Reviewed

Verified by SAC team

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Best for Dose Titration

Double Wood

Double Wood NAC 500 mg per cap / 1000 mg per serving, 210 Capsules Review

Name: Double Wood NAC 500 mg per cap / 1000 mg per serving, 210 Capsules
Brand: Double Wood
Availability: InStock

6.6/10SAC Product Score™

Double Wood's edge is granularity: 500 mg capsules let you dial in 500, 1000, or 2000 mg far more precisely than 600 mg-only bottles, and the brand references specific heavy-metal testing (lead, cadmium, arsenic, mercury) on the listing. The trade-off is olfactory. Buyers routinely complain about a potent sulfur smell — but that odor is a sign of genuine, un-deodorized NAC, not spoilage. There's no absorption enhancement here over any other plain NAC; you're choosing it for dosing flexibility and transparent metals testing, and accepting the smell.

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Read the complete NAC (N-Acetylcysteine) guide →

▸ THE SCORE

How we built the SAC Product Score™ — 6.6/10

Form & Bioavailability25%6.8/10

500 mg plain NAC caps with no absorption enhancement, but the smaller unit enables precise 500/1000/2000 mg titration that 600 mg-only bottles can't match.

Third-Party Testing & Purity25%7/10

99%+ purity third-party tested with specifically referenced heavy-metal results (lead/cadmium/arsenic/mercury) — better metals transparency than most, though not a per-batch NSF seal.

Dose vs Clinical Range20%7/10

1000 mg per 2-cap serving sits comfortably in the 600-1200 mg/day window, and the 500 mg unit makes hitting any target within that range easy.

Tolerability & Safety15%5/10

The strong sulfur smell is the recurring complaint and a real daily-use drawback — it signals authentic un-masked NAC, but it makes the capsules unpleasant. This is the axis that drags the score.

Value15%6.8/10

~$0.24 per 1000 mg serving across 105 servings is solid mid-tier value, competitive on a per-milligram basis.

▸ SPECS

The product at a glance

Form: Plain NAC capsule (un-deodorized), 500 mg each
Dose: 500 mg/capsule; 1000 mg per 2-capsule serving
Count: 210 capsules (105 servings)
Testing: 99%+ purity third-party tested; heavy metals (Pb/Cd/As/Hg) referenced; cGMP USA
Cost per dose: ~$0.24 per 1000 mg serving
Notable: Strong sulfur odor — normal for genuine NAC

▸ TRUTH CHECK

Marketing claims vs. reality

Verified

“Explicitly heavy-metal tested with results referenced”

Double Wood references specific third-party heavy-metal testing (lead, cadmium, arsenic, mercury) on the listing — more metals transparency than most NAC competitors provide.

False

“The strong sulfur smell indicates a spoiled or low-quality product”

The pungent sulfur odor is characteristic of authentic, un-deodorized NAC. It reflects genuine material, not spoilage or poor quality — a common misconception among buyers.

Verified

“500 mg caps offer more precise dosing than 600 mg-only bottles”

The 500 mg unit lets users hit 500/1000/1500/2000 mg targets cleanly, giving finer titration control than fixed 600 mg capsules.

▸ THE DEEP DIVE

What our test actually found

01Titration is the real feature

Most NAC comes only as 600 mg. Double Wood's 500 mg unit makes it easy to build any dose across the clinical range, which is genuinely useful if you're finding your tolerated level.

02The smell is a feature masquerading as a flaw

Reviewers pan the odor, but un-deodorized NAC smells like sulfur precisely because it isn't masked or degraded. It's a usability annoyance, not a quality problem — go in expecting it.

▸ THE TRADE-OFFS

Pros & cons, no sugar-coating

Pros

500 mg caps enable precise dose titration across the clinical range
Published heavy-metal testing (lead, cadmium, arsenic, mercury)
99%+ purity third-party tested, cGMP USA
Solid per-milligram value across 105 servings

Cons

Strong sulfur odor many users find unpleasant to take daily
No absorption enhancement over any other plain NAC
Not a per-batch NSF-certified product

▸ THE BOTTOM LINE

For titrators who can tolerate the smell

Double Wood is the pick if you want to fine-tune your NAC dose and value transparent heavy-metal data. The 500 mg unit is genuinely handy and the metals testing is a real plus. The sulfur smell is the honest cost of authentic, un-masked NAC — if that's a dealbreaker, Sports Research's lemon-zest insert or NOW's veg caps are easier on the nose.

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▸ ALTERNATIVES

If this doesn’t fit — try these

Sports Research Vegan NAC 600 mg

7.6/10

A lemon-zest insert tames the sulfur odor if the smell is your main concern.

See it on the list →

Toniiq NAC 1300 mg

6.2/10

If you want fewer capsules at a higher per-serving dose instead of fine titration.

See it on the list →

▸ RESEARCH