Apple Cider Vinegar: What the Research Says, and How to Use It Safely

What apple cider vinegar is

Apple cider vinegar is vinegar made from fermented apples. Like other vinegars, its main active component is acetic acid. Harvard Health notes that acetic acid, or perhaps other compounds in the vinegar, is the likely source of whatever health effects it has.

One detail is easy to miss: many of the best-known vinegar studies didn't test apple cider vinegar specifically. Harvard Health points out that the most widely quoted human weight study used vinegar in general. Keep that in mind when you see apple cider vinegar credited with results from vinegar research.

Blood sugar after meals: the strongest evidence

The most consistent finding is about blood sugar after eating. A 2017 meta-analysis of clinical trials found that people who had vinegar with a meal had smaller rises in blood sugar and insulin afterward than people who didn't. Harvard Health explains that vinegar might help prevent blood sugar spikes in people with prediabetes and type 2 diabetes, perhaps by blocking starch absorption.

Longer studies have looked at daily use. A 2025 meta-analysis of seven controlled trials in people with type 2 diabetes reported lower fasting blood sugar and HbA1c with apple cider vinegar. The trials were small, though, and apple cider vinegar is not a substitute for diabetes medication, diet or exercise.

One group should be especially careful. In a small study of 10 people with type 1 diabetes and gastroparesis, a condition in which the stomach already empties slowly, apple cider vinegar slowed stomach emptying even further. The researchers noted this could be a disadvantage for blood sugar control.

Weight loss: modest at best

The weight-loss evidence is thinner. The most widely quoted human study is a 12-week trial in Japan in which 175 adults with obesity drank a beverage containing 0, 1 or 2 tablespoons of vinegar each day. Both vinegar groups ended with lower body weight, waist size and triglycerides than the placebo group. Harvard Health describes the weight loss as modest, about 2 to 4 pounds over three months. The researchers worked at a corporate research institute rather than a university, which is worth knowing.

Harvard Health also describes a 2018 trial of 39 people on a reduced-calorie diet in which those who added apple cider vinegar lost more weight over 12 weeks, though both groups lost weight. Its overall verdict is blunt: the evidence that vinegar is a reliable, long-term way to lose excess weight is not compelling.

There's another reason for caution. A 2024 trial of 120 young people in Lebanon with overweight or obesity reported reductions in weight, blood sugar and blood fats with daily apple cider vinegar. In 2025, the journal retracted it. If you saw headlines about that study, its findings shouldn't be relied on.

How people use it, and how much

There is no official dose. Harvard Health notes that recommendations vary but are mostly on the order of 1 to 2 teaspoons before or with meals. The Japanese weight study used more: 1 or 2 tablespoons (15 or 30 milliliters) a day, mixed into a 500-milliliter drink. If you want to try it, these are the gentlest approaches:

• Use it in food. Harvard Health suggests a vinaigrette as a better way to get vinegar than sipping it straight, and a splash in a marinade or slaw works too.
• Always dilute it if you drink it. Mix a teaspoon or two into a large glass of water, and never drink it undiluted.
• Have it with a meal. The blood sugar studies looked at vinegar taken with food.
• Start small, and stop if it gives you heartburn, nausea or throat discomfort.
• Skip vinegar tablets. Lab testing of eight apple cider vinegar tablet products found wide differences in tablet size, acidity and acid content, and raised doubt about whether apple cider vinegar was really in them. The testing followed a reported esophageal injury from a tablet.

Protect your teeth

Vinegar is acidic, and acid can wear away tooth enamel. In a lab study, slices of human enamel soaked in several kinds of vinegar lost minerals, with losses of around 20% near the surface for some vinegars after a few hours. That's not the same as drinking a diluted glass, and the authors cautioned against applying lab results directly to real mouths. The American Dental Association notes some evidence that heavy use of vinegar-based dressings may increase erosion, though it calls that evidence limited.

The ADA's general advice for acidic drinks applies here:

• Don't swish it around or hold it in your mouth.
• Drink it through a straw positioned behind your front teeth.
• Rinse your mouth with water afterward.
• Don't brush right away. The ADA suggests rinsing with water rather than brushing immediately after acidic drinks.

Who should talk to a doctor first

Apple cider vinegar is a common food ingredient, but drinking it daily isn't right for everyone. Check with your doctor or pharmacist before starting if any of these apply:

• You take insulin or other medicines that lower blood sugar. Harvard Health cautions that vinegar can alter insulin levels and that people with diabetes should be particularly careful.
• You take diuretics or other medicines that can lower potassium, or you've had low potassium. Harvard Health notes that vinegar has been reported to cause or worsen low potassium, and one published case described low potassium and osteoporosis in a patient who drank large amounts of cider vinegar.
• You have gastroparesis, since vinegar can slow stomach emptying further.
• You have trouble swallowing or a history of throat or esophageal problems.

The bottom line

Apple cider vinegar is a useful ingredient and a reasonable small habit for people who enjoy it. The best evidence is for a modest drop in blood sugar after meals, and the evidence for weight loss is weak. Use it in food or well diluted, protect your teeth, skip the tablets, and talk to your doctor first if you have diabetes, gastroparesis or low potassium, or take medicines that affect blood sugar or potassium.

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