NOW NAC 600 mg with Selenium & Molybdenum, 250 Veg Capsules Review
#2 of 10 · Best Value✓ Label verified · Supplement Facts read Sep 7, 2026Real retailer photo, cut out. Label unedited.
Buy it. The one to buy if you're not sure which NAC to buy. Clinical 600 mg dose, credible in-house testing, and the lowest realistic cost per dose among trustworthy brands.
$24.99~$0.10 per 600 mg capsule
Why It Scores 8.0 — And The Label Line Behind Each Number
Form & Bioavailability
25% of scorePlain 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.
- Form
- Plain NAC veg capsule + selenium & molybdenum cofactors
Third-Party Testing & Purity
25% of scoreNOW'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.
- Testing
- NOW in-house UL-audited GMP lab; non-GMO, vegan, soy/gluten/dairy-free
Dose vs Clinical Range
20% of score600 mg/capsule fits the 600-1200 mg/day studied window. One or two daily reaches the range cleanly.
- Dose
- 600 mg NAC per capsule
Tolerability & Safety
15% of scoreStandard 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.
Value
15% of score~$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.
- Count
- 250 veg capsules (8+ month supply at 1/day)
- Cost per dose
- ~$0.10 per 600 mg capsule
- More Specs
- Added cofactors
- 25 mcg selenium + 25 mcg molybdenum
Label verified. Every figure read from the Supplement Facts photo, Sep 7, 2026.
Marketing Claims Vs. Reality
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.
What Our Test Actually Found
The selenium is a footnote, not a feature
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.
Value plus credible testing is a rare combo
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.
Full analysis: all pros & cons (7), buy if / skip if
- ~$0.10/capsule and an 8+ month supply — the best cost per dose from a trustworthy brand
- NOW's in-house UL-audited lab is unusually transparent
- Clinical 600 mg dose, vegan and free of common allergens
- Huge 250-count bottle minimizes reorders
- Bundled selenium/molybdenum is trivial and can quietly add to cumulative selenium intake
- Plain capsule with no absorption enhancement
- Not a per-batch NSF Certified for Sport product
- ~$0.10/capsule and an 8+ month supply — the best cost per dose from a trustworthy brand
- NOW's in-house UL-audited lab is unusually transparent
- Clinical 600 mg dose, vegan and free of common allergens
- Bundled selenium/molybdenum is trivial and can quietly add to cumulative selenium intake
- Plain capsule with no absorption enhancement
- Not a per-batch NSF Certified for Sport product
Clinical 600 mg dose, credible in-house testing, and the lowest realistic cost per dose among trustworthy brands. The bundled selenium/molybdenum is marketing more than medicine, but it's harmless. For the overwhelming majority of buyers, this is the right call.
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.
The right default for almost everyone
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.
If This Doesn’t Fit — Try These
01Pure Encapsulations NAC 600 mg
If you want the least-adulterated, best-verified NAC and will pay for that peace of mind, this is the one.
05Nutricost NAC 600 mg
If price is your only tie-breaker, this and NOW are the two to compare.
Quick Answers
Does the added selenium make this better than plain NAC?
No. At 25 mcg it's a token amount with no demonstrated benefit on top of 600 mg NAC. Treat it as neutral — and remember it counts toward your total daily selenium from food and other supplements.
Is NOW's testing trustworthy without an NSF seal?
Yes, within limits. NOW runs a UL-audited in-house lab and publishes unusually detailed testing data. That's not the same as per-batch NSF Certified for Sport, but it's more transparency than most brands offer.
Sources & Further Reading
2 peer-reviewed sources, each linked to PubMed
- [1] Smilkstein MJ, et al. N Engl J Med. 1988;319(24):1557-1562. PMID 3059186 — Efficacy of oral N-acetylcysteine in the treatment of acetaminophen overdose. Landmark trial establishing oral NAC's proven clinical role in acetaminophen toxicity, the strongest evidence base for the molecule.
- [2] Decramer M, et al. Lancet. 2005;365(9470):1552-1560. PMID 15866309 — Effects of N-acetylcysteine on outcomes in chronic obstructive pulmonary disease (BRONCUS). 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.
Affiliate disclosure: every Amazon link uses our Associates tag (superachieverclub-20). We earn a small commission at no cost to you; it funds independent reviews. We never accept payment to change a ranking.