Lemon juice: tested against kidney stones, not yet proven

Most of the research on lemon juice is about kidney stones. A 2026 systematic review of 31 studies in people with stones found that lemon juice may increase minor side effects, with low strength of evidence. The largest trial gave 203 adults with calcium oxalate stones 2 fl oz (60 ml) of fresh lemon juice twice a day on top of a standard diet. Over two years 21.0% had a new stone against 31.1% on the diet alone, a hazard ratio of 0.62 (95% CI 0.35 to 1.07) that did not reach significance. The same open trial recorded gastrointestinal complaints in 37% of the lemon group against 7.8% of controls, with heartburn in 21 people against 1. In a smaller randomized trial in 30 patients with low urinary citrate, about 2.9 fl oz (85 ml) of lemon juice a day for 3 months raised urinary citrate 2.5-fold, while potassium citrate, the drug, raised it 3.5-fold. That trial measured urine chemistry, not new stones.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• Fresh lemon juice carries about 36 to 39 mg of vitamin C per 3.5 oz (100 g) in the US and UK food tables, while folate differs by a third, 20 against 13 micrograms, and neither table records a sample range. — Lemon juice, raw (FDC 167747, SR Legacy) against Lemon juice, fresh (CoFID 14-277) (n = 1 USDA record and 1 CoFID record, no Foundation samples, so no measured spread) Evidence E source
  Vitamin C 38.7 mg per 3.5 oz (100 g) in USDA against 36 mg in CoFID, a 7% gap; folate 20 against 13 micrograms, a 35% gap; vitamin B6 0.046 against 0.05 mg; CoFID energy 7 calories and total sugars 1.6 g per 3.5 oz (100 g)

What a real portion looks like

• The juice of one lemon weighs 1.7 oz (47 g) in the US dietary survey, which at the SR Legacy value gives about 18 mg of vitamin C, and a wedge squeezed over food gives only 6 g of juice. — household measures for Lemon juice, 100%, freshly squeezed in the USDA food and nutrient database for dietary studies (n = 8 household measures for FNDDS code 61204010) Evidence E source
  Juice of 1 lemon 47 g; juice of 1 wedge or slice 6 g; 1 fl oz 31 g; quantity not specified 8 g; 47 g x 38.7 mg per 3.5 oz (100 g) = about 18 mg vitamin C

What cooking and storage change

• When citrus fruit is cooked, the USDA table for Fruits and Fruit Juices keeps 95% of vitamin C and 70% of folate, and it has no separate factor for juice added to a hot dish. — USDA Table of Nutrient Retention Factors, Release 6 (2007), method FRUITS,CITRUS,CKD, group Fruits and Fruit Juices (n = 1 method row, code 270, table dated Sep 1975) Evidence E source
  Vitamin C 95% retained; folate 70% retained; thiamin, riboflavin, niacin, vitamin B6 95%; minerals 100%

What it does to your health

• A 2021 meta-analysis of 11 randomized trials with 512 people found orange juice or its flavonoid hesperidin did not change body weight, BMI, fat mass or waist. — participants in RCTs of orange juice and/or hesperidin supplementation (n = 512) Evidence A source
  Body weight WMD -0.68 lb (95% CI -3.2 to 1.8; metric: -0.31 kg, -1.44 to 0.82); BMI 0.11 kg/m2 (-0.33 to 0.56); fat mass 0.31 lb (-2.1 to 2.7; metric: 0.14 kg, -0.95 to 1.22); waist 0.03 in (-0.46 to 0.51; metric: 0.07 cm, -1.16 to 1.30)
• In a crossover trial, 8.5 fl oz (250 mL) of lemon juice with bread lowered the blood glucose peak by 30% and delayed it, but did not change how much people ate 3 hours later. — healthy adults Evidence B source
  Glucose peak -30% (p < 0.01), delayed 78 vs 41 min; no effect of any beverage on ad libitum energy intake
• In a randomized crossover trial in healthy adults, 8.5 fl oz (250 ml) of lemon juice with 3.5 oz (100 g) of bread lowered the blood glucose peak by 30% and delayed it from 41 to 78 minutes compared with water, with no change in later energy intake. — healthy adults, single test meals of 100 g bread with 8.5 fl oz (250 ml) water, black tea or lemon juice, glucose followed for 180 min (n = not stated in the abstract) Evidence B source
  Glucose peak 30% lower (p < 0.01); peak at 78 vs 41 min with water (p < 0.0001); no effect on ad libitum energy intake 3 h later

