Does Vitamin C Lower Uric Acid? What the Trials Actually Show

TL;DR

• Vitamin C supplements lower uric acid a little: a 2011 meta-analysis of 13 trials found an average drop of 0.35 mg/dL, mostly at 500 mg a day.
• In people who already have gout the effect was even smaller, and the ACR’s 2020 guideline conditionally recommends against adding vitamin C as a gout treatment.
• Food sources are worth eating; high-dose pills (around 1,000 mg or more a day) are linked to kidney stones in men.

Yes, vitamin C lowers uric acid, but only slightly. Across randomized trials the average drop is about a third of a milligram per deciliter, and in people who already have gout the effect has been too small to matter clinically.

That gap between “it lowers a blood test number” and “it helps gout” is why vitamin C advice looks contradictory online. Some sources recommend 500 mg a day, while the American College of Rheumatology (ACR) conditionally recommends against it as a gout treatment. Here is what the studies actually found, and how to use vitamin C sensibly.

What Do the Studies Show?

The evidence comes in three kinds: short trials measuring uric acid, long studies tracking who develops gout, and small trials in people who already have it.

Study	Who	Dose and length	Result
Huang et al., Arthritis & Rheumatism 2005	184 nonsmokers without gout	500 mg/day, 2 months	Uric acid fell 0.5 mg/dL vs. no change on placebo
Juraschek et al., meta-analysis, 2011	13 trials, 556 people	Median 500 mg/day, median 30 days	Average drop of 0.35 mg/dL
Stamp et al., Arthritis & Rheumatism 2013	40 people with gout	500 mg/day, 8 weeks	Drop of ~0.23 mg/dL vs. ~1.9 mg/dL with allopurinol
Choi et al., Archives of Internal Medicine 2009	46,994 men followed 20 years	Usual diet and supplements	1,500 mg/day or more linked to 45% lower gout risk vs. under 250 mg
Physicians’ Health Study II, 2022 follow-up analysis	14,641 male physicians	500 mg/day vs. placebo, up to 10 years	12% fewer new gout diagnoses

The pattern is consistent: vitamin C nudges uric acid down, and people who get more of it are somewhat less likely to develop gout. The 2011 meta-analysis also found a lot of variation between trials, with larger drops in placebo-controlled studies. A later meta-analysis of 16 trials in 2021 reached the same overall conclusion.

The gout trials are the sobering part. In Stamp’s study, the larger of the two the ACR relied on, participants started with urate around 8.4 mg/dL. The ACR’s treat-to-target goal is below 6 mg/dL. A 0.23 mg/dL drop barely moves the needle, while allopurinol moved it about eight times as far. (For context on those numbers, see our uric acid levels chart.)

Why Does the ACR Guideline Advise Against Vitamin C?

The ACR’s 2020 guideline says adding vitamin C supplementation is “conditionally recommended against” for patients with gout, regardless of disease activity. The panel’s reasoning was simple: two small randomized trials in people with gout (29 and 40 participants) showed clinically insignificant changes in urate, so the data weren’t strong enough to keep recommending it.

“Conditional” matters here. It means the panel judged that most patients shouldn’t rely on vitamin C for gout, not that vitamin C is harmful. It also doesn’t apply to vitamin C from food. The Arthritis Foundation, by contrast, still suggests about 500 mg a day. The two positions aren’t as far apart as they sound: both accept that vitamin C can lower urate somewhat, and they differ on whether the effect is big enough to recommend for people with gout.

The more important point is what vitamin C can’t do. It won’t stop a flare that has already started, and it can’t replace urate-lowering medication for people who need it. If you’re on allopurinol, see allopurinol and diet for the food changes that do add up.

How Does Vitamin C Affect Uric Acid?

The leading explanation is that vitamin C acts at the kidneys, helping them clear more uric acid into the urine. In the 2005 trial, vitamin C also slightly improved estimated kidney filtration compared with placebo.

The mechanism isn’t settled, though. A 2026 crossover trial in 40 adults with high uric acid found that 600 mg a day for two weeks lowered serum uric acid without any measurable change in urinary uric acid excretion. Whatever the pathway, the size of the effect is what matters for you, and that has been modest in every trial.

How Much Vitamin C Do You Need?

