The one to buy if you're not sure which NAC to buy
If Pure Encapsulations is the connoisseur's pick, NOW NAC is the sensible one almost everyone should actually buy. You get 250 capsules of 600 mg NAC for around $25 — roughly $0.10 a dose and an 8-plus-month supply — backed by NOW's in-house, UL-audited testing lab, which is genuinely one of the most transparent quality operations in supplements. The added selenium and molybdenum are pitched as sulfur-metabolism cofactors, and while the amounts are trivial, they don't hurt. This is the editor's default: clinical dose, credible testing, unbeatable cost per capsule.
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Read the complete NAC (N-Acetylcysteine) guide →Plain 600 mg NAC veg capsule with no absorption enhancement. The 25 mcg selenium + 25 mcg molybdenum are token cofactors, not a bioavailability upgrade — but the base NAC is well-absorbed standard material.
NOW's in-house UL-audited lab is among the most transparent in the category, publishing extensive testing data. Not a per-product NSF Certified for Sport seal, but more visibility than most.
600 mg/capsule fits the 600-1200 mg/day studied window. One or two daily reaches the range cleanly.
Standard NAC tolerability; typical sulfur note. The 25 mcg selenium is trivial but worth remembering if you also take a multivitamin and eat Brazil nuts — selenium is cumulative.
~$0.10/capsule and 250 caps per bottle make this the standout cost-per-dose winner among trustworthy brands — an 8+ month supply at one per day.
“Selenium and molybdenum meaningfully boost NAC's sulfur metabolism”
At 25 mcg each these are token amounts included as marketing cofactors; there's no clinical evidence that adding trace selenium/molybdenum to 600 mg NAC changes glutathione or liver outcomes.
“One of the most transparent testing labs in the supplement category”
NOW operates a widely respected in-house, UL-audited analytical lab and publicly shares testing methodology and results, exceeding the transparency of most competitors here.
“Best cost per dose among trustworthy NAC brands”
At ~$0.10/capsule for a 250-count bottle from a credibly tested brand, no other pick on this list matches the cost per clinical dose.
Don't buy this for the cofactors — 25 mcg selenium is a fraction of a day's intake and clinically inert here. Do note that selenium stacks across your multivitamin and diet, so it's a reason to track, not to celebrate.
Cheap NAC is easy; cheap NAC from a lab that actually publishes its testing is not. NOW is the unusual case where the value pick is also a quality pick.
NOW NAC is what we'd hand a friend who asked 'which NAC should I get?' Clinical dose, credible testing, and a cost per dose nothing else on this list beats. Ignore the selenium marketing, remember it counts toward your daily selenium, and you have the best all-round value pick here.
Step up to hypoallergenic practitioner-grade sourcing if excipient purity matters more than price.
See it on the list →Even cheaper per bottle if you want a bare single-ingredient formula and don't need NOW's lab transparency.
See it on the list →Landmark trial establishing oral NAC's proven clinical role in acetaminophen toxicity, the strongest evidence base for the molecule.
Large RCT showing oral NAC did not reduce COPD decline overall — a key example of oral NAC's mixed real-world efficacy versus its reputation.