Safety, limits and interactions

• In a Finnish case-control study of 206 people, eating citrus fruits more than twice a day carried 37 times the adjusted odds of dental erosion. — 106 cases with dental erosion and 100 randomly selected controls from the same source population (n = 206) Evidence C source
  Citrus fruits more than twice a day AOR 37; apple vinegar weekly AOR 10; soft drinks daily AOR 4
• A 2024 meta-analysis of observational studies linked eating acidic foods to 2.4 times the odds of erosive tooth wear in permanent teeth. — people in 71 observational studies of erosive tooth wear in permanent dentition (n = 71 studies) Evidence C source
  Acidic foods OR 2.40 (95% CI 1.44 to 4.00); regurgitation OR 2.27; carbonated drinks OR 1.43
• In a lab study, canned lemon juice was among acidic products that showed great erosive potential on children's baby tooth enamel, with damage growing with exposure time. — human deciduous teeth exposed in vitro Evidence D source
  Loss of gloss, color change and irregular enamel loss, increasing with incubation time
• In the same 2-year randomized trial, 37% of people drinking 4.1 fl oz (120 ml) of fresh lemon juice a day reported gastrointestinal complaints against 7.8% on diet alone, mostly heartburn in 21 against 1. — 203 adults with calcium oxalate stones, 100 on 2 fl oz (60 ml) fresh lemon juice twice daily, 103 on diet alone, 2 years (n = 203) Evidence B source
  Gastrointestinal disorders 37.0% vs 7.8% (p<0.001); heartburn 21 vs 1 patients (p<0.001); 2 of 37 stopped lemon juice permanently; no serious adverse events in the lemon juice group
• A 2026 systematic review of 31 studies on preventing kidney stone recurrence found that lemon juice may increase minor adverse events, with low strength of evidence, and did not list it among the measures that may prevent recurrence. — 31 studies (26 RCTs and 5 nonrandomised studies) in nonpregnant adults or children with nephrolithiasis (n = 31 studies) Evidence A source
  Possible increase in minor adverse events with lemon juice, low strength of evidence; no size reported in the abstract
• Laboratory data suggest that 5 minutes of lemon juice on extracted tooth roots raises dentin permeability, as other acidic drinks do, and that brushing afterward lowers it again. — root segments of 25 extracted third molars, 5 per acidic substance (n = 25 teeth) Evidence D source
  All acidic substances including lemon juice significantly increased dentin permeability (p< 0.05); toothbrushing with or without dentifrice decreased it

What people believe that the data does not support

• The EU health-claims register has no authorized claim for lemon. Both lemon claims filed, on digestion and antioxidant action, are non-authorized, and none was filed for weight. — EU register on nutrition and health claims, snapshot 2026-09-21 Evidence E source
  0 authorized, 2 non-authorized lemon claims; no weight claim filed
• In a randomized trial in 84 overweight women, a short diet of lemon juice mixed with maple and palm syrups cut weight and body fat more than no restriction, as did a calorie-matched placebo diet, and the authors attribute the loss to calorie restriction. — 84 overweight premenopausal Korean women, lemon detox diet vs pair-fed placebo diet vs no restriction, 11 days in total (n = 84) Evidence B source
  Changes in body weight, BMI, body fat and waist-hip ratio significantly greater in both the lemon detox and pair-fed placebo groups than in controls; hs-CRP fell only in the lemon detox group
• The EU refused to authorize the claim that lemon helps support digestion and digestive juice flow, and the US 21 CFR health claims contain no entry for lemon juice. — EU Register on nutrition and health claims, substance Citrus limon (Lemon) (n = 1 claim, status non-authorized) Evidence E source
  The digestion claim for lemon is non-authorized in the EU; no authorized claim for lemon exists in the register

