Reducing calcium in your urine comes down to a combination of dietary changes, adequate hydration, and sometimes medication. The threshold for “too much” calcium in urine is generally above 300 mg per day for women and 400 mg for men, measured through a 24-hour urine collection. If your levels are elevated, the good news is that several straightforward strategies can bring them down significantly.
Why Urine Calcium Matters
Excess calcium in urine, called hypercalciuria, is a primary driver of calcium-based kidney stones. When the concentration of calcium rises high enough, it can combine with oxalate or phosphate to form crystals in the urinary tract. Lowering urine calcium reduces this supersaturation and lowers your risk of forming new stones.
Cut Back on Sodium
Salt is one of the biggest dietary levers for urine calcium. Sodium and calcium compete for the same transport pathways in the kidneys, so when you eat more salt, your kidneys excrete more calcium along with it. High sodium intake also causes volume expansion in the blood, which further pushes calcium into the urine. The general target for people with hypercalciuria is under 2,300 mg of sodium per day, and many kidney stone specialists recommend staying closer to 1,500 mg.
Most excess sodium comes from processed foods, restaurant meals, canned soups, deli meats, and salty snacks rather than the salt shaker at the table. Reading nutrition labels and cooking more at home are the most effective ways to get sodium under control. This single change can meaningfully reduce urine calcium for many people.
Limit Animal Protein
Diets high in animal protein increase the acid load your body has to process. Your bones buffer that acid by releasing calcium, which then ends up in the urine. Animal protein also raises uric acid excretion, another risk factor for stone formation. A landmark randomized trial found that men with hypercalciuria who followed a low-animal-protein, low-sodium, normal-calcium diet had fewer recurrent stones than those simply placed on a low-calcium diet.
This doesn’t mean you need to eliminate meat or fish entirely. The goal is moderation: keeping animal protein to roughly 0.8 to 1.0 grams per kilogram of body weight per day, rather than the 1.4 g/kg average many Americans consume. All animal proteins contribute to this effect, including fish, so limiting overall intake rather than swapping one source for another is the better approach.
Don’t Restrict Dietary Calcium
This is the part that surprises most people. If you have too much calcium in your urine, your instinct might be to eat less calcium. That strategy backfires. For years, doctors gave exactly that advice, and it led to both weaker bones and more kidney stones.
The reason is oxalate. When you eat calcium with your meals, it binds to oxalate in your gut and forms an insoluble compound that passes through your stool. When calcium intake drops, more oxalate stays dissolved, gets absorbed into the bloodstream, and ends up in your urine, where it combines with whatever calcium is there to form stones. There’s a clear inverse relationship: the less calcium in your diet, the more oxalate your body absorbs, with absorption rates ranging from about 2% on higher calcium diets up to nearly 17% when calcium is very low.
The recommended intake for stone formers is 800 to 1,200 mg of calcium per day from food sources, spread across meals. Eating calcium-rich foods at the same time as higher-oxalate vegetables maximizes the binding effect in your gut. Dairy products, fortified plant milks, and leafy greens like kale and bok choy are good sources.
Eat More Potassium-Rich Foods
Potassium citrate, whether from food or supplements, reduces urine calcium through several mechanisms at once. Citrate binds calcium in both the intestine and the urine, pulling it out of the pool that could form stones. When your body metabolizes citrate into bicarbonate, it creates a more alkaline environment that directly slows bone calcium release and helps the kidneys reabsorb calcium instead of dumping it into urine. On top of that, higher citrate levels in urine mean there’s a natural inhibitor present that prevents calcium crystals from growing.
Fruits and vegetables are the best dietary sources. Oranges, bananas, potatoes, tomatoes, avocados, and leafy greens are all high in potassium and citrate precursors. For people who can’t get enough through food alone, potassium citrate supplements are commonly prescribed and have been shown to both lower urine calcium and raise urine citrate effectively.
Drink Enough Fluids
Hydration doesn’t change how much calcium your kidneys excrete, but it dilutes the concentration so crystals are less likely to form. The standard recommendation is to drink enough to produce 2 to 2.5 liters of urine per day, which typically means consuming about 2.5 to 3 liters of fluid. One study found that adding 1.3 liters of water on top of normal intake was enough to reach protective urine volumes for most people.
Water is the best choice. Spreading your intake throughout the day, including before bed, keeps urine dilute around the clock. You can gauge your hydration by urine color: pale yellow is the target.
Keep Oxalate Intake in Check
While this article focuses on calcium, managing oxalate alongside calcium gives you the best results. Keeping dietary oxalate below 100 mg per day while maintaining 1,000 to 1,200 mg of calcium is the combination researchers have identified as most effective for reducing the urinary building blocks of stones. High-oxalate foods include spinach, rhubarb, beets, nuts, chocolate, and sweet potatoes. You don’t need to avoid these entirely, but eating them alongside calcium-rich foods helps neutralize their impact.
When Medication Is Needed
If dietary changes aren’t enough to bring urine calcium into a safe range, thiazide-type diuretics are the standard medication. These drugs tell the kidneys to reabsorb more calcium back into the bloodstream instead of letting it pass into the urine. In clinical studies, both hydrochlorothiazide (25 mg daily) and indapamide (2.5 mg daily) produced significant reductions in urine calcium, and randomized trials have consistently shown they reduce the rate of new stone formation. These medications are generally well tolerated at starting doses and may also help preserve bone density, an added benefit for people losing calcium through their urine.
Rule Out Underlying Conditions
Sometimes high urine calcium isn’t just a dietary problem. Primary hyperparathyroidism, a condition where one or more of the parathyroid glands in your neck become overactive, is one of the most common medical causes. In about 80% of cases, a benign tumor called an adenoma causes a single gland to overproduce parathyroid hormone, which pulls calcium from bone into the blood and ultimately into the urine. If your blood calcium is consistently elevated alongside high urine calcium, this condition is worth investigating. Surgery to remove the overactive gland is curative in most cases and is recommended for patients under 50, those with kidney stones, or those with reduced bone density.
Other potential causes include excess vitamin D supplementation, certain medications, and conditions that increase bone turnover. A 24-hour urine collection along with blood calcium and parathyroid hormone levels can help pinpoint the cause.
How to Get Accurate Urine Calcium Results
A 24-hour urine collection is the standard test. You’ll discard your first morning void and record the time, then collect every drop of urine for the next 24 hours, finishing with a void at the same time the following morning. The collection container should be refrigerated throughout. Completeness is critical: missing even a single void throws off the results. Some people find it helpful to place a reminder note on the toilet seat or set phone alarms. Eat and drink normally during the collection so the results reflect your typical habits. Your lab will report total calcium in milligrams per 24 hours, which you can compare against reference ranges to see where you stand.