Apple cider vinegar: what the research does and doesn't show

The evidence doesn't support apple cider vinegar as a treatment for bloating, constipation, diarrhea, or spot-reducing belly fat, and no study has tested it for safety in pregnancy or breastfeeding. A small trial did find that vinegar slows stomach emptying, which may explain why some people feel fuller or gassier after taking it — a mechanism, not a benefit.

What the evidence doesn't support

No trial supports apple cider vinegar for relieving bloating, constipation or diarrhea, for burning or reducing belly fat specifically, or for use during pregnancy or while breastfeeding, where no research exists at all. Gummy versions haven't been tested in any of the trials below, which all used a measured liquid vinegar.

What the trials found

A 12-week, placebo-controlled trial in obese Japanese adults gave participants a daily drink with 750 mg or 1,500 mg of acetic acid (15 or 30 mL of vinegar) or a vinegar-free placebo drink. Both vinegar groups ended the trial with lower body weight, waist size and triglycerides than the placebo group — doses well above what a typical vinegar capsule provides, and from one research group's trial, not a body of confirming evidence.

A meta-analysis pooling multiple small, mostly single-meal trials found that vinegar taken with a meal was linked to a smaller rise in blood sugar and insulin afterward than not taking it. The pooled trials were short and varied in dose, and the analysis doesn't address weight loss directly, only the after-meal blood sugar response.

A small 2007 pilot trial in 10 people with type 1 diabetes and pre-existing diabetic gastroparesis (delayed stomach emptying) measured how fast their stomachs emptied a meal, with and without 30 mL of apple cider vinegar taken daily beforehand. Vinegar slowed the gastric emptying rate further than the meal alone — a median of 17% emptied versus 27% without vinegar — which the researchers described as a disadvantage for blood sugar control in that population. For someone without gastroparesis, slower gastric emptying could plausibly show up as a feeling of fullness or bloating, though this trial didn't measure that directly and was conducted in people who already had a stomach-emptying disorder.

A systematic review of apple vinegar's safety in 13 human and 12 animal studies found the risk of side effects at recommended amounts appears low, and identified mild gastrointestinal upset as the most commonly reported issue — consistent with both bloating and, in some people, looser stools. No study in that review isolated diarrhea or constipation as its own measured outcome, and none tested apple cider vinegar in pregnant or breastfeeding people.

No study identified in this search tested an apple cider vinegar gummy product specifically. Gummies are manufactured differently from a liquid or a capsule, and we haven't verified how much acetic acid, if any, a given gummy product retains through that process — a question for that product's own label, not something this research answers.

Questions people ask

Does apple cider vinegar help with bloating or gas?

No trial found that apple cider vinegar relieves bloating or gas. The pilot study above actually found it slows stomach emptying in people with a pre-existing emptying disorder, which points toward more fullness, not less.

Does apple cider vinegar help with constipation?

No trial has tested apple cider vinegar as a treatment for constipation. It isn't a documented laxative in any study we found.

Can apple cider vinegar cause diarrhea or constipation?

A general safety review found gastrointestinal upset is the most commonly reported side effect of apple vinegar at typical intakes, without breaking that down into diarrhea versus constipation specifically. Either is possible for some people; neither is the norm reported in the reviewed studies.

Does apple cider vinegar help you lose belly fat?

One 12-week trial linked daily vinegar drinks to a smaller waist size than a placebo drink, at doses of 750–1,500 mg of acetic acid a day — well above a typical capsule serving, and from a single research group. It didn't isolate belly fat from overall weight loss.

Is apple cider vinegar safe during pregnancy or breastfeeding?

No study has tested apple cider vinegar in pregnant or breastfeeding people, so there's no dose or safety data specific to either situation. That's a question for a doctor, not this article.

Are apple cider vinegar gummies good for you?

No study identified tested a gummy product specifically. Every trial referenced on this page used a measured liquid vinegar, so none of these findings can be assumed to carry over to a gummy.

Why does apple cider vinegar help gallbladder pain?

No study we found tested apple cider vinegar for gallbladder pain. Gallbladder pain can signal a condition, like gallstones, that needs medical evaluation rather than a home remedy.

How do you apply apple cider vinegar for knee pain?

No study identified tested topical apple cider vinegar for joint pain. Undiluted vinegar is acidic enough to irritate skin on contact, which is a documented risk in the safety literature, not a documented benefit for a joint.

When to talk to a doctor

Bloating, constipation or diarrhea that's persistent, gallbladder pain, joint pain that isn't improving, or any use during pregnancy or breastfeeding are all reasons to talk to a doctor rather than experiment with apple cider vinegar, which isn't a treatment for any of them.

Related reading: apple cider vinegar benefits: what the research does and doesn't show, apple cider vinegar side effects, and how much apple cider vinegar should you take a day.