Who this works differently for

• In an 11-day trial of 84 overweight Korean women, a 7-day very low calorie diet of lemon juice and syrups, like a calorie-matched placebo diet, cut weight and body fat more than eating without restriction. — premenopausal overweight Korean women (n = 84) Evidence B source
  Changes in body weight, BMI, body fat percentage and waist-hip ratio significantly greater in both lemon detox and pair-fed placebo groups than in unrestricted controls
• In a randomized trial in 30 patients with low urinary citrate and calcium stones, about 2.9 fl oz (85 ml) of fresh lemon juice a day for 3 months raised urinary citrate 2.5-fold, against 3.5-fold with potassium citrate and 0.8-fold with diet advice alone. — 30 patients with hypocitraturic urinary calcium stones, 3 groups of 10, 3 months (n = 30) Evidence B source
  Urinary citrate 2.5-fold increase with lemon juice, 3.5-fold with potassium citrate, 0.8-fold with dietary recommendations; urinary calcium fell only in the lemon juice and potassium citrate groups
• In a randomized trial in 203 adults with calcium oxalate stones, 2 fl oz (60 ml) of fresh lemon juice twice daily was followed by stone recurrence over 2 years in 21.0% against 31.1% on diet alone, a hazard ratio of 0.62 that did not reach significance. — 203 adults with recurrent calcium oxalate nephrolithiasis on a standardized diet, 100 randomized to lemon juice, 103 to diet alone, 2 years (n = 203) Evidence B source
  Recurrence 21.0% vs 31.1% at 2 years, HR 0.62 (95% CI 0.35 to 1.07), p = 0.089; at 1 year HR 0.43 (0.20 to 0.89), p = 0.028
• In 9 patients with thyroid cancer given radioiodine, lemon juice used to stimulate saliva lowered the potential radiation dose to the parotid glands by 34.2% on average and caused no rebound uptake. — 9 patients with differentiated thyroid cancer, 18 parotid glands, salivary scans with and without lemon juice before radioiodine therapy (n = 9) Evidence C source
  Mean relative decrease in potential radiation absorbed dose 34.2% +/- 17.4% (range 3.1 to 66.1%); no rebound effect
• In a 6-week randomized crossover trial in 24 people with blocked urinary catheters, drinking lemon juice widened the safety margin against catheter encrustation by 0.84 pH units, more than extra fluid or potassium citrate. — 24 patients with catheter blockage, each receiving increased fluid intake, lemon juice and potassium citrate in random order, 6 weeks (n = 24) Evidence B source
  Safety margin increase 0.84 (95% CI 0.63 to 1.04) with lemon juice, 0.57 (0.37 to 0.78) with increased fluid, 0.41 (0.20 to 0.61) with potassium citrate

What is still unknown

• A 2020 meta-analysis of 13 randomized trials with 921 adults found citrus fruit or citrus extracts lowered body weight by about 2.9 lb (1.3 kg), with very high heterogeneity between trials. — adults in RCTs of citrus and/or its extracts for at least 4 weeks (n = 921) Evidence A source
  Body weight -2.8 lb (95% CI -4 to -1.6; metric: -1.28 kg, -1.82 to -0.74), I2 81.4%; BMI -0.32 kg/m2; waist -0.86 in (-2.19 cm); no effect on waist-to-hip ratio or body fat
• The authors of the Korean lemon juice diet trial attributed the drop in body fat and insulin resistance to calorie restriction during the 7-day program. — premenopausal overweight Korean women (n = 84) Evidence B source
  Body fat and insulin resistance reduced through caloric restriction; hs-CRP fell only in the lemon group
• In rats on a high-fat diet, a lemon product fermented with Lactobacillus lowered body weight by 9.7% and fat tissue by 25.7%, a result not tested in people. — Wistar rats fed a high-fat diet, and 3T3-L1 adipocytes Evidence D source
  Body weight -9.7%, fat tissue weight -25.7%, serum TG -17.0% in rats