Group	Recommended daily intake	Upper limit
Adult men	90 mg	2,000 mg
Adult women	75 mg	2,000 mg
People who smoke	Add 35 mg	2,000 mg

Most gout trials used 500 mg a day, well above the recommended intake but below the 2,000 mg upper limit. Above that limit, stomach upset and diarrhea become more likely, and kidney stones are a rare risk.

What Are the Best Food Sources of Vitamin C?

You can reach several hundred milligrams a day from food without trying hard. Values below are from USDA FoodData Central.

Food	Serving	Vitamin C
Red bell pepper, raw	1 cup chopped	190 mg
Green bell pepper, raw	1 cup chopped	120 mg
Orange juice	1 cup	124 mg
Strawberries	1 cup halves	89 mg
Pineapple	1 cup chunks	79 mg
Orange	1 medium	70 mg
Kiwifruit	1 medium	64 mg
Cantaloupe	1 cup cubes	59 mg
Broccoli, boiled	½ cup	51 mg
Brussels sprouts, boiled	½ cup	48 mg

A cup of red pepper, a cup of strawberries, an orange, a kiwi and half a cup of broccoli add up to about 460 mg, close to the trial dose.

Favor vegetables and whole fruit over juice. Orange juice is rich in vitamin C, but it also delivers a concentrated dose of fructose, which raises uric acid. See is orange juice bad for gout for the trade-off. Peppers and broccoli give you the vitamin C with far less sugar than juice.

Can Vitamin C Supplements Cause Kidney Stones?

This is the main reason to be careful with high doses, and it’s especially relevant because people with gout already have a higher rate of kidney stones than people without it.

• A Swedish study of 23,355 men, published in JAMA Internal Medicine in 2013, found that men taking vitamin C supplements (typically around 1,000 mg per tablet) had about twice the risk of kidney stones over 11 years. Daily users had the highest risk.
• A 2016 analysis of more than 190,000 US adults found that supplemental vitamin C of 1,000 mg a day or more was linked to a modestly higher stone risk in men, but not in women. Vitamin C from food was not linked to stones.

If you’ve had kidney stones, particularly uric acid or calcium oxalate stones, ask your doctor before taking any vitamin C supplement.

A Sensible Approach to Vitamin C and Gout

• Eat it first. Build meals around peppers, broccoli, berries, citrus and kiwi. They bring fiber and potassium along with the vitamin C.
• Don’t count on a pill to reach your urate target. If your uric acid is above 6 mg/dL, talk to your doctor about treatment rather than stacking supplements.
• If you do supplement, keep it moderate. Trials used 500 mg a day; there’s no evidence that more helps gout, and doses around 1,000 mg or more are where the clearest kidney-stone signal appears in men.
• Check interactions. Tell your doctor or pharmacist about any supplement you take alongside gout or other medicines.
• Measure, don’t guess. If you try vitamin C, a repeat urate test after a couple of months will tell you whether it did anything for you.

Vitamin C is one of several small dietary levers, alongside dairy and cherries. For the full list, see foods that lower uric acid.

The Bottom Line

Vitamin C does lower uric acid, but modestly: about 0.35 mg/dL on average in trials, and less than that in trials of people with gout. People who get more vitamin C are somewhat less likely to develop gout in the first place, but for people who already have it, the ACR’s 2020 guideline conditionally recommends against adding supplements as a treatment. Eat plenty of vitamin C-rich vegetables and fruit, be cautious with supplements of 1,000 mg or more, especially if you’ve had kidney stones, and rely on proven urate-lowering treatment when you need it.

Sources

• FitzGerald JD et al. 2020 American College of Rheumatology Guideline for the Management of Gout
• Juraschek SP et al. Effect of oral vitamin C supplementation on serum uric acid: a meta-analysis of randomized controlled trials (Arthritis Care & Research 2011)
• Stamp LK et al. Clinically insignificant effect of supplemental vitamin C on serum urate in patients with gout (Arthritis & Rheumatism 2013)
• Thomas LD et al. Ascorbic acid supplements and kidney stone incidence among men: a prospective study (JAMA Internal Medicine 2013)
• MedlinePlus: Vitamin C

This article is for informational purposes only and is not medical advice. Talk to your rheumatologist or healthcare provider about your specific situation.