When to Take Apple Cider Vinegar: Morning or Night?

Take apple cider vinegar with a meal that contains carbohydrate, diluted in water. In three of four small crossover trials, vinegar with a bagel-and-juice meal cut the blood-sugar rise by about 20%, and it worked better at the meal than 5 hours before it¹. We found no trial showing that a morning, empty-stomach or bedtime dose works better.

One caveat: most meal-timing trials tested vinegar in general, not apple cider vinegar specifically. The apple-cider-specific evidence comes mainly from longer trials and reviews. For what the vinegar does and does not do, and for dosing and safety, see our apple cider vinegar page.

Take it with the meal or at the start of it. In four randomized crossover trials of 9-10 adults each, 2 teaspoons (10 g) of vinegar lowered the blood-sugar rise after a bagel-and-juice meal in three of them. The effect was largest when the vinegar was taken during the meal rather than 5 hours before it¹.

A 2017 meta-analysis of clinical trials found that vinegar with a meal lowered the blood-sugar response (standardized mean difference -0.60, 95% CI -1.08 to -0.11) and the insulin response (-1.30, 95% CI -1.98 to -0.62). Its abstract does not compare times of day².

Two details limit that result. In the fourth Johnston trial, vinegar did not change the glucose response to a pure dextrose drink, so it seems to act on carbohydrate digestion¹. And in 16 adults with type 2 diabetes, split into two groups, vinegar lowered the response to a high-glycemic-index meal of mashed potatoes and milk but not to a low-glycemic-index meal of whole-grain bread, lettuce and cheese³. A letter reporting a randomized trial in type 2 diabetes found that vinegar with an oral glucose load did not improve glucose tolerance, which fits the same pattern⁴.

The likely mechanism is slower stomach emptying. In 10 healthy volunteers, vinegar with a starchy meal lowered the glucose and insulin responses and lowered paracetamol levels, a marker of how fast the stomach empties⁵. A crossover trial in 12 healthy adults found a dose-response: the more acetic acid in a bread meal, the smaller the glucose response and the higher the fullness ratings⁶.

Longer-term results in type 2 diabetes are separate from timing. A 2025 meta-analysis of 7 controlled trials of apple cider vinegar found lower fasting glucose (-21.9 mg/dL, 95% CI -29.19 to -14.67) and HbA1c (-1.53, 95% CI -2.65 to -0.41)⁷. A 2020 meta-analysis of 6 studies of vinegar in 317 patients also found better fasting glucose and HbA1c, but its authors warned that the studies were small and the vinegar varied⁸. Neither abstract reports a comparison of times of day.

For the full picture, see our pages on apple cider vinegar for post-meal glucose control and insulin sensitivity, and our diabetes guide.

How long should you wait to eat after taking it? No trial tested a waiting period. The studies that showed an effect gave the vinegar with the meal or at the start of it^{1, 9}. We found no trial that gave it after eating. There is nothing in the evidence to wait for.

Neither has strong support. We found no trial that compared morning with evening dosing in any group.

Bedtime has one pilot study. A 2007 controlled trial in adults with well-controlled type 2 diabetes tested whether vinegar at bedtime lowers next-morning fasting glucose, and its title reports that it moderated waking glucose¹⁰. The full paper is paywalled, so we read only its title and partial abstract, not its size or effect. A pilot in people with diabetes cannot show a benefit for healthy sleepers.

The popular morning shot has no trial behind it either. The benefit trials measured, a smaller blood-sugar rise, attaches to a meal rather than to a time of day¹. If your starchy or high-glycemic meal is in the evening, take it then. If it is breakfast, take it at breakfast³.

You get no tested benefit from the empty stomach, and the evidence points the other way for blood sugar. The one trial that compared timing found the glucose effect was weaker when vinegar was taken 5 hours before a meal than during it¹.

Vinegar can also upset the stomach, though no trial tested this on an empty stomach. In one feeding study of 16 healthy adults, vinegar taken with breakfast reduced appetite, but nausea ratings rose too. The authors concluded the effect was largely due to poor tolerability after swallowing, not a true satiety signal. A taste-only study of 14 adults showed no appetite effect¹¹.

