Benefits
Urinary measures with a lime juice and peel powder drink
In 173 Thai adults whose calcium oxalate stones had been removed, a lime juice and peel powder drink taken each evening for 2 years was followed by new stones in 14% versus 45% on placebo. Each sachet also supplies 21 mEq of potassium, and the full formula is not disclosed. The trial was registered only after it ended, and its groups were unequal (98 versus 75) despite planned equal allocation.
Urine pH with fresh lime juice compared with potassium citrate
In 47 healthy medical students, 10 mL of fresh lime juice in 250 mL of water three times a day for 7 days did not raise urine pH, while prescription potassium citrate did. Neither changed the urine calcium to creatinine ratio significantly. Each juice dose held 460 mg of citric acid versus 560 mg in each potassium citrate dose.
Sleep lab measures with a standardized lime peel extract
In 80 adults with disturbed sleep, 300 mg a day of a standardized lime peel extract for 2 weeks was reported to shorten the time to fall asleep, reduce time awake and raise sleep efficiency and total sleep time on overnight sleep recordings. The published summary does not say whether these changes differed from placebo, and a correction to the paper has been issued. Several authors list a supplement company affiliation.
Weight, blood sugar and blood fats with lime peel powder in teenagers
In 60 overweight or obese adolescents aged 10 to 18, daily capsules of dried Key lime peel and membrane powder for 4 weeks did not change body mass index, fasting blood sugar, blood fats, blood pressure or blood vessel markers compared with cornstarch capsules. The paper calls the fruit lemon, but it was Citrus aurantifolia.
Iron status with vitamin C from limeade at meals
In 36 iron-deficient women in rural Mexico eating a high-phytate diet, 500 mL of limeade with 25 mg of vitamin C at each of two meals a day for 8 months raised blood vitamin C but did not improve hemoglobin, ferritin or transferrin receptor levels compared with a lime-flavored drink without vitamin C or citric acid.
Vitamin C and citric acid content of the juice and fruit
USDA data list 30 mg of vitamin C and 25 kcal per 100 g of raw lime juice, and one lime yields about 44 g of juice, roughly 13 mg of vitamin C. A whole raw lime of 67 g holds about 19 mg. In laboratory analysis, fresh lime juice held 1.38 g of citric acid per ounce and lime juice concentrate 1.06 g.
Mechanism of action
Citric acid as a dietary source of urinary citrate
Citrate in urine helps keep calcium from crystallizing, and lime juice is rich in citric acid. Fresh juice delivers that citrate with little alkali, which may be why it did not raise urine pH in volunteers, while the Thai lime powder pairs citrate with potassium and raised urinary pH and citrate from baseline in patients.
Peel flavonoids and the GABA-A receptor in mice
In mice, the same standardized lime peel extract shortened the time to fall asleep and increased non-REM sleep. A flavonoid-rich fraction carried the effect, the extract bound to and activated GABA-A receptors in lab tests, and a GABA-A blocker abolished it. These are animal and laboratory findings, not results in people.
Furanocoumarins in the rind and the CYP3A4 enzyme
Lime rind held 6 to 182 times more furanocoumarins than the pulp, mostly bergapten. In lab tests lime juice contained more bergamottin than grapefruit juice and blocked the drug-processing enzyme CYP3A4. In people, quarter-strength lime juice did not change average levels of the drug felodipine, but more than doubled them in 2 volunteers.
Clinical trials
Double-blind, placebo-controlled trial at six Thai hospitals of a lime juice and peel powder (LPR) dissolved in water each evening, with a maltodextrin placebo; registered in the Thai Clinical Trials Registry in 2025 after follow-up ended in 2022. Funded by the National Research Council of Thailand; no competing interests declared. (Dissayabutra et al. 2025, PLoS One)
173 adults whose calcium oxalate stones had been removed, randomized 98 to LPR (7.75 g sachet with 63 mEq citrate, 21 mEq potassium and 153 mg of flavonoids; full formula not disclosed) and 75 to placebo; 151 completed.
Stones recurred on CT in 14% with LPR versus 45% with placebo over 2 years (13 of 86 versus 33 of 65 completers, 15.1% versus 50.8%, in the results section) (hazard ratio 0.24, 95% CI 0.13 to 0.44). Urinary protein and IL-8 fell with LPR versus placebo among completers. No serious adverse events; transient tooth sensitivity was reported. Complete urine chemistry was not available for all participants, and the arms were unequal despite planned 1:1 randomization.