The bottom line

In the kitchen the amounts are small. The juice of one lemon weighs 1.7 oz (47 g) in the US dietary survey, which works out to about 18 mg of vitamin C at the USDA value per 3.5 oz (100 g), and a wedge squeezed over food gives 6 g of juice. US and UK tables agree on vitamin C, 38.7 against 36 mg per 3.5 oz (100 g), and differ by a third on folate, 20 against 13 micrograms, with no sample range in either. Cooking citrus keeps 95% of the vitamin C and 70% of the folate by the USDA group factor from 1975, which has no separate figure for juice stirred into a hot dish. How much vitamin C an opened bottle loses in the fridge is not in the data we found. In a randomized crossover trial in healthy adults, 8.5 fl oz (250 ml) of lemon juice drunk with 3.5 oz (100 g) of bread lowered the blood glucose peak by 30% and pushed it from 41 to 78 minutes compared with water. That was a single meal, the abstract does not say how many people took part, and 8.5 fl oz (250 ml) is roughly the juice of five lemons. Energy intake three hours later did not change. Lemon juice diets worked like a plain calorie cut. In a randomized trial in 84 overweight premenopausal Korean women, a short diet of lemon juice mixed with maple and palm syrups cut weight and body fat more than no diet change, as did a calorie-matched placebo diet, and the authors put the loss down to calorie restriction. The EU refused a claim that lemon supports digestion, which means the evidence fell short at the time of review. Two small medical uses stand apart. In a 6-week crossover trial in 24 people whose urinary catheters kept blocking, lemon juice widened the margin against crust forming by 0.84 pH units (95% CI 0.63 to 1.04), more than extra fluid or potassium citrate. That is a urine measure and not a count of blockages. In 9 patients with thyroid cancer, lemon juice given to make saliva flow before radioiodine lowered the potential radiation dose to the salivary glands by 34.2% on average, in a comparison without randomization. Heartburn is the caution with evidence behind it, from the two year trial above. On teeth there is only lab data: 5 minutes of lemon juice on 25 extracted tooth roots raised dentin permeability as other acidic drinks did, and brushing afterward lowered it again. We found no data on lemon juice in pregnancy and none on interactions with medicines. All the stone trials were in people who already had stones.

