Doctor's Best

Doctor's Best Vitamin C with Q-C, 500 mg, 120 Veggie Caps

Evidence: Limited

Vitamin C, rated Moderate as an ingredient, 500 mg per serving, at or above the lowest studied dose of 500 mg a day. No USP, NSF or Informed Choice verification shown. Moderate requires named third-party verification, so the rating is Limited.

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What studies found on vitamin c

Moderate 2 meta-analyses of randomized trials (13 trials, 556 people in 2011 and 16 trials, 1,013 people in 2021) found a small, consistent drop in serum urate, about 0.35 mg/dL, and a 20-year cohort of 46,994 men linked higher intake to fewer new gout cases, while the 1 trial in people with gout (Stamp 2013, n=40) found a change too small to matter clinically.

Studied dose: 500 mg a day in most trials (2011 meta-analysis median 500 mg). Cohort data cover 500 to 1,500+ mg a day.

  • Juraschek SP 2011, Arthritis Care Res (Hoboken). Meta-analysis of randomized controlled trials, 556 people, Median 30 days. Across 13 trials, vitamin C was associated with serum uric acid 0.35 mg/dL lower than control, with significant heterogeneity.
  • Liu XX 2021, Complement Ther Med. Meta-analysis of randomized controlled trials, 1013 people, Varied by trial. Across 16 trials, vitamin C supplementation was associated with lower serum uric acid, with larger effects in placebo-controlled and shorter trials.
  • Huang HY 2005, Arthritis Rheum. Randomized double-blind placebo-controlled trial, 184 people, 2 months. In nonsmokers without gout, serum uric acid fell 0.5 mg/dL on vitamin C and did not change on placebo.
  • Stamp LK 2013, Arthritis Rheum. Randomized controlled pilot trial, 40 people, 8 weeks. In people with gout, serum urate fell 0.23 mg/dL on vitamin C vs 1.9 mg/dL on allopurinol, which the authors judged clinically insignificant.
  • Choi HK 2009, Arch Intern Med. Prospective cohort (Health Professionals Follow-up Study), 46994 people, 20 years. Men with total vitamin C intake of 1,500 mg a day or more had 45% lower risk of developing gout than men under 250 mg a day (RR 0.55), an observational association.
  • Andrés M 2021, Cochrane Database Syst Rev. Cochrane systematic review of randomized trials, 160 people, Up to 3 months. In adults with chronic gout, the review found only 2 eligible trials and no high-quality evidence supporting or refuting vitamin C.
  • Ferraro PM 2016, Am J Kidney Dis. Prospective cohorts (NHS I, NHS II, HPFS), 197271 people, Median 11.3 to 11.7 years. Men taking 1,000 mg a day or more of supplemental vitamin C had a 19% higher risk of kidney stones (HR 1.19), and women showed no association.

Safety: In 3 US cohorts (Ferraro 2016, 197,271 people), men taking 1,000 mg or more a day of supplemental vitamin C had a 19% higher risk of kidney stones, and no link was seen in women (PMID 26463139). Talk to your doctor before starting a supplement, especially if you take allopurinol, febuxostat or colchicine.

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