Phase 2 randomized, double-blind, placebo-controlled trial of the same Thai lime powder regimen (LPR), a limeade-based supplement containing potassium and citrate. Funding not stated in the abstract. (Ungjaroenwathana et al. 2019, Nephrology (Carlton))
74 adults with kidney stones at high risk of recurrence, randomized to LPR or placebo for 6 months.
The abstract reports that LPR raised urinary pH, citrate and potassium, lowered urinary calcium, oxalate and supersaturation, and raised urinary antioxidant status; it does not give between-group statistics. Gastrointestinal side effects were rare, and no participant formed a new stone during the trial.
Randomized three-arm study of a drink made from an in-house lime powder, prescription potassium citrate, or a lactose placebo, with the lime powder and potassium citrate matched for potassium (21 mEq) and citrate (63 mEq). Supported by non-US government funding. (Tosukhowong et al. 2008, Urol Res)
31 Thai adults with kidney stones: 13 on lime powder, 11 on potassium citrate and 7 on placebo.
Urinary pH, potassium and citrate rose in both the lime powder and potassium citrate groups, while the placebo group was unchanged apart from urinary chloride. Lime powder also raised red cell glutathione and lowered urinary malondialdehyde and two tubular damage markers. Results are reported within groups, and the groups were small.
Prospective, single-center, unblinded randomized crossover study of 7 days of fresh lime juice versus mist potassium citrate, with a 2-week washout. Funded by a university research grant. (Sivananthan et al. 2023, Malays Fam Physician)
50 healthy medical student volunteers in Kuala Lumpur, Malaysia; 47 analyzed after 3 withdrew because of the taste of potassium citrate. Lime juice dose was 10 mL in 250 mL of water three times daily.
Potassium citrate raised urine pH (6.2 to 6.7), while lime juice did not (5.9 after treatment, P = 0.148). Neither treatment changed the urine calcium to creatinine ratio significantly. Lime juice caused no gastrointestinal side effects. Fluid, protein and salt intake were not controlled.
Randomized, double-blind, placebo-controlled trial with overnight polysomnography. Several authors list Nutra-it Inc. research affiliations, and the corresponding author reports funding from the Korea Ministry of SMEs and Startups. A correction was published in September 2025 (Phytomedicine 145:156978); its content is not shown in PubMed. (Kim et al. 2025, Phytomedicine)
80 adults with sleep disturbance in Korea, given 300 mg a day of standardized lime peel extract or placebo for 2 weeks.
The abstract reports that the extract significantly improved overnight sleep recordings, with shorter sleep latency, wake after sleep onset and total wake time and higher sleep efficiency, total sleep time and stage 2 sleep, and lower Epworth daytime sleepiness scores. It does not say whether these were differences from placebo or from baseline. No serious adverse effects were reported. A single short trial of one extract.
Triple-masked, randomized, placebo-controlled trial of capsules of dried peel and outer membrane of Citrus aurantifolia (called lemon in the paper) versus cornstarch capsules; the dose is not stated. Funded as a thesis by Isfahan University of Medical Sciences. (Hashemipour et al. 2016, Med J Islam Repub Iran)
60 overweight or obese adolescents aged 10 to 18 in Isfahan, Iran; 30 and 29 completed.
No between-group differences in body mass index, fasting blood sugar, blood lipids, blood pressure, ICAM-1 or VCAM-1. Within the peel group, body mass index, LDL cholesterol and systolic pressure fell slightly. Low compliance kept the trial to 4 weeks.
Community trial in which two rural Mexican populations were randomly assigned to limeade providing 25 mg of vitamin C or a lime-flavored placebo drink free of vitamin C and citric acid, taken with two meals a day, 6 days a week. PubMed lists US government support. (Garcia et al. 2003, Am J Clin Nutr)
36 iron-deficient women, 18 per group, eating diets high in phytate and nonheme iron.
Plasma vitamin C was higher in the limeade group at every check. After adjusting for starting values, hemoglobin, plasma ferritin, transferrin receptors and their ratio did not differ between groups at 8 months. The extra vitamin C did not improve iron status.
Randomized crossover pharmacokinetic study of the blood pressure drug felodipine taken with 250 mL of grapefruit juice, one quarter-strength lime juice, red wine or water, with laboratory tests of CYP3A4 inhibition. Supported by non-US government funding. (Bailey et al. 2003, Clin Pharmacol Ther)
Healthy volunteers; the number is not given in the abstract.
Grapefruit juice nearly doubled average felodipine exposure (AUC 55 versus 29 nmol.h/L with water). Quarter-strength lime juice did not change average values, but more than doubled felodipine exposure and peak level in 2 participants, and individual responses to lime and grapefruit juice were closely correlated. Lime juice held 100 versus 25 micromol/L of bergamottin.