Sources

1. lmj-daily-r7-01 · reference dataset
   Lemon juice, raw (FDC 167747, SR Legacy) - Vitamin C 38.7 MG - Folate 20 UG - Vitamin B-6 0.046 MG | CoFID 14-277 Lemon juice, fresh - Vitamin C 36 MG - Folate 13 UG - Vitamin B6 0.05 MG - Energy 7 KCAL - Total sugars 1.6 G
   USDA FoodData Central, SR Legacy record 167747, with UK CoFID 2021 (Public Health England, OGL v3.0) · checked 2026-09-29
2. lmj-daily-r7-02 · reference dataset
   Lemon juice, 100%, freshly squeezed (FNDDS 61204010, fdc_id 2709181) - Juice of 1 lemon (2-1/8" dia) 47 g - Juice of 1 wedge or slice 6 g - 1 fl oz (no ice) 31 g - Quantity not specified 8 g
   USDA FNDDS (FoodData Central, Survey), food code 61204010, fdc_id 2709181 · checked 2026-09-29
3. lmj-daily-r7-03 · reference dataset
   USDA-RETN-R6:270 FRUITS,CITRUS,CKD (Fruits and Fruit Juices) - folate_total_ug 70% - vitamin_c_mg 95% - thiamin_mg 95% - vitamin_b6_mg 95% - potassium_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007) · checked 2026-09-29
4. ev-lemjw-02 · meta-analysis of RCTs
   The meta-analysis showed that orange juice and/or hesperidin had no significant effect on body weight [weighted mean difference (WMD) = -0.31 kg; 95% CI, -1.44 to 0.82, P = 0.592], body mass index [WMD = 0.11 kg/m2; 95% CI, -0.33 to 0.56, P = 0.617], fat mass [WMD = 0.14 kg; 95% CI, -0.95 to 1.22, P = 0.807], percentage body fat [WMD = -0.70%; 95% CI, -2.58 to 1.18, P = 0.463] and waist circumference [WMD = 0.07 cm; 95% CI, -1.16 to 1.30, P = 0.588].
   Clin Nutr ESPEN, 2021 · checked 2026-10-07
5. ev-lemjw-05 · RCT
   None of the tested beverages had an effect on ad libitum energy intake.
   Eur J Nutr, 2021 · checked 2026-10-07
6. lmj-daily-r7-08 · randomized crossover trial
   A randomized crossover study was conducted with equal portions of bread (100 g) and 250 ml of water, black tea or lemon juice. ... Lemon juice significantly lowered the mean blood glucose concentration peak by 30% (p < 0.01) and delayed it more than 35 min (78 vs. 41 min with water, p < 0.0001). None of the tested beverages had an effect on ad libitum energy intake.
   Eur J Nutr, 2021 · checked 2026-09-29
7. ev-lemjw-07 · case-control
   There was considerable risk of erosion when citrus fruits were eaten more than twice a day (AOR 37), soft drinks were drunk daily (AOR 4), apple vinegar was ingested weekly (AOR 10), or sport drinks were drunk weekly (AOR 4).
   Journal of Dental Research, 1991, 70(6):942-7 · checked 2026-10-07
8. ev-lemjw-08 · meta-analysis of observational studies
   Meta-analyses revealed significant associations between erosive tooth wear and male gender (padj.<0.001; OR=1.30, 95 % CI: 1.16-1.44), regurgitation (padj.=0.033; OR=2.27, 95 % CI: 1.41-3.65), digestive disorders (padj.<0.001; OR=1.81, 95 % CI: 1.48-2.21), consumption of acidic foods (padj.=0.033; OR=2.40, 95 % CI: 1.44-4.00), seasoning sauces (padj.=0.003; OR=1.28, 95 % CI: 1.13-1.44), nutritional supplements (padj.=0.019; OR=1.73, 95 % CI: 1.28-2.35), and carbonated drinks (padj.=0.019; OR=1.43, 95 % CI: 1.17-1.75).
   J Dent, 2024 · checked 2026-10-07
9. ev-lemjw-09 · in vitro
   All the products showed a great erosive potential on human deciduous dental enamel.
   Caries Research, 1996, 30(5):373-8 · checked 2026-10-07
10. lmj-daily-r7-06 · randomized controlled trial
    Overall, 45 patients (22·2%) had gastrointestinal disorders: 37 (37·0%) in the lemon juice supplementation group and eight (7·8%) in the control group (p<0·001). In particular, there were 21 patients with gastric pyrosis/heartburn and eight with epigastralgia in the lemon juice supplementation group as compared to one with gastric pyrosis/heartburn (p<0·001) and three with epigastralgia (p = 0·130) in the control group.
    EClinicalMedicine, 2022 · checked 2026-09-29
11. lmj-daily-r7-07 · 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 2026-09-29
12. lmj-daily-r7-13 · in vitro study
    exposure to different acid substances for 5 min (orange, cola drink, vinegar, white wine, lemon juice) ... All acidic substances increased dentin permeability significantly after scraping (p< 0.05).
    Braz Dent J, 2010 · checked 2026-09-29
13. ev-lemjw-10 · regulatory register
