Antioxidant

NAC (N-Acetyl Cysteine)

Also known as: N-Acetyl Cysteine, N-Acetylcysteine, N-Acetyl-L-Cysteine, N-Acetyl Cysteine (NAC) - Detox Focus

Evidence

Precursor to glutathione, the body's master antioxidant. Supports liver, respiratory, and mental health.

Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.

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The highest-scored NAC (N-Acetyl Cysteine) product in our catalog (94/100). Track dose and overlaps in the app.

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Every NAC (N-Acetyl Cysteine) product we have scored

#	Product	Score	Per serving
1	Pure Encapsulations NAC 600 mg	94 A	$0.43
2	Pure Encapsulations NAC 900 mg	94 A	$0.42
3	Life Extension N-Acetyl-L-Cysteine	94 A	$0.20
4	Sports Research NAC Capsules, N-Acetyl-Cysteine, 600 mg	92 A	$0.23
5	NOW Foods NAC	89 A	$0.12
6	Pure Encapsulations NAC + Glycine powder	88 A	$1.27
7	Bluebonnet Nutrition NAC 500 mg	88 A	$0.46
8	Pure Encapsulations PureCell	87 A	$1.28
9	Pure Encapsulations PureDefense with NAC	87 A	$1.90
10	Thorne NAC	86 A-	$0.18
11	Integrative Therapeutics NAC	86 A-	$0.30
12	Country Life NAC, N-Acetyl Cysteine 750 mg	86 A-	$0.51

Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.

Common questions

How much NAC (N-Acetyl Cysteine) should I take?

The typical range is 600-1800 mg daily. Safe long-term

When should I take NAC (N-Acetyl Cysteine)?

Divided doses, away from food. Away from food for glutathione; with food OK for respiratory.

Which form of NAC (N-Acetyl Cysteine) is best?

Capsules — Standard. Other forms in the catalog: Powder, Effervescent, IV, Sustained-release.

Is NAC (N-Acetyl Cysteine) safe?

Commonly reported: GI upset, Sulfur smell/taste. Serious warnings: May reduce efficacy of some chemo. Supports liver detox

Which NAC (N-Acetyl Cysteine) supplement scores highest?

Pure Encapsulations NAC 600 mg, at 94/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.

Daily target & upper limit

600 mg / day

NAC (N-Acetyl Cysteine) has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:

NAC (N-Acetyl Cysteine) dosage reference →

Primary uses

Glutathione support
Liver health
Respiratory health
Mental health
Glutathione production
Liver detox
Mucolytic
Acetaminophen antidote
Ovulation
Insulin sensitivity
Antioxidant
PCOS support

What systematic reviews concluded

Outcomes that systematic reviews of NAC (N-Acetyl Cysteine) reached a verdict on: 5 with a benefit, 3 with no effect, 1 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.

Reviews found a benefit (5)

Benefittraumatic brain injury symptoms(as NAC)

“The strongest evidence emerged for acute mild TBI, where early NAC administration significantly improved symptom resolution, and for PD, where combined intravenous/oral NAC improved dopamine transporter binding.” PMID 41977262

Benefitsperm quality(as NAC)

“Both LC and NAC can improve sperm motility, sperm concentration, and normal morphology, and increase serum testosterone concentration, but have no significant effect on other serum hormones.” PMID 40350672 · 2 reviews

Every supplement reviewed for testosterone & erectile function →

Benefitmuscle soreness(as NAC)

“NAC supplementation significantly diminishes both muscle soreness (p = 0.03; the mean difference (MD) of NAC's effect was -0.43 with a 95% confidence interval (CI), -0.81, -0.04) and lactate concentrations after exercise” PMID 39632267

Every supplement reviewed for exercise recovery →

Benefitlactate concentration(as NAC)

“lactate concentrations after exercise (p = 0.03; the MD -0.56 mmol/L; 95% CI, -1.07, -0.06)” PMID 39632267

Benefitil-6(as NAC)

“A substantial decrease was observed in concentrations of IL-6 (p = 0.03; the standardized MD (SMD) was -1.71; 95% CI, -3.26, -0.16) and TBARS (p = 0.02; SMD was -1.03, 95% CI, -1.90, -0.15).” PMID 39632267

Every supplement reviewed for inflammation →

Reviews found no effect (3)

No effectcontrast-induced nephropathy(as NAC)

“Neither oral nor IV NAC decreases the risk of contrast-induced nephropathy.” PMID 42015439

No effecttnf-alpha and creatine kinase(as NAC)

“However, we saw no significant effect of NAC on TNF-α, CK or GSSG concentrations.” PMID 39632267

Every supplement reviewed for inflammation →

No effectpsa levels(as N-Acetyl-L-Cysteine)

“Five RCTs reported no significant effects compared with placebo.” PMID 23567264

Not enough to say: female infertility.

5 findings from reviews in specific patient groups (such as cancer, pregnancy or surgery) are not shown here.

How it works

Rate-limiting precursor to glutathione
Mucolytic (thins mucus)
Modulates glutamate
Acetaminophen antidote

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
Duration: Safe long-term
Special populations: Liver support, respiratory, OCD/addiction

Forms

Capsules
Powder
Effervescent
IV
Sustained-release

Safety

Common side effects

GI upset
Sulfur smell/taste

Contraindications

Caution active cancer treatment

Products containing NAC (N-Acetyl Cysteine)

Top-scoring supplements in our catalog that list NAC (N-Acetyl Cysteine) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Pure Encapsulations

Pure Encapsulations

Life Extension

Sports Research

NAC Capsules, N-Acetyl-Cysteine, 600 mg

Find on Amazon

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Evidence notes

Well-studied glutathione precursor

Grade A: Multiple well-designed human trials support the main claims.

Cited research for NAC (N-Acetyl Cysteine)

Clinical studies referenced across Formulate guides that mention nac (n-acetyl cysteine). Each links to the full study page with PubMed source + the guides that cite it.

NAC (N-Acetyl Cysteine) compared head-to-head

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.