluded. All references include direct traceable links to source documents.
Last updated: 26 მარ 2026, 13:59
Evidence Distribution
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Observational / other LOW evidence YELLOWTransplant-free survival in dengue-associated acute liver failure: Current evidence and future directions. ↗Madhwani A et al.. Transplant-free survival in dengue-associated acute liver failure: Current evidence and future directions.. World J Virol. 2026. PMID:41884454.PMID 41884454 ↗Journal World J VirolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41884454/
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Observational / other LOW evidence YELLOWDifferential Radiosensitivity in T-Cell Subsets: Metabolic and Antioxidative Mechanisms Underlying Nau00efve T-Cell Vulnerability. ↗Lin LY et al.. Differential Radiosensitivity in T-Cell Subsets: Metabolic and Antioxidative Mechanisms Underlying Nau00efve T-Cell Vulnerability.. Radiat Res. 2026. PMID:41881374.PMID 41881374 ↗Journal Radiat ResYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41881374/
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Observational / other LOW evidence YELLOW3D-QSAR study for the development of chalcone-based inhibitors targeting ovarian cancer cells with experimental validation. ↗Valenzuela-Valderrama M et al.. 3D-QSAR study for the development of chalcone-based inhibitors targeting ovarian cancer cells with experimental validation.. Front Pharmacol. 2026. PMID:41878339.PMID 41878339 ↗Journal Front PharmacolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41878339/
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Observational / other LOW evidence YELLOWThe role of N-acetylcysteine and glutathione in the management of Parkinson's disease: a systematic review of oxidative biomarkers and clinical outcomes. ↗Mohammed I et al.. The role of N-acetylcysteine and glutathione in the management of Parkinson's disease: a systematic review of oxidative biomarkers and clinical outcomes.. Amino Acids. 2026. PMID:41874704.PMID 41874704 ↗Journal Amino AcidsYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41874704/
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Observational / other LOW evidence YELLOWOxidative stress and the therapeutic potential of dietary antioxidants in polycystic ovary syndrome: a narrative review. ↗Amer NA et al.. Oxidative stress and the therapeutic potential of dietary antioxidants in polycystic ovary syndrome: a narrative review.. J Ovarian Res. 2026. PMID:41872939.PMID 41872939 ↗Journal J Ovarian ResYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41872939/
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Observational / other LOW evidence YELLOWCombined N-acetylcysteine and tranexamic acid attenuate acidosis and fibrinolysis in a swine polytrauma model. ↗Cardoso JMDF et al.. Combined N-acetylcysteine and tranexamic acid attenuate acidosis and fibrinolysis in a swine polytrauma model.. J Trauma Acute Care Surg. 2026. PMID:41870350.PMID 41870350 ↗Journal J Trauma Acute Care SurgYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41870350/
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Observational / other LOW evidence YELLOWAssociation of vitamin D and N-acetylcysteine supplementation with anxiety, cognition, and biomarkers in generalized anxiety disorder: a retrospective cohort study. ↗Zhang Y et al.. Association of vitamin D and N-acetylcysteine supplementation with anxiety, cognition, and biomarkers in generalized anxiety disorder: a retrospective cohort study.. Am J Transl Res. 2026. PMID:41868894.PMID 41868894 ↗Journal Am J Transl ResYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41868894/
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Observational / other LOW evidence YELLOWParaquat Peril: A Retrospective Study from the Frontlines of a Quaternary Care Hospital in South India. ↗Neeraj GP et al.. Paraquat Peril: A Retrospective Study from the Frontlines of a Quaternary Care Hospital in South India.. Indian J Crit Care Med. 2026. PMID:41868073.PMID 41868073 ↗Journal Indian J Crit Care MedYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41868073/
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Observational / other LOW evidence YELLOWNF-u03baB modulates ROS/JNK signaling to attenuate apoptosis in largemouth bass hepatocytes during recovery from heat stress. ↗Mao W et al.. NF-u03baB modulates ROS/JNK signaling to attenuate apoptosis in largemouth bass hepatocytes during recovery from heat stress.. J Therm Biol. 2026. PMID:41864100.PMID 41864100 ↗Journal J Therm BiolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41864100/
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Observational / other LOW evidence YELLOWExperimental evaluation of N-acetylcysteine against doxorubicin cardiotoxicity in rats. ↗Tola HT et al.. Experimental evaluation of N-acetylcysteine against doxorubicin cardiotoxicity in rats.. BMC Pharmacol Toxicol. 2026. PMID:41863011.PMID 41863011 ↗Journal BMC Pharmacol ToxicolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41863011/
Score Transparency
0 of 10 approved references (score saturates at 10). More peer-reviewed studies = stronger evidence base.
