Amino acids

NAC

Glutathione · liver

N-acetyl-cysteine; glutathione precursor, antioxidant, mucolytic. Common dose 600–1200 mg.

Daily target

600 mg

Target Range

Upper limit

None

No UL established

Catalog matches

supplements in our catalog

What NAC does

N-acetyl-cysteine is the rate-limiting precursor to glutathione, the body's master antioxidant tripeptide. It's been used clinically for decades — at gram doses to break up mucus in cystic fibrosis and as the standard antidote for acetaminophen overdose. Outside acute medicine, NAC has clinical-trial support for psychiatric uses (trichotillomania, OCD, bipolar depression as adjunct) and PCOS, with weaker evidence for general respiratory and cognitive benefit. The FDA briefly contested NAC's supplement status in 2020 (it's a registered drug for inhalation use); it remains widely sold as a supplement.

Food sources of NAC

Approximate NAC content per serving. Whole-food intake counts toward your daily total alongside any supplemental dose.

Food	Serving	NAC
NAC isn't directly in food	—	—
Cysteine sources: poultry, eggs	3 oz / 1 egg	200–300 mg cysteine
Whey protein	1 scoop	300+ mg cysteine
Allium vegetables (garlic, onions)	1 clove	Sulfur compounds, indirect

Signs of NAC deficiency

●Not an essential nutrient — body synthesizes glutathione from dietary cysteine
●Glutathione depletion (low intake, oxidative load): increased susceptibility to oxidative damage, slower recovery from exposures

Who needs more NAC

Groups and situations where NAC requirements rise or status commonly runs low:

●Acetaminophen overdose (clinical/emergency setting)
●Cystic fibrosis, COPD with thick mucus production
●Adjunct use in trichotillomania, OCD, bipolar depression (psychiatric guidance)
●PCOS (small trials supportive)

How NAC appears on labels

Supplement labels list NAC under several names depending on the chemical form used. Any of these on an ingredients panel counts toward your NAC intake:

nac
n-acetyl-cysteine
n-acetyl cysteine
n-acetylcysteine
acetylcysteine

Best supplements for NAC

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

Nootropics Depot

Cistanche Full Spectrum

Cistanche Ultra Potent Extract Powder

Transparent Labs

Post Workout Supplement

MegaFood Inc.

Magnesium

Complement

Daily Greens by Complement

Thorne

Daily Greens Plus

Deep dive

For mechanism of action, dosing protocols, evidence grade, and interaction warnings on NAC, see the full encyclopedia entry:

N-Acetyl L-Cysteine (NAC) encyclopedia entry →

Research on NAC

Peer-reviewed studies in our research database that reference NAC. Each entry links to a detailed methodology review.

Guides covering NAC

Long-form articles in our guide library that go deeper on NAC — comparisons, protocols, and reviews.

Frequently asked questions

What is the daily target for NAC?

The target range for NAC is 600 mg per day for adults. No Tolerable Upper Intake Level has been established.

What foods are highest in NAC?

NAC isn't directly in food (— per —); Cysteine sources: poultry, eggs (200–300 mg cysteine per 3 oz / 1 egg); Whey protein (300+ mg cysteine per 1 scoop). See the food sources section below for the full list.

What is the best form of NAC to supplement?

N-acetyl-cysteine (NAC) at 600–1,200 mg/day in divided doses. Take on an empty stomach for absorption. Sulfur smell is normal. Don't combine with nitroglycerin without medical supervision.

What are the signs of NAC deficiency?

Not an essential nutrient — body synthesizes glutathione from dietary cysteine; Glutathione depletion (low intake, oxidative load): increased susceptibility to oxidative damage, slower recovery from exposures.

Who is most at risk for low NAC?

Acetaminophen overdose (clinical/emergency setting); Cystic fibrosis, COPD with thick mucus production; Adjunct use in trichotillomania, OCD, bipolar depression (psychiatric guidance).

Related amino acids

Track your full intake

Formulate's free web app aggregates NAC (and ~40 other nutrients) across every supplement in your stack — flagging underdoses, overlaps, and upper-limit overshoots in one view.

Track your intake free →

Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Targets and upper limits are general adult reference values; individual needs vary by age, sex, pregnancy status, and clinical context.