In the trials that report how it was given, the vinegar was diluted in water^{12, 9}. A case report describes erosive tooth wear in a 15-year-old girl, traced to a daily glass of apple cider vinegar; the report does not say how it was diluted¹³.

We found no trial that tested timing for weight loss, and the evidence that the vinegar helps at all is modest. A 2025 meta-analysis of 10 randomized trials in 789 adults found that daily vinegar lowered body weight (standardized mean difference -0.39, 95% CI -0.63 to -0.15), BMI (-0.65) and waist circumference (-0.34), with high heterogeneity (I² 62%, 83% and 61%)¹⁴. The effects appeared for up to 12 weeks, in adults who were overweight, obese or had type 2 diabetes. Other body-composition measures did not change significantly.

Treat those numbers with caution. A 2024 placebo-controlled trial in 120 overweight young people was later retracted^{15, 16}. We could not tell from the meta-analysis abstract whether it counted that trial. Part of vinegar's appetite effect may be nausea, as above¹¹.

If weight is your goal, pick a time you will keep. Our weight loss support page covers what else has evidence.

We found no evidence on when, or whether, to take it for reflux. A 2019 review of popular remedies for esophageal symptoms listed apple cider vinegar among them and concluded that a substantial gap persists between anecdote and empirical evidence for most such remedies¹⁷.

Reflux means acid is already irritating the esophagus, and vinegar is an acid. Apple cider vinegar tablets have caused esophageal injury in a case report¹⁸. That is an inference rather than a trial result, but it is reason to talk to a clinician before trying vinegar for heartburn. Our pages on heartburn and acid reflux and GERD cover options with better support, and digestive health gathers the rest.

For tablets, the one trial we found gives no reason to expect a benefit from whole tablets. In a four-arm crossover trial in 12 young healthy adults, liquid vinegar at the start of a meal with 64 g of carbohydrate cut the 60-minute glucose rise by 31% compared with water or whole tablets. Four commercial vinegar tablets supplying 1.50 g of acetic acid, against 1.25 g in the liquid, did not⁹.

Product quality varies. The authors of a tablet-injury report tested eight apple cider vinegar tablet products, which differed widely in tablet size, pH and acid content, and they doubted that apple cider vinegar was an ingredient in the products they tested¹⁸. Memorial Sloan Kettering, summarizing the same report, says analysis of the injured 48-year-old woman's tablets revealed a high concentration of apple cider vinegar¹⁹.

We found no controlled trial of gummies or capsules, so there is no evidence-based timing for them. Memorial Sloan Kettering lists gummies, capsules and tablets as the supplement forms and advises talking to a healthcare provider before taking them¹⁹.

A systematic review of 13 human studies judged the risk of side effects inconsiderable when vinegar is taken in recommended quantities and ways. It also called the evidence for health effects insufficient²⁰. The harms that are documented come from case reports:

• Tablets and a daily glass: esophageal injury from tablets¹⁸, and tooth erosion from a daily glass, with dilution not reported¹³.
• Raw or home-fermented vinegar: Memorial Sloan Kettering advises avoiding it, because unpasteurized apple products have been implicated in E. coli and Cryptosporidium outbreaks¹⁹.
• Very large daily amounts: a case report in a 28-year-old woman describes low potassium, high renin and osteoporosis after drinking large amounts^{21, 19}.
• Liver and pancreas: a 60-year-old man with a long history of vinegar use had liver injury that improved after he stopped²². An 84-year-old woman developed pancreatitis linked to a weight-loss supplement containing apple cider vinegar¹⁹. Both are rare case reports.

On medicines and other supplements: Memorial Sloan Kettering lists no known herb-drug interactions for apple cider vinegar¹⁹, and we found no interaction trials, including with other supplements. Two facts still justify a question to your pharmacist if you take medicine that lowers blood sugar or potassium. Vinegar lowers the blood-sugar rise after meals², and a case report tied large amounts to low potassium²¹. That is an inference, not a documented interaction.

