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ImmuneNeuroprotectiveMitochondrial

N-Acetyl Cysteine (NAC)

Antioxidant supplement that research suggests may support glutathione production and respiratory health.

Human Trials

45

3,200 participants

Risk Level

Low Risk

Monthly Cost

$15$40 /month

Higher quality forms like sustained-release may cost more

Quick Facts

Category
Supplement
Research Field
Supplements
Evidence Grade
B – Moderate
Risk Level
Low
Monthly Cost
$15 – $40
Human Trials
45

Typical Dose

600–1200 mg/day

Range

600–1800 mg/day in divided doses

Timingwith food
Formcapsule or effervescent tablet
NotesPrecursor to glutathione – the body's primary antioxidant. Stack with glycine for GlyNAC protocol (equal gram doses). May blunt some hormetic adaptations to exercise if taken immediately post-workout.

For informational purposes only – not medical advice. See disclaimer

Research Velocity

+9%
180 publications in the last 12 months · steady increase in publications
Moderate Community Interest
60 mentions
Sources:LongecityReddit
Updated 2026-03-16

Mechanism of Action

N-Acetyl Cysteine serves as a precursor to glutathione, the body's primary intracellular antioxidant. Research indicates it works by providing cysteine, a rate-limiting amino acid for glutathione synthesis. Studies suggest NAC may also have mucolytic properties, helping to break down mucus, and direct antioxidant effects through its sulfhydryl group. Additionally, research indicates it may modulate inflammatory pathways and support mitochondrial function.

Overview

N-Acetyl Cysteine (NAC) is a modified form of the amino acid cysteine that research suggests serves as a powerful precursor to glutathione, often called the body's 'master antioxidant.' Studies indicate that NAC supplementation may help replenish glutathione levels, particularly under conditions of oxidative stress or depletion. Originally developed as a mucolytic agent for respiratory conditions, research has expanded to explore its potential benefits for liver health, immune function, and even mental health conditions.

Clinical trials suggest NAC may be particularly beneficial for respiratory health, with studies showing improvements in chronic obstructive pulmonary disease (COPD) symptoms and reduced exacerbation frequency. Research also indicates potential benefits for liver protection, particularly in cases of acetaminophen toxicity, where it's used as a standard medical treatment. Some studies suggest NAC may support cardiovascular health, immune function, and even mental health conditions like trichotillomania and substance use disorders, though more research is needed in these areas.

While generally well-tolerated, NAC can cause gastrointestinal upset in some individuals, and high doses may lead to nausea or vomiting. The supplement has faced regulatory challenges in some jurisdictions due to its classification as both a supplement and pharmaceutical agent. Quality varies significantly between manufacturers, making third-party testing important for consumers seeking reliable products.

Known Interactions

  • May enhance effects of nitroglycerin and increase hypotension risk
  • Can reduce absorption of some antibiotics if taken simultaneously
  • May interfere with certain laboratory tests due to its reducing properties
  • Potential interactions with blood thinning medications due to antiplatelet effects

Legal Status by Country

📍

Your country (United States)

FDA removed NAC supplements in 2022, but enforcement varies by retailer

Varies
✈️

Available without prescription in:

Australia, Brazil, Canada, China, Colombia, Germany, India, Israel, Japan, Mexico, Netherlands, Russia, South Korea, Switzerland, Thailand, Turkey, UAE, United Kingdom, Panama

Australia
OTC
✈️Brazil
OTC
Canada
OTC
China
OTC
✈️Colombia
OTC
Germany
OTC
✈️India
OTC
✈️Israel
OTC
Japan
OTC
✈️Mexico
OTC
Netherlands
OTC
Russia
OTC
✈️South Korea
OTC
Switzerland
OTC
✈️Thailand
OTC
✈️Turkey
OTC
✈️UAE
OTC
United Kingdom
OTC
✈️Panama
Unregulated
📍United States
Varies

📍 = your selected country · ✈️ = medical tourism destination · Always verify current local regulations before travel.

Key Research

Last verified: 2026-03-16