Drinking lemon water every day may lower the risk of certain kidney stones forming, according to Verywell Health, though the drink does not "cleanse" the kidneys of toxins and people with severe chronic kidney disease should be careful with it.
Lemon water may help prevent calcium oxalate stones, the most common type of kidney stone, which form when minerals in urine become too concentrated and crystallize. Lemon juice contains citric acid, which the body converts into citrate. Citrate can bind to calcium in urine, preventing calcium and oxalate from forming crystals and slowing the growth of small crystals already present.
A 2021 study of 203 adults with calcium oxalate stones found that drinking 60 milliliters of fresh lemon juice twice a day lowered the risk of stones forming again by 38 percent. The effect weakened over time, however, because most participants found it hard to keep up the routine.
Why drinking enough fluid matters
Lemon water is often marketed as a "detox" drink, but lemons are not needed to remove toxins from the body. The National Institute of Diabetes and Digestive and Kidney Diseases says healthy kidneys already filter blood, remove waste and regulate fluid and electrolyte levels on their own.
What matters most for preventing stones is drinking enough fluid overall, whether or not it contains lemon. Experts recommend drinking enough to produce at least 2 liters of urine a day, spread evenly through the day and night to avoid mineral concentration spikes. One article on fluid intake for preventing urinary tract stones put the daily fluid target at about 3.7 liters for healthy adult men and about 2.7 liters for women.
Lemon water does not prevent every type of stone
Citrate mainly helps with calcium oxalate stones; other stone types respond differently. Uric acid stones form in overly acidic urine, where raising urine pH and cutting purine-rich foods such as organ meats and seafood matter more than fluid intake alone. Struvite stones are usually linked to urinary tract infections and often require antibiotics or removal. Cystine stones occur in people with cystinuria, a rare inherited condition, and need very high fluid intake, urine alkalization and specialist supervision.
Doctors typically analyze stones after repeat cases, sometimes with 24-hour urine testing, to find causes such as low citrate, low urine volume or high calcium, oxalate or uric acid levels.
Risks of lemon juice
Lemon juice is generally considered safe, especially diluted with water. But large amounts, up to half a cup a day, can damage tooth enamel. Lemon juice has a pH of about 2.25, and citric acid at pH 2.7 or lower can cause noticeable enamel erosion, according to research on citric acid's effects on enamel surfaces. Excessive intake can also cause heartburn, acid reflux and upper abdominal pain.
Lemon water and chronic kidney disease
Lemon water is not inherently dangerous for people with chronic kidney disease. However, those at stages 4 and 5 need to limit fluid intake and should discuss lemon water with their doctor. Potassium levels may also need monitoring, since severely damaged kidneys can let potassium build up to dangerous levels, and lemon juice's modest potassium content can add up with heavy use.
