Uric acid is the final waste product your body creates when it breaks down purines, a type of compound found in your cells and in many foods. Your liver produces most of it, and your kidneys filter the majority out through urine. In healthy amounts, uric acid actually serves useful purposes. But when levels climb too high, it can crystallize in joints and tissues, causing gout, kidney stones, and contributing to cardiovascular problems.
How Your Body Makes Uric Acid
Purines are molecules that form part of your DNA and RNA, and they’re constantly being recycled as old cells die and new ones replace them. Your body also gets purines from food. When purines are broken down, they pass through a two-step conversion: first into a substance called hypoxanthine, then into xanthine, and finally into uric acid. A single enzyme drives both of those last two steps, acting as the bottleneck that controls how much uric acid you produce at any given time.
About two-thirds of the uric acid in your blood comes from your body’s own internal cell turnover. The remaining third comes from the purines in your diet. This is why diet changes alone often aren’t enough to bring very high levels back to normal, though they can reduce the frequency and severity of flare-ups in conditions like gout.
Several things can ramp up purine breakdown beyond normal levels. Fructose and alcohol both deplete your cells’ energy stores in ways that accelerate uric acid production. Rapid cell turnover from illness, intense exercise, or certain medical treatments also floods the system with purines that get converted into uric acid.
Why Humans Have Higher Levels Than Most Animals
Most mammals produce an enzyme called uricase that breaks uric acid down further into a more easily excreted substance. Humans lost this enzyme millions of years ago through a series of genetic mutations shared with other primates. This wasn’t necessarily a mistake. Without uricase, uric acid levels in primate blood rose, and this likely provided survival advantages during periods of climate change and food scarcity.
Uric acid is a powerful antioxidant. When early primates also lost the ability to make their own vitamin C (another antioxidant), uric acid stepped in as the body’s primary free radical scavenger. Higher uric acid levels also amplified the effects of fructose on fat storage, helping primates build energy reserves during times when fruit was available so they could survive lean periods. In a world of abundant food, though, this same mechanism works against us.
Normal Blood Levels
Uric acid is measured through a simple blood test. Standard reference ranges differ by sex and age:
- Adult males: 4.0 to 8.5 mg/dL
- Adult females: 2.7 to 7.3 mg/dL
- Children: 2.5 to 5.5 mg/dL
Hyperuricemia, the clinical term for elevated uric acid, is traditionally diagnosed above 7 mg/dL in men and above 6 mg/dL in women. However, a 2025 European expert consensus proposed a single threshold of 5.6 mg/dL for both sexes as a better marker of cardiovascular risk. Using that lower cutoff, the number of people classified as having elevated levels would roughly quadruple.
What Happens When Levels Get Too High
When uric acid concentration in your blood exceeds what your body fluids can keep dissolved, it begins to crystallize. These needle-shaped crystals, called monosodium urate crystals, tend to deposit in joints, especially in the big toe, ankles, and knees. The immune system treats these crystals as foreign invaders: white blood cells swallow them, triggering a cascade of inflammation that causes the intense, sudden pain of a gout attack. Joints become red, swollen, and extremely tender, sometimes overnight.
Uric acid also affects the kidneys. Uric acid stones account for 8% to 10% of all kidney stones and form when urine is consistently too acidic. Unlike calcium-based stones, uric acid stones can sometimes be dissolved by making the urine more alkaline, which is one reason your doctor might check urine pH if you’re prone to stones.
Links to Heart Disease and Metabolic Problems
Elevated uric acid doesn’t just cause gout and kidney stones. It plays a more insidious role in metabolic health. Inside cells, uric acid triggers oxidative stress in mitochondria (your cells’ energy-producing structures) and increases sensitivity to fat accumulation in the liver. Fructose metabolism generates uric acid inside liver cells, and that uric acid then boosts the activity of the very enzyme that processes fructose, creating a self-reinforcing cycle of fat and sugar storage.
Animal studies show that elevated uric acid raises blood pressure through several mechanisms: it reduces the availability of nitric oxide (a molecule that relaxes blood vessels), increases oxidative stress in vessel walls, and activates the hormonal system that regulates blood pressure and fluid balance. These findings help explain why high uric acid levels consistently show up alongside high blood pressure, insulin resistance, and elevated triglycerides in population studies.
Foods That Raise Uric Acid
Certain foods are particularly rich in purines and can push uric acid levels higher:
- Organ meats: liver, kidney, and sweetbreads are among the highest purine sources
- Certain seafood: anchovies, sardines, shellfish, and codfish
- Red meat: beef, lamb, and pork in large portions
- Alcohol: beer and distilled spirits carry the strongest association with gout risk
- High-fructose corn syrup: found in sweetened cereals, baked goods, some salad dressings, and canned soups
Dietary changes can help reduce flare-ups and modestly lower levels, but because most uric acid comes from internal metabolism rather than food, diet alone typically isn’t enough to treat established gout or bring very high levels into a safe range.
How High Uric Acid Is Treated
For people with gout or recurrent kidney stones, the primary goal of treatment is lowering the total amount of uric acid the body produces. The most commonly prescribed medications work by blocking the enzyme responsible for that final conversion of purines into uric acid. With that enzyme inhibited, less uric acid enters the bloodstream, and over time, existing crystal deposits can gradually dissolve.
These medications reduce both the dissolved uric acid circulating in your blood and the precipitated crystals already lodged in joints or tissues. Treatment is generally long-term, because uric acid levels rise again once medication stops. For kidney stones specifically, doctors may also prescribe supplements that make urine less acidic, which helps prevent new stones from forming and can dissolve existing ones.
Not everyone with elevated uric acid needs medication. Many people have levels above the traditional threshold without ever developing symptoms. Current guidelines generally reserve treatment for those who have symptomatic gout, kidney stones, or very high levels combined with cardiovascular risk factors. For people with mildly elevated levels and no symptoms, lifestyle changes like reducing alcohol, cutting back on high-purine foods, limiting fructose, and staying well hydrated are the typical first steps.