NAC (N-Acetyl Cysteine)
Antioxidant3 forms compared ↓
Also known as: N-Acetyl Cysteine, N-Acetylcysteine, N-Acetyl-L-Cysteine, N-Acetyl Cysteine (NAC) - Detox Focus
A
Grade A💊 600-1800 mg daily🎯 12 primary uses🔗 3 synergies⚠️ Review warnings
Levels upHeart & Longevity+50 pts
Overview
Precursor to glutathione, the body's master antioxidant. Supports liver, respiratory, and mental health.
Primary Uses
Glutathione supportLiver healthRespiratory healthMental healthGlutathione productionLiver detoxMucolyticAcetaminophen antidoteOvulationInsulin sensitivityAntioxidantPCOS support
Frequently Asked About NAC (N-Acetyl Cysteine)
How much NAC (N-Acetyl Cysteine) should I take?
The typical effective range is 1,200-1,800 mg + glycine. Individual needs vary based on age, body weight, diet, and goals — start at the lower end and adjust based on response. Always consult a healthcare provider before starting a new supplement.
When is the best time to take NAC (N-Acetyl Cysteine)?
Divided doses, away from food. Consistency matters more than perfect timing — pick a daily anchor (e.g. with breakfast or before bed) and stick with it.
Should I take NAC (N-Acetyl Cysteine) with food?
Away from food for glutathione; with food OK for respiratory.
What is the best form of NAC (N-Acetyl Cysteine)?
Liposomal NAC is generally the best-absorbed form (Phospholipid-encapsulated NAC for higher absorption). Cheaper forms exist but often deliver less usable NAC (N-Acetyl Cysteine) per dose.
Does NAC (N-Acetyl Cysteine) interact with medications?
Yes — known interactions include Nitroglycerin - enhances and Some chemo - consult oncologist. If you take any prescription medication, talk to your doctor or pharmacist before starting NAC (N-Acetyl Cysteine).
What does NAC (N-Acetyl Cysteine) pair well with?
NAC (N-Acetyl Cysteine) stacks well with Vitamin C, Selenium, and Glycine — these combinations either improve absorption or work synergistically toward common goals.
Who should not take NAC (N-Acetyl Cysteine)?
NAC (N-Acetyl Cysteine) should be avoided or used with caution by people with Caution active cancer treatment. Pregnant or breastfeeding women should consult a healthcare provider before use.
Compare Forms
3 formsDifferent chemical forms vary in absorption, side effects, and best use cases. Higher bioavailability scores indicate better absorption.
Standard N-Acetyl Cysteine (NAC)
HIGH 90Acetylated cysteine — the standard, well-studied form
Best for:Glutathione precursorLiver supportMucolytic (thinning mucus)OCD/PANDAS adjunct
💡 Good. ~6-10% oral bioavailability but reliably raises plasma cysteine.
✅ Pros
- • Most clinical data
- • Affordable
- • Well-tolerated
⚠️ Cons
- • Strong sulfur smell
- • Empty stomach for best absorption
- • FDA gray area as supplement (US)
📝 Standard 600-1200 mg/day. Pair with glycine (GlyNAC) for greater GSH boost.
Liposomal NAC
HIGH 95Phospholipid-encapsulated NAC for higher absorption
Best for:Lower effective dosesSensitive stomachs
💡 Higher than standard NAC; bypasses degradation.
✅ Pros
- • Better absorption
- • Less odor
⚠️ Cons
- • Expensive
- • Limited research vs standard NAC
📝 Marginal benefit vs standard NAC; standard form has the trial data.
Sustained-Release NAC
HIGH 85Time-release formulation to maintain plasma cysteine
Best for:Steady glutathione synthesisTwice-daily compliance
💡 Spread over hours rather than peak/trough.
✅ Pros
- • Stable levels
- • Good compliance
⚠️ Cons
- • More expensive
- • Less peak effect
📝 Niche; standard NAC twice daily achieves similar end result for less.
Dosage
Typical range
600-1800 mg daily
Timing
Divided doses, away from food
With food
Away from food for glutathione; with food OK for respiratory
Dose Tiers
Moderate
600-1,200 mg/day
Optimal
1,200-1,800 mg + glycine
Therapeutic
2,400-3,600 mg/day
Upper Limit
No established UL
Duration
Safe long-term
Special Populations
Liver support, respiratory, OCD/addiction
Research & Studies
Landmark clinical studies on NAC (N-Acetyl Cysteine). Each title links to a plain-English breakdown — what the study shows, what its limitations are, and how to read around them.
