Apple cider vinegar

Updated October 2026 · 7 min read

What it is, and its place in classical medicine

Apple cider vinegar is apple juice that has been fermented twice, first into alcohol and then into acetic acid. Acetic acid, about 5% of the bottle, is the ingredient researchers study.

Vinegar (الخل) was a staple of the Islamic kitchen and pharmacy. Ibn Sina and Ibn al-Baytar list it in their works on foods and drugs, and physicians used it to stimulate appetite and digestion and to preserve food. It was also the base of sikanjabin, the classic vinegar and honey syrup drink. These authors write about vinegar in general, not apple cider vinegar by name. Apple cider vinegar is simply the version most people can buy today.

What the research shows

• Blood sugar after meals: this is the best-supported benefit. Several small trials found that vinegar taken with or just before a carbohydrate-heavy meal lowers the blood sugar and insulin spike afterwards, modestly.
• Weight: small trials report a loss of a few kilograms at most over about 3 months, probably because people feel fuller. It is not a fat-burning shortcut.
• Cholesterol and blood pressure: results are small and inconsistent. Do not rely on it.

Does it help with heartburn?

There is no good evidence that it does, and for many people it makes heartburn worse. The popular idea is that heartburn comes from too little stomach acid and that vinegar fixes this. Reflux is mostly caused by the valve at the top of the stomach letting acid up, and no trial shows that vinegar helps it. Vinegar is itself acidic and can irritate an already sore throat or oesophagus. It can also slow how fast the stomach empties, which can make reflux and fullness worse.

If vinegar seems to help you, that may be coincidence or the effect of a big glass of water. If it makes you worse, stop. See a doctor if you get heartburn more than twice a week, because ongoing reflux can damage the oesophagus.

With every meal?

We don't recommend it. The trials that found a benefit used about 1 to 2 tablespoons (15 to 30 ml) a day in a large glass of water, often once before the biggest carbohydrate meal. Nobody has shown that more is better, and three doses a day makes the downsides more likely: worn tooth enamel, an irritated throat and stomach, and, in a reported case of heavy long-term use, low potassium and weakened bones.

Who should avoid it or ask a doctor first

• acid reflux, stomach ulcers or gastritis
• slow stomach emptying (gastroparesis), which is common in long-standing diabetes
• insulin or other diabetes drugs, because it can push blood sugar too low
• diuretics or digoxin, and kidney disease, because of the potassium effect
• sensitive or weak teeth
• pregnancy, and children

In Ramadan, vinegar belongs in the suhoor or iftar meal, diluted, and not as a drink on an empty stomach.