Lime: what the kidney stone trials actually tested

The strongest results on limes come from kidney stone trials in Thailand, and none of them gave anybody fresh limes. They used a powder made from limeade, taken as a supplement. In the largest, 173 people who had just had calcium oxalate stones removed took it for two years, and stones came back in 14 percent of them against 45 percent on placebo. In a smaller trial the powder raised citrate in the urine as well as the same dose of potassium citrate did. That trial had 31 people and measured markers in the urine, not whether stones came back, and each powder dose carried 21 mEq of potassium, so it is no reason to swap a prescribed potassium citrate for it. Citrate is what doctors try to raise in people whose urine runs low in it and who keep forming stones. Whether squeezing limes into your food does any of this has not been tested. A 2026 review of 31 studies on people with recurring stones noted possible minor side effects with lemon juice, and even that rests on low-strength evidence. As a source of vitamin C a lime is modest. One whole fruit of 65 g gives about 19 mg and a wedge about 2 mg.

The numbers, per 100 g

How much is actually in it

• British composition data give lime flesh 46 mg vitamin C per 100 g, 58% more than the 29.1 mg in the USDA record, a gap that reflects different samples and methods. — CoFID 2021 entry 14-131 against USDA SR Legacy FDC 168155 (n = one entry each) Evidence E source
  Vitamin C 46 mg (CoFID) vs 29.1 mg (USDA) per 100 g

What a real portion looks like

• One whole lime of 65 g gives about 19 mg vitamin C and a wedge of 8 g about 2 mg, so a squeeze on a meal adds little vitamin C. — US household measures, FNDDS (n = FNDDS 5,432 foods) Evidence E source
  1 fruit 65 g 18.9 mg, 1 wedge 8 g 2.3 mg, fresh lime juice 30 mg per 100 g

What your body absorbs

• In an 8-month community trial with 36 iron-deficient Mexican women, limeade adding 25 mg vitamin C to each of 2 daily meals did not improve hemoglobin or ferritin. — Iron-deficient women in rural Mexico eating high-phytate, nonheme-iron diets (n = 36) Evidence B source
  No final difference in hemoglobin, ferritin or transferrin receptors vs placebo beverage

What it does to your health

• In a 24-month randomised placebo-controlled trial in 173 Thai patients after calcium oxalate stone removal, a lime-based citrate supplement cut 2-year stone recurrence from 45% to 14% (HR 0.24). — Adults with calcium oxalate urolithiasis after successful stone removal, six hospitals in Thailand (n = 173 enrolled, 151 completed) Evidence B source
  Recurrence 14% vs 45% at 2 years, HR 0.24 (0.13-0.44)
• In a 6-month randomised double-blind trial in 74 kidney stone patients, a limeade-based powder raised urinary pH, citrate and potassium and lowered urinary calcium and oxalate compared with placebo. — Urolithiasis patients at high risk of recurrence, Thailand (n = 74) Evidence B source
  Urinary pH, citrate and potassium up, calcium and oxalate down; no stone recurrence during 6 months
• In a trial in 31 stone patients, lime powder carrying 21 mEq potassium and 63 mEq citrate raised urinary citrate and pH as well as the same dose of potassium citrate. — Nephrolithiasis patients: lime powder 13, potassium citrate 11, placebo 7 (n = 31) Evidence B source
  Urinary pH, potassium and citrate rose equally in lime and potassium citrate groups

Safety, limits and interactions

• In a randomised crossover pharmacokinetic study, quarter-strength lime juice did not change average felodipine levels, but it more than doubled drug exposure in 2 volunteers, and lime juice held 4 times more bergamottin than grapefruit juice. — Healthy volunteers taking felodipine with juice, wine or water Evidence B source
  Mean felodipine AUC unchanged with lime juice, doubled in 2 subjects; bergamottin 100 vs 25 micromol/L
• During the 1996 cholera epidemic in Guinea-Bissau, people who had lime juice in the sauce eaten with rice had 69% lower odds of cholera (OR 0.31), and lime juice stopped Vibrio cholerae growing in the same meals in the lab. — Hospitalised cholera cases and matched controls, Bissau Evidence C source
  OR 0.31 (0.17-0.56) for lime juice in sauce

Who this works differently for

• An Italian urology working group lists limes with lemons, oranges and grapefruit as natural sources of dietary citrate for stone formers with low urinary citrate. — Kidney stone formers with hypocitraturia Evidence E source
  Position statement, no pooled estimate

What is still unknown

• In a 2-week randomised placebo-controlled trial in 80 adults with poor sleep, a standardised lime peel extract at 300 mg a day shortened sleep latency and improved sleep efficiency on polysomnography. — Adults with sleep disturbance (n = 80) Evidence B source
  Shorter sleep latency and wake time, higher sleep efficiency and total sleep time vs placebo
• A 2026 systematic review of 31 studies on recurrent kidney stones, 26 of them randomised, noted possible minor adverse events with lemon juice, at low strength of evidence. — Nonpregnant adults and children with recurrent kidney stones (n = 31 studies (26 RCTs)) Evidence A source
  Possible increase in minor adverse events with lemon juice (low strength of evidence)

