Garden of Life

Dr. Formulated Quercetin Drop Uric Acid 500 mg

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.

We earn a commission when you buy through paid links on this page, at no extra cost to you. It never changes a rating or a ranking. As an Amazon Associate I earn from qualifying purchases. How we stay independent.

Check price at Amazon Brand label we read

On the label

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.

What studies found on quercetin

Limited 1 small placebo-controlled crossover trial (Shi 2016, n=22 healthy men) found a drop in plasma uric acid, and the other human data are non-randomized real-life cohorts reported by authors with industry ties, with no trial in people with gout.

Studied dose: 400 to 500 mg quercetin a day (400 mg as Quercetin Phytosome).

  • Shi Y 2016, Br J Nutr. Randomized double-blind placebo-controlled crossover trial, 22 people, 4 weeks per arm. In healthy men with high-normal uric acid, plasma uric acid was 26.5 µmol/L (about 0.45 mg/dL) lower after 4 weeks of quercetin than after placebo.
  • Di Pierro F 2025, Front Nutr. 3 real-life cohort studies, not randomized, 250 people, Up to 90 days. Serum uric acid fell 13% to 15% from baseline in quercetin groups, in non-randomized cohorts whose authors include consultants to Pharmextracta, an Italian supplement company.

Safety: No adverse effects on glucose or blood pressure were reported in the 2016 trial (n=22). This review found no study of quercetin taken with allopurinol, febuxostat or colchicine. Talk to your doctor before starting a supplement, especially if you take allopurinol, febuxostat or colchicine.

What studies found on tart cherry (juice, concentrate, extract)

Limited The largest placebo-controlled trial in people with gout (Stamp 2020, n=50) found no change in serum urate over 28 days at any dose, a 2026 meta-analysis of 4 trials (392 people) found a small pooled drop with high heterogeneity, and the flare data come from 1 observational case-crossover study (Zhang 2012, n=633).

Studied dose: Concentrate 15 to 60 mL a day (7.5 to 30 mL twice daily), juice 240 to 480 mL a day, extract or powder capsules 480 to 3,600 mg a day.

  • Stamp LK 2020, Rheumatology (Oxford). Randomized placebo-controlled dose-finding trial, 50 people, 28 days. In people with gout, half of them on allopurinol, no dose of tart cherry concentrate changed serum urate, urine urate or flare frequency compared with placebo.
  • Zhang Z 2026, Asia Pac J Clin Nutr. Meta-analysis of randomized controlled trials, 392 people, Varied by trial. Pooled across 4 trials, tart cherry intake was associated with a small reduction in serum uric acid (standardized mean difference -0.22, 95% CI -0.43 to -0.01) with substantial heterogeneity, and the authors called the evidence limited.
  • Zhang Y 2012, Arthritis Rheum. Case-crossover study (online cohort of people with gout), 633 people, 1 year of follow-up. Cherry intake in the prior 2 days was associated with 35% lower odds of a gout flare (OR 0.65) and cherry extract with 45% lower odds (OR 0.55), an observational association that does not show cause and effect.
  • Singh JA 2020, J Clin Rheumatol. Randomized pilot feasibility trial, active comparator, no placebo, 84 people, 9 months. Compared with baseline, flares per month went from 0.36 to 0.22 on cherry extract and from 0.31 to 0.28 on diet change, in a feasibility trial with no placebo arm.
  • Wang C 2023, Arthritis Res Ther. Randomized open-label controlled trial, 282 people, 12 weeks. In men with gout starting febuxostat, serum urate fell by a similar amount in all 3 groups, so the tart cherry mixture showed no extra urate change, while CRP and urine albumin were lower in the cherry group at week 12.
  • Jäger R 2026, J Diet Suppl. Randomized double-blind placebo-controlled crossover trial, 10 people, 4 weeks per arm. In 10 healthy adults, plasma urate was 37.4% lower after 4 weeks of 500 mg extract than after placebo, a single very small trial whose authors include staff of Increnovo LLC and Specnova LLC, supplement consulting and ingredient firms.
  • Hillman AR 2021, Plant Foods Hum Nutr. Randomized placebo-controlled trial (6 arms), 48 people, 48 hours. Serum uric acid dropped for 2 to 24 hours after a dose, averaging 8%, and the drop was not maintained with continued intake.
  • Gonzalez DE 2024, Nutrients. Randomized double-blind placebo-controlled crossover trial, 25 people, Acute dose plus 1 week. In adults with mildly high uric acid, tart cherry powder did not change the rise in uric acid after a high-purine meal, acutely or after 1 week.
  • Lamb KL 2026, Nutr Health. Randomized open-label crossover trial with water control, 12 people, 24 hours. Tart cherry juice did not change serum or urine uric acid compared with water, and uric acid moved through the day after either drink.

Safety: Juices and concentrates carry fruit sugar, and Stamp 2020 recorded 1 case of high blood sugar possibly linked to concentrate (PMID 31891407). A 2019 case report describes acute kidney injury in a man with chronic kidney disease who took black cherry concentrate for a gout flare (PMID 30963415). Talk to your doctor before starting a supplement, especially if you take allopurinol, febuxostat or colchicine.

Other products with the same ingredient