People with type 1 diabetes and gastroparesis (slow stomach emptying) should ask their care team first. In a crossover trial of 10 patients, 2 weeks of daily vinegar before breakfast slowed gastric emptying further, from a median of 27% to 17% (p < 0.05). The authors noted this might be a disadvantage for glycemic control¹². The trial did not study other kinds of diabetic gastroparesis, so applying it more widely is a guess.

Anyone with reflux, a damaged esophagus or dental erosion has a reason to avoid acid sipped between meals, for the reasons above. We found no trials in pregnancy or in children, so there is no timing guidance for either group; ask a clinician before using it.

Kidneys are a common worry, but the evidence is thin. In a 2026 randomized crossover trial, 20 adults who had never had kidney stones were assigned to two of four drinks, and only 6 took apple cider vinegar. A week of daily vinegar did not significantly change their 24-hour urine volume, pH or citrate. Coconut water raised urinary citrate by 273.8 mg/24 h and lemon water by 167.7 mg/24 h²³. The trial measured urine chemistry, not kidney function, and we found no trial that did.

• For blood sugar: take it diluted, with a starchy or high-glycemic meal. That is where the effect was seen³.
• For weight: choose any consistent time. Expect a small effect at most¹⁴.
• For reflux: do not self-treat with vinegar. See a clinician first.
• If you prefer tablets: do not expect the liquid's effect⁹. For gummies there is no timing evidence.
• If you use diabetes medicine or have gastroparesis: check with your care team before starting.

For amounts, forms and the full safety profile, see our apple cider vinegar page.

Supplements in this guide

• Apple Cider Vinegar

Related health goals

• Post-Meal Glucose Control
• Insulin Sensitivity
• Weight Loss Support

We searched a research-paper index covering PubMed with several framings: timing relative to meals, bedtime and morning dosing, weight, reflux, tablets and gummies, medicine interactions and harms. We read the records of 22 journal papers, and a Memorial Sloan Kettering monograph on 2 November 2026. We prioritised systematic reviews and randomized trials in adults, and used case reports only for harms.

What the evidence cannot tell us: we found no trial comparing morning with night, the bedtime trial was paywalled so we read only its title and partial abstract, most meal-timing trials tested vinegar in general rather than apple cider vinegar, most trials are small and short, and we found no trials of gummies or in pregnancy and children.