The bottom line

Use lime because you like the taste. Do not count on it for vitamin C. If you are low in iron and eat a diet heavy in phytate, the compounds in whole grains and beans that block iron, limeade did not help in the one trial that tested it. In rural Mexico, iron-deficient women drank limeade that added 25 mg of vitamin C to two meals a day for eight months, and their hemoglobin and iron stores ended up no different from a placebo drink. How much vitamin C a lime holds is itself uncertain. British composition tables give 46 mg per 100 g and the USDA record 29.1 mg, a gap that comes from different samples and methods. If you have had stones, an Italian urology working group lists limes with lemons, oranges and grapefruit as natural sources of citrate. That is an expert opinion without pooled data behind it, and the same 2026 review noted possible minor side effects with lemon juice (lemon, not lime), so the lime powder from the Thai trials and a glass of juice at home are two different things to discuss with your urologist. If you take felodipine, a blood pressure drug, be careful with lime juice. In one crossover study, lime juice diluted to a quarter of its strength left average drug levels unchanged, yet more than doubled them in two volunteers, and the lime juice held four times more bergamottin than grapefruit juice. Two findings are interesting and thin. During the 1996 cholera epidemic in Guinea-Bissau, people who ate lime juice in the sauce on their rice had 69 percent lower odds of cholera, and lime juice stopped the bacteria growing in the same meals in the lab. That is one observational study in one outbreak. It shows a link and cannot show that the lime did the protecting. A peel extract at 300 mg a day improved sleep in 80 adults with poor sleep over two weeks, measured in a sleep lab. That was a standardised extract of the peel, a product you cannot make in a kitchen, and one two-week trial is too short to build a habit on. We found no study on limes in pregnancy, in children, or in people with kidney disease who have to watch their potassium, so this page has nothing to tell those readers either way.

Sources

1. lim-b5-11 · reference dataset
   CoFID 14-131 Limes, flesh only: Vitamin C 46 mg per 100 g · USDA FDC 168155 Limes, raw: vitamin C 29.1 mg per 100 g
   CoFID 2021, Public Health England / OGL v3.0 · checked 2026-09-23
2. lim-b5-10 · reference dataset
   FNDDS 2709170 Lime, raw: Vitamin C 29.1 mg/100 g, 1 fruit 65 g 18.9 mg, 1 slice or wedge 8 g 2.3 mg · FNDDS 2709184 Lime juice, 100%, freshly squeezed: Vitamin C 30 mg/100 g
   USDA FNDDS 2021-2023 · checked 2026-09-23
3. lim-b5-04 · RCT
   Two rural Mexican populations were randomly assigned to an AA or a placebo group, each with 18 iron-deficient women. The AA group was given 500 mL limeade containing 25 mg AA twice a day, 6 d/wk, for 8 mo. ... CONCLUSION: Increasing dietary AA by 25 mg at each of 2 meals/d did not improve iron status in iron-deficient women consuming diets high in phytate and nonheme iron.
   Am J Clin Nutr, 2003 · checked 2026-09-23
4. lim-b5-01 · RCT
   173 patients with calcium oxalate urolithiasis who had undergone successful stone removal were enrolled from six hospitals in Thailand. ... The recurrence rate at 2 years was significantly lower in the LPR group (14%) compared to placebo (45%) (p < 0.001). Kaplan-Meier analysis demonstrated a hazard ratio (HR) of 0.24 (95% CI: 0.13-0.44; log-rank p < 0.0001) favoring LPR.
   PLoS One, 2025 · checked 2026-09-23
5. lim-b5-02 · RCT
   Seventy-four urolithiasis patients were randomly allocated to receive either LPR or placebo for 6 months in a double-blinded manner. ... Administration of LPR significantly increased urinary pH, citrate and potassium excretion. Urinary levels of calcium and oxalate, and plasma protein carbonyl content were reduced
   Nephrology (Carlton), 2019 · checked 2026-09-23
6. lim-b5-03 · RCT
   Lime powder and potassium citrate contained equal amounts of potassium (21 mEq) and citrate (63 mEq). After treatment, there was an increase in urinary pH, potassium and citrate in Group 1 and 2. ... In conclusion, consumption of our in-house lime powder exerted citraturic and alkalinizing actions as efficient as consumption of potassium citrate.
   Urol Res, 2008 · checked 2026-09-23
7. lim-b5-05 · RCT
   Bergamottin concentrations in grapefruit and lime juices were 25 and 100 micromol/L, respectively. ... One quarter-strength lime juice did not alter mean values. ... One quarter-strength lime juice more than doubled felodipine AUC and plasma peak drug concentration in 2 subjects.
   Clin Pharmacol Ther, 2003 · checked 2026-09-23
8. lim-b5-08 · case-control
   Lime juice in the sauce eaten with rice gave a strong protective effect (odds ratio [OR] = 0.31, 95% confidence interval [CI] = 0.17-0.56) ... V. cholerae thrives in rice with peanut sauce, but lime juice inhibited its growth.
   Trop Med Int Health, 2000 · checked 2026-09-23
9. lim-b5-09 · guideline
   Citrus (lemons, oranges, grapefruit, and lime) and non citrus fruits (melon) are natural sources of dietary citrate, and several studies have shown the potential of these fruits and/or their juices in raising urine citrate levels.
   Arch Ital Urol Androl, 2015 · checked 2026-09-23
10. lim-b5-06 · RCT
    The randomized, double-blind, placebo-controlled clinical trial involved 80 subjects who received either SLPS (300 mg/day) or placebo for a 2-week period. RESULTS: SLPS significantly improved polysomnographic outcomes, including a reduction in sleep latency, wake after sleep onset, and total wake time, and enhancement of sleep efficiency, total sleep time, and stage 2 sleep.
    Phytomedicine, 2025 · checked 2026-09-23
11. lim-b5-07 · systematic review
    Among 31 studies (26 RCTs and 5 NRSIs), none evaluated imaging strategies. ... There may be increased minor adverse events with lemon juice but no increased harm due to serious adverse events with thiazides and allopurinol (low SOE).
    Ann Intern Med, 2026 · checked 2026-09-23