Method: Q = number of approved references ÷ 10 (capped at 1.0)
Limited — mostly case reports or animal studies
Method: L = mean study-level weight across approved references. Level 1 (meta-analysis / systematic review) = 1.0; Level 2 (RCT) = 0.8; Level 3 (cohort/case-control) = 0.6; Level 4 (case report) = 0.4; Level 5 (animal / in-vitro) = 0.2.
Mixed or neutral — roughly equal benefit and risk signals
Method: D = (sum of risk-scored references − sum of benefit-scored references) ÷ total evidence score, then scaled from [−1, 1] to [0, 1]. 0.0 = pure benefit; 0.5 = neutral; 1.0 = pure risk.
One or more monitoring-level safety signals active
Method: S = 0.5 (neutral baseline) + sum of active signal severity deltas ÷ 10. Severity deltas: Critical = +2.0, High = +1.5, Moderate = +1.0, Low = +0.5. Capped at 1.0.
Final GIRI Score for N-Acetylcysteine. Risk level thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
Full methodology & data sources
The GIRI Score is computed entirely from structured data — no editorial scoring or subjective weighting is applied at any step.
- References: Only approved references are counted. Each reference is assigned an evidence level (L1–L5) and a direction (risk / neutral / benefit) by the reference manager or AI classifier.
- Safety Signals: Sourced from regulatory agencies (FDA, EMA, Health Canada, TGA, and others) and pharmacovigilance databases. Only active signals count toward the score.
- Formula version: GIRI Score v3.7.0 — Q × L × D × S × 10.
- Limitations: The score reflects published evidence and recorded signals as of the last update date. It is not a clinical risk assessment and should not replace advice from a qualified healthcare professional.
Risk Level Classification
Based on available regulatory signals and scientific evidence, this ingredient presents a low safety concern under normal conditions of use.
0–3.0
3.0–5.5
5.5–7.5
7.5–10
The score pin shows exactly where this ingredient falls on the fixed risk scale.
What drove the Low classification for N-Acetylcysteine
A score of 2.5 places this ingredient in the Low band. Thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
0 approved references.
Limited — mostly case reports or animal studies (Level 4–5).
Neutral or mixed — benefit and risk signals roughly balanced.
No active signals — S component is at neutral baseline (0.5), contributing no extra risk weight.
No major regulatory restrictions or advisories recorded across monitored jurisdictions (FDA, EMA, Health Canada, TGA, and others).
How are the Low / Moderate / High / Critical thresholds defined?
The four risk levels are fixed score bands. A score is assigned to exactly one level based on where it falls:
| Level | Score | Meaning |
|---|---|---|
| LOW | 0.0 – 2.9 | Sparse or predominantly beneficial evidence. No active safety alerts. |
| MODERATE | 3.0 – 5.4 | Mixed signals — some risk alongside benefit. Caution at high doses or in sensitive groups. |
| HIGH | 5.5 – 7.4 | Multiple studies or regulatory alerts documenting adverse effects. Professional oversight recommended. |
| CRITICAL | 7.5 – 10 | Regulatory restrictions in one or more major jurisdictions. Serious documented harm. Avoid without specialist supervision. |
Thresholds are fixed constants (GIRI_Score_Utils::LEVEL_THRESHOLDS). They do not change per ingredient and are never subject to editorial adjustment.