- N-acetylcysteine in psychiatry: current therapeutic evidence and potential mechanisms of action
Reviews evidence for NAC as an adjunctive psychiatric treatment, with strongest data in trichotillomania, OCD, addictive behaviors, and as a glutathione precursor for oxidative stress reduction.
- Effectiveness of N-acetylcysteine in the prevention of contrast-induced nephropathy: a systematic review and meta-analysisKelly AM, Dwamena B, Cronin P, et al. · 2008 · Annals of Internal MedicineMeta-analysis
Meta-analysis of 41 trials found NAC associated with reduced risk of contrast-induced nephropathy, supporting clinical use of NAC for renal protection in high-risk patients undergoing contrast imaging.
Browse all curated studies →
Mechanism of Action
- • Rate-limiting precursor to glutathione
- • Mucolytic (thins mucus)
- • Modulates glutamate
- • Acetaminophen antidote
Evidence Quality
Evidence Grade A
Well-studied glutathione precursor
Safety & Contraindications
Serious Warnings
- • May reduce efficacy of some chemo
Contraindications
- • Caution active cancer treatment
Common Side Effects
- • GI upset
- • Sulfur smell/taste
Pregnancy & Breastfeeding
Consult healthcare provider
Liver & Kidney Notes
Supports liver detox
Interactions
💊 Medications
- • Nitroglycerin - enhances
- • Some chemo - consult oncologist
🧪 Supplements
- • Works with vitamin C, selenium
🍽️ Food & Alcohol
- • Helps alcohol-induced liver damage
Stacking & Synergies
Pairs Well With
Avoid Combining With
Best Goal Synergies
LiverRespiratoryGlutathione
Buying Guide
What to Look For
- • Pure NAC
Standardization Markers
NAC content
Adulteration risk
Low
Practical Notes
- • Take away from food for best absorption
- • Acetaminophen overdose antidote
- • Cheapest way to raise glutathione
- • Take with vitamin C for best effect
- • May cause histamine issues in some
- • Synergistic with inositol for PCOS
- • May thin cervical mucus (consider timing)
- • Antioxidant support
Tags
antioxidantglutathioneliverrespiratoryamino-aciddetoxpcosovulationinsulin
Top Products with NAC (N-Acetyl Cysteine)
Highest-scored catalog products containing NAC (N-Acetyl Cysteine), ranked by our scoring engine.
Browse all NAC (N-Acetyl Cysteine) products →
Related Guides
In-depth guides covering NAC (N-Acetyl Cysteine) — protocols, comparisons, and use cases.
More in Antioxidant
Other ingredients in the Antioxidant category.
Alpha-Lipoic Acid (ALA)
Universal antioxidant working in both water and fat. Regenerates other antioxidants and supports blood sugar metabolism.
Astaxanthin
Astaxanthin is a carotenoid with potent antioxidant and anti-inflammatory properties, naturally present in krill and microalgae. It crosses the blood–brain barrier and may support eye, skin, and cellular health.
Broccoli
Broccoli powder is a whole-food derived ingredient rich in sulforaphane, glucosinolates, and polyphenols that support antioxidant and detoxification pathways. Evidence supports potential benefits for cellular health and inflammatory response, though most human research uses fresh broccoli or concentrated extracts rather than powder forms.
C60 (Carbon 60 Fullerene)
Spherical carbon molecule with potent antioxidant properties in olive oil. Controversial with limited human data despite promising rodent longevity studies.
Citrus Bioflavonoids
Plant compounds from citrus fruits that enhance vitamin C absorption and provide antioxidant, anti-inflammatory, and vascular support benefits.
CoQ10 (Ubiquinone/Ubiquinol)
Ubiquinol is the reduced, active form of CoQ10 that plays a critical role in cellular energy production via the mitochondrial electron transport chain and serves as a lipid-soluble antioxidant. It is more bioavailable than standard ubiquinone (oxidized CoQ10), particularly in aging populations.
Last reviewed: September 2026 by the Formulate Research Team. Sources cited above; methodology and scoring criteria published here.
Cite this page
Formulate Research Team. (2026, September). NAC (N-Acetyl Cysteine) — Evidence-Based Supplement Guide. Formulate Supplement Encyclopedia. https://app.formulate-health.app/learning/supplements/nac
Educational content based on published research and our scoring methodology. Not medical advice — consult a qualified healthcare provider before starting, stopping, or changing supplements, especially if you take medications, are pregnant, or have a medical condition.