Apple cider vinegar does not appear to increase your resting metabolic rate in any meaningful way. A randomized, double-blind crossover study of 16 healthy adults found that four days of apple cider vinegar supplementation (30 mL per day) produced no significant change in resting energy expenditure compared to a placebo. The effect size was essentially zero (0.06), meaning the difference between groups was negligible. The same held true during exercise: energy expenditure at two different cycling intensities was virtually identical whether participants took vinegar or not.
So where does the idea come from, and is there anything real behind it? The answer is more nuanced than the headline suggests.
What Acetic Acid Does Inside Cells
Apple cider vinegar is roughly 4 to 8 percent acetic acid, which is the compound responsible for most of its proposed metabolic effects. When acetic acid enters your cells, it gets converted into a molecule called acetyl-CoA. That conversion process generates a byproduct that activates an enzyme known as AMPK, sometimes called the body’s “energy sensor.” AMPK plays a central role in regulating how your body balances energy: when it switches on, it promotes fat burning and blocks fat production.
In muscle cell studies, acetic acid increased AMPK activity, which in turn improved glucose uptake and shifted the cells toward burning fatty acids for fuel instead of storing them. In animal liver tissue, acetic acid also turned up the activity of genes involved in fat breakdown and heat generation. These are real biochemical effects, and they sound impressive on paper. The problem is that what happens in isolated cells and rodent livers doesn’t always translate into a noticeable change in how many calories a living, breathing human burns in a day.
Why It Doesn’t Change Your Calorie Burn
The gap between cellular mechanisms and whole-body metabolism is significant. Your resting metabolic rate is driven primarily by your body composition (how much muscle and organ tissue you have), your age, and your hormonal environment. The amount of acetic acid in a tablespoon or two of vinegar is small relative to the enormous metabolic machinery running your body around the clock. Activating AMPK in some muscle cells is a far cry from revving up total energy expenditure by a detectable amount.
The crossover study mentioned above measured this directly. Participants consuming apple cider vinegar burned about 1,669 calories per day at rest, compared to 1,654 on the placebo. That 15-calorie difference was not statistically significant and falls well within normal day-to-day variation. During exercise, vinegar users actually burned slightly fewer calories than the placebo group at both low and moderate intensities, though again the differences were too small to mean anything.
The Weight Loss Study That Was Retracted
You may have seen headlines about a 2024 study claiming that apple cider vinegar caused 6 to 8 kilograms (roughly 13 to 18 pounds) of weight loss over 12 weeks in overweight young adults. That study, published in BMJ Nutrition, Prevention & Health, tested daily doses of 5, 10, and 15 mL of vinegar diluted in water. The results were striking enough to go viral.
The BMJ Group retracted the study in 2025. Independent experts identified major problems, including implausible statistical values, unreliable raw data, inadequate reporting of methods, and the absence of prospective trial registration. The journal’s ethics editor stated explicitly that “the results of the study are unreliable” and that journalists and others should no longer reference or use them. This is worth knowing because the study still circulates widely on social media and wellness websites as though it were valid evidence.
What Apple Cider Vinegar Might Actually Do
If the metabolism-boosting claim falls flat, there are a couple of other ways vinegar could theoretically influence weight, though neither is dramatic.
First, vinegar slows down gastric emptying, which is the rate at which food leaves your stomach. In a study of patients with type 1 diabetes, a meal consumed with 30 mL of apple cider vinegar had a gastric emptying rate of 17 percent compared to 27 percent without vinegar. Slower emptying can make you feel full longer, potentially leading you to eat less at subsequent meals. However, this same effect is a concern for people who already have slow stomach emptying (gastroparesis), because vinegar can make the problem worse.
Second, some smaller studies in Japanese adults found modest weight and triglyceride reductions with daily vinegar consumption over 12 weeks, though the losses were much smaller than the retracted study claimed, and the participants were often also following calorie-restricted diets. It’s difficult to separate the vinegar’s contribution from the diet itself.
Typical Amounts Used in Studies
Most research has used between 5 and 30 mL of apple cider vinegar per day (roughly one teaspoon to two tablespoons), diluted in a full glass of water and consumed on an empty stomach in the morning. The vinegar used typically contains about 5 percent acetic acid. Higher doses have not been shown to produce proportionally greater effects, and undiluted vinegar can damage tooth enamel and irritate the esophagus.
If you choose to try it, dilution matters. Drinking it straight is harsh on your throat and teeth, and there’s no evidence that a more concentrated dose does anything extra. Some people mix it into salad dressings or add it to meals, which is a gentler approach and aligns with how vinegar has been consumed for centuries without any special metabolic claims attached.
The Bottom Line on Metabolism
Apple cider vinegar activates a real metabolic enzyme in cell and animal studies, but that activation does not translate into a measurable increase in how many calories you burn at rest or during exercise. The most widely cited weight loss trial has been retracted for serious data problems. The most plausible benefit is a modest effect on fullness through slower digestion, which is a far less exciting mechanism than “boosting metabolism” but at least has some surviving evidence behind it. For anyone looking to meaningfully increase their metabolic rate, building muscle through resistance training and staying physically active remain the most reliable approaches.