Benefits
Post-meal blood sugar and insulin response
In 12 healthy adults, vinegar served with white bread lowered the early rise in blood glucose and insulin, with larger effects at higher acetic acid doses. In a small single-meal study, vinegar before a high-carbohydrate meal improved insulin sensitivity in people with insulin resistance; the smaller change in people with type 2 diabetes was not statistically significant.
Weight management
In a 12-week double-blind trial in 175 Japanese adults with BMI 25 to 30, drinking 15 or 30 mL of apple vinegar a day lowered body weight (about 1 to 2 kg), BMI, waist size and visceral fat versus placebo; a vinegar maker ran the trial. Most of the weight came back within four weeks of stopping. A 2026 umbrella review of meta-analyses, which left out a retracted trial, put the average weight change at about 1 kg, with no significant change in BMI or waist size.
Fasting glucose and total cholesterol
A meta-analysis of 9 trials found ACV lowered fasting glucose by about 8 mg/dL and total cholesterol by about 6 mg/dL, with high variation between trials for glucose and HbA1c. LDL, HDL and fasting insulin did not change, and fasting glucose appeared to rise in healthy participants. Triglycerides fell in some subgroups.
Fullness after a meal
In the same 12-person bread meal study, fullness ratings rose in step with the amount of acetic acid, and the highest vinegar dose increased fullness at 30, 90 and 120 minutes after eating. This was a single-meal test, so it does not show whether the effect lasts with daily use.
Mechanism of action
Slower stomach emptying
In 10 people with type 1 diabetes and slow stomach emptying (gastroparesis), 30 mL of apple cider vinegar taken with a rice pudding meal slowed gastric emptying further. Slower emptying delays the arrival of carbohydrate in the small intestine, which fits the lower early glucose peak seen after vinegar meals.
Acetic acid dose response
In a bread meal study, higher acetic acid levels gave lower 30-minute glucose and insulin responses and higher fullness ratings, pointing to acetic acid as the active component. Trials therefore dose vinegar by its acetic acid content, such as 750 or 1,500 mg a day.
Clinical trials
Placebo-controlled crossover meal test: a drink of 20 g vinegar in 40 g water, or placebo, taken just before a high-carbohydrate meal (87 g carbohydrate). Results as summarized in the first author's later review. (Johnston et al. 2004, Diabetes Care)
29 adults: 8 insulin-sensitive controls, 11 with insulin resistance and 10 with type 2 diabetes.
In the 11 people with insulin resistance, vinegar lowered post-meal blood glucose by 64% and improved insulin sensitivity after the meal by 34% versus placebo. In the 10 people with type 2 diabetes, the 17% drop in post-meal glucose and the 19% gain in insulin sensitivity were not statistically significant. This was a single-meal test, so it shows an acute effect only.
Double-blind, placebo-controlled, parallel-group trial: 500 mL a day of a drink containing 15 mL apple vinegar (750 mg acetic acid), 30 mL (1,500 mg) or none, for 12 weeks. (Kondo et al. 2009, Biosci Biotechnol Biochem)
175 Japanese adults with BMI 25 to 30 randomized; 155 completed the study.
Both vinegar doses lowered body weight, BMI, body fat ratio, waist and hip size, visceral fat area and serum triglycerides versus placebo; weight fell by about 1 to 2 kg. The higher dose beat the lower dose for weight and BMI. Diet and step counts did not differ between groups. The study was led by researchers at the Mizkan vinegar company.