1. Johnston CS, et al. Examination of the antiglycemic properties of vinegar in healthy adults. Ann Nutr Metab. 2010;56(1):74-9. doi:10.1159/000272133
2. Shishehbor F, et al. Vinegar consumption can attenuate postprandial glucose and insulin responses; a systematic review and meta-analysis of clinical trials. Diabetes Res Clin Pract. 2017;127:1-9. doi:10.1016/j.diabres.2017.01.021 Our study summary.
3. Liatis S, et al. Vinegar reduces postprandial hyperglycaemia in patients with type II diabetes when added to a high, but not to a low, glycaemic index meal. Eur J Clin Nutr. 2010;64(7):727-32. doi:10.1038/ejcn.2010.89
4. van Dijk JW, et al. Vinegar co-ingestion does not improve oral glucose tolerance in patients with type 2 diabetes. J Diabetes Complications. 2012;26(5):460-1. doi:10.1016/j.jdiacomp.2012.05.009
5. Liljeberg H, et al. Delayed gastric emptying rate may explain improved glycaemia in healthy subjects to a starchy meal with added vinegar. Eur J Clin Nutr. 1998;52(5):368-71. doi:10.1038/sj.ejcn.1600572
6. Ostman E, et al. Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects. Eur J Clin Nutr. 2005;59(9):983-8. doi:10.1038/sj.ejcn.1602197
7. Arjmandfard D, et al. Effects of apple cider vinegar on glycemic control and insulin sensitivity in patients with type 2 diabetes: A GRADE-assessed systematic review and dose-response meta-analysis of controlled clinical trials. Front Nutr. 2025;12:1528383. doi:10.3389/fnut.2025.1528383 Our study summary.
8. Cheng LJ, et al. A systematic review and meta-analysis: Vinegar consumption on glycaemic control in adults with type 2 diabetes mellitus. J Adv Nurs. 2020;76(2):459-474. doi:10.1111/jan.14255 Our study summary.
9. Feise NK, et al. Commercial Vinegar Tablets Do Not Display the Same Physiological Benefits for Managing Postprandial Glucose Concentrations as Liquid Vinegar. J Nutr Metab. 2020;2020:9098739. doi:10.1155/2020/9098739
10. White AM, et al. Vinegar ingestion at bedtime moderates waking glucose concentrations in adults with well-controlled type 2 diabetes. Diabetes Care. 2007;30(11):2814-5. doi:10.2337/dc07-1062
11. Darzi J, et al. Influence of the tolerability of vinegar as an oral source of short-chain fatty acids on appetite control and food intake. Int J Obes (Lond). 2014;38(5):675-81. doi:10.1038/ijo.2013.157
12. Hlebowicz J, et al. Effect of apple cider vinegar on delayed gastric emptying in patients with type 1 diabetes mellitus: a pilot study. BMC Gastroenterol. 2007;7:46. doi:10.1186/1471-230X-7-46
13. Gambon DL, et al. [Unhealthy weight loss. Erosion by apple cider vinegar]. Ned Tijdschr Tandheelkd. 2012;119(12):589-91. doi:10.5177/ntvt.2012.12.12192
14. Castagna A, et al. Effect of Apple Cider Vinegar Intake on Body Composition in Humans with Type 2 Diabetes and/or Overweight: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. 2025;17(18). doi:10.3390/nu17183000 Our study summary.
15. Abou-Khalil R, et al. Apple cider vinegar for weight management in Lebanese adolescents and young adults with overweight and obesity: a randomised, double-blind, placebo-controlled study. BMJ Nutr Prev Health. 2024;7(1):61-67. doi:10.1136/bmjnph-2023-000823
16. Anonymous. Retraction: Apple cider vinegar for weight management in lebanese adolescents and young adults with overweight and obesity: a randomised, double-blind, placebo-controlled study. BMJ Nutr Prev Health. 2025;8(2):693. doi:10.1136/bmjnph-2023-000823ret
17. Ahuja A, et al. Popular Remedies for Esophageal Symptoms: a Critical Appraisal. Curr Gastroenterol Rep. 2019;21(8):39. doi:10.1007/s11894-019-0707-4
18. Hill LL, et al. Esophageal injury by apple cider vinegar tablets and subsequent evaluation of products. J Am Diet Assoc. 2005;105(7):1141-4. doi:10.1016/j.jada.2005.04.003
19. Memorial Sloan Kettering Cancer Center. Apple Cider Vinegar: Purported Benefits, Side Effects & More (About Herbs). https://www.mskcc.org/cancer-care/integrative-medicine/herbs/apple-cider-vinegar
20. Launholt TL, et al. Safety and side effects of apple vinegar intake and its effect on metabolic parameters and body weight: a systematic review. Eur J Nutr. 2020;59(6):2273-2289. doi:10.1007/s00394-020-02214-3
21. Lhotta K, et al. Hypokalemia, hyperreninemia and osteoporosis in a patient ingesting large amounts of cider vinegar. Nephron. 1998;80(2):242-3. doi:10.1159/000045180
22. Andonie CR, et al. Apple Cider Vinegar-Induced Hepatotoxicity: A Rare Case Report. Oxf Med Case Reports. 2025;2025(7):omaf097. doi:10.1093/omcr/omaf097
23. Baker B, et al. Apple cider vinegar for prevention of urinary lithiasis (APUL): a randomized crossover trial. Int Urol Nephrol. 2026;58(6):1989-1994. doi:10.1007/s11255-025-04944-x Our study summary.