    POL-HC-6937 Citrus limon (Common Name : Lemon) Helps to support the digestion contributes to the normal function of intestinal tract helps support the digestive juice flow. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6937, snapshot 2026-09-21 · checked 2026-10-07
14. lmj-daily-r7-09 · randomized controlled trial
    Changes in body weight, body mass index, percentage body fat, and waist-hip ratio were significantly greater in the Lemon-D and Positive-C groups compared to the Normal-C group. ... Therefore, we suppose that the lemon detox program reduces body fat and insulin resistance through caloric restriction
    Nutr Res, 2015 · checked 2026-09-29
15. lmj-daily-r7-10 · regulatory decision
    POL-HC-6937 Citrus limon (Common Name : Lemon) Helps to support the digestion contributes to the normal function of intestinal tract helps support the digestive juice flow. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6937, snapshot 2026-09-21 · checked 2026-09-29
16. ev-lemjw-03 · RCT
    Changes in body weight, body mass index, percentage body fat, and waist-hip ratio were significantly greater in the Lemon-D and Positive-C groups compared to the Normal-C group.
    Nutr Res, 2015 · checked 2026-10-07
17. lmj-daily-r7-04 · randomized controlled trial
    Exactly 60 mEq/day fresh lemon juice ( approximately 85 cc/day) and potassium citrate (60 mEq/day) were given to the patients of first and second group, respectively. ... There was 2.5-, 3.5- and 0.8-fold increase in urinary citrate level of lemon juice, potassium citrate and dietary recommendation groups, respectively.
    Urol Res, 2008 · checked 2026-09-29
18. lmj-daily-r7-05 · randomized controlled trial
    Over two-year follow-up 21 participants in the standard diet with fresh lemon juice supplementation group (21·0%) and 32 in the standard diet group (31·1%) had recurrent stones. ... the hazard ratio (95 percent confidence interval) of a recurrence amongst the participants in the standard diet with lemon juice supplementation group as compared with the participants in the standard diet group (Fig. 2) was 0·62 (0·35 to 1·07). This ratio was non-significant (p = 0·089).
    EClinicalMedicine, 2022 · checked 2026-09-29
19. lmj-daily-r7-11 · prospective comparative study
    A total of 2100 time points were analyzed in nine patients (18 PGs). ... Mean percentage decrease in relative PRAD was 34.2±17.4% (range, 3.1-66.1%). CONCLUSION: During the time period studied, LJ administration did not result in a 'rebound effect' but resulted in mean relative decrease of 34.2% in PRAD to the PGs.
    Nucl Med Commun, 2014 · checked 2026-09-29
20. lmj-daily-r7-12 · randomized crossover trial
    We performed a 6-week randomized crossover study in 24 patients with catheter blockage who were randomly allocated to a specific sequence of 3 consecutive available treatments, including increased fluid intake, lemon juice and potassium citrate. ... Average increase in the safety margin (nucleation pH minus voiding pH) beyond baseline was 0.84 (95% CI 0.63-1.04), 0.57 (95% CI 0.37-0.78) and 0.41 (95% CI 0.20-0.61) for lemon juice, increased fluid intake and potassium citrate, respectively.
    J Urol, 2010 · checked 2026-09-29
21. ev-lemjw-01 · meta-analysis of RCTs
    Pooled results by the random-effects model showed that citrus and/or its extracts administration significantly reduced 1.280 kg body weight (95% CI: -1.818 to -0.741, p = 0.000, I2 = 81.4%), 0.322 kg/m2 BMI (95% CI: -0.599 to -0.046, p = 0.022, I2 = 87.0%), 2.185 cm WC (95% CI: -3.804 to -0.566, p = 0.008, I2 = 98.3%), and 2.137 cm HC (95% CI: -3.775 to -0.500, p = 0.011, I2 = 96.2%), respectively, but no significantly decreased effects on WHR and body fat were observed.
    Phytother Res, 2020 · checked 2026-10-07
22. ev-lemjw-04 · RCT
    Therefore, we suppose that the lemon detox program reduces body fat and insulin resistance through caloric restriction and might have a potential beneficial effect on risk factors for cardiovascular disease related to circulating hs-CRP reduction without hematological changes.
    Nutr Res, 2015 · checked 2026-10-07
23. ev-lemjw-06 · animal study
    Additionally, LFP reduced body weight (9.7%) and fat tissue weight (25.7%) of rats; reduced serum TG (17.0%), FFA (17.9%), glucose (29.3%) and ketone body (6.8%); and increased serum HDL-C (17.6%) and lipase activity (17.8%).
    Nutrients, 2021, 13(8):2809 · checked 2026-10-07