Apple Cider Vinegar Benefits: One Is Real, One Was Retracted

Something real is in here.

It is smaller than advertised, it is not the benefit printed on the gummy bottle, and the single most-quoted study behind the weight-loss claim no longer exists.

That last part is not a turn of phrase. In September 2025 the journal pulled it. Most of the internet has not noticed.

The trial behind the headlines was retracted

In March 2024, BMJ Nutrition, Prevention & Health published a randomised, double-blind, placebo-controlled trial of apple cider vinegar in 120 overweight and obese people in Lebanon. Twelve weeks. Weight down, blood glucose down, triglycerides down, cholesterol down. The paper concluded that apple cider vinegar “could be a promising antiobesity supplement that does not produce any side effects.” [2]

It went everywhere. If you read anything about apple cider vinegar between 2024 and now, you read something downstream of that trial.

On 23 September 2025 the journal retracted it. [1]

The retraction notice is public, and it is specific. On what prompted the review: “Wide ranging concerns were raised about the quality of the work after publication, including the approach to statistical analysis of the dataset; implausible values; concern about the reliability of the underlying dataset; inadequate reporting of the work; and absence of prospective trial registration.”

And on the decision itself: “The paper is being retracted because the authors’ analyses could not be replicated and multiple errors were identified. The authors supplied dataset also demonstrated patterns inconsistent with random allocation of participants to treatment groups, improbably small p-values given the limited number of participants included in the study.”

Two of those phrases do real work, so here is what they mean. Patterns inconsistent with random allocation — when you split people into groups at random, the groups come out slightly lumpy, the way coin flips do. Data that looks too tidy is a sign that something other than chance did the arranging. Improbably small p-values — a p-value is roughly how surprised you should be by a result if nothing were really happening. Very small ones are hard to produce from 120 people. Several of them is harder still.

The authors’ response is in the notice too, and it belongs here: they say the discrepancies were “honest mistakes that arose from version mismatches, data rounding or formatting differences when exporting from statistical software to reporting spreadsheets.” They agreed with the decision to retract, and the notice records that they were upfront about the missing trial registration. The paper was withdrawn with their agreement, not over their objection.

So that is one study, corrected. The system worked. Why is this still the most interesting thing on the page?

Because a retraction does not reach backwards

Four days before the retraction — on 19 September 2025 — a systematic review and meta-analysis appeared in Nutrients. It pooled ten randomised trials of apple cider vinegar and body composition, 789 participants in total, and concluded that daily intake significantly reduced body weight, BMI and waist circumference. [3]

The retracted trial is in it. Reference 44.

And it is not a bit player. The review singles it out by name as one of only four trials that “reported a significant reduction in both in body weight and BMI and in metabolic parameters.”

Nobody did anything wrong. The review’s literature search closed in March 2025 and the paper went to press four days before the journal acted. That is just the calendar.

What happens next is the problem. We checked on 3 August 2026 — ten months after the retraction. The meta-analysis carries no correction, no editor’s note, and no flag of any kind, in either PubMed’s corrections record or Crossref’s. PubMed correctly labels the original trial a Retracted Publication. The meta-analysis that pooled it is still labelled a systematic review and meta-analysis, as though nothing had happened.

And it has already moved upward. A 2026 umbrella review in Food Science & Nutrition — an umbrella review being a review of other reviews, which sits near the top of the evidence pyramid — discusses the Nutrients meta-analysis in its own assessment of whether vinegar changes body weight. [4]

To be precise, because the stronger version of this claim would be wrong: the umbrella review cites that meta-analysis, it does not pool it. Its own search closed in January 2025. But the citation is there, unqualified, and the word “retraction” appears nowhere in it — because there is nothing in the record to point at.

This is the thing worth taking away, and it is bigger than vinegar. A retraction removes a paper. It does not go back through everything built on top of that paper and take the brick out. The literature keeps the shape the brick gave it.

So does it actually do anything to your weight?

With the 2024 trial gone, the load-bearing study is much older, and it is a better piece of work.

Kondo 2009. [5] A hundred and fifty-five adults finished it. Twelve weeks, double-blind, three groups: a daily drink containing one tablespoon of vinegar, two tablespoons, or none. Everyone kept food diaries and wore a pedometer, and there was no significant difference between the groups in calories, protein, fat, carbohydrate, fibre or steps walked. Visceral fat — the fat around your organs, as opposed to the fat under your skin — was measured by CT scan, not estimated.

At twelve weeks, against a placebo group that gained 0.9 lb: one tablespoon a day lost 2.6 lb (1.2 kg), two tablespoons lost 4.2 lb (1.9 kg). Dose-dependent, statistically significant, visceral fat down. As trials in this corner of nutrition go, that is a good one.

Two things about it rarely travel with the numbers.

First, who ran it. All five authors list the same affiliation: the Central Research Institute of the Mizkan Group Corporation. Mizkan is one of the largest vinegar manufacturers in the world. That does not make the result false, and the trial’s design is genuinely careful. It does mean that the most-cited human evidence that vinegar causes weight loss was produced by a vinegar company, and you are entitled to file it accordingly.

Second, and this is the one nobody quotes: the study kept measuring after people stopped drinking it.

Four weeks after the vinegar stopped, the one-tablespoon group weighed 74.9 kg. That is exactly what they weighed on day one. Every pound back. The two-tablespoon group gave back 3.3 of their 4.2 lb — about 79% of the loss, in a month.

So the honest version of the best trial available reads: roughly four pounds over three months on two tablespoons a day, most of which comes back shortly after you stop.

Which fits the mechanism, incidentally. Vinegar slows how fast your stomach empties — that has been measured directly, and we will come back to it because it is also the source of the main safety caution. A slower stomach means a fuller stomach means, plausibly, eating slightly less. If that is what is happening, then weight coming back when the vinegar stops is not a disappointment. It is exactly what you would predict.

The pooled numbers point the same way and are smaller still. The 2026 umbrella review puts vinegar’s effect on body weight at −2.3 lb (1.06 kg). [4] Worth noting what sits beside that figure: in the same analysis, BMI and waist circumference showed no significant effect. Those three measures are close cousins. When one moves and the other two do not, you are looking at an effect sitting near the edge of what the data can actually resolve.

The benefit that is real is the one nobody sells

Blood sugar. Specifically, what your blood sugar does in the hour or two after you eat.

A 2017 meta-analysis of controlled trials found that taking vinegar with a meal significantly reduced both the glucose and the insulin response afterwards. [6] The glucose effect came out at a standardised mean difference of −0.60, the insulin effect at −1.30. A standardised mean difference is a way of putting different studies on one scale: 0.2 is small, 0.5 is moderate, 0.8 is large. So that is a moderate effect on glucose and a substantial one on insulin.

The 2026 umbrella review, working across ten meta-analyses and 38 underlying trials, lands in the same place and grades its confidence outcome by outcome. [4] Fasting blood glucose down 9.40 mg/dL and after-meal glucose down 14.59 mg/dL, both rated moderate certainty. HbA1c — a rough three-month average of your blood sugar — down 0.70 points, also moderate certainty. Systolic blood pressure down 2.94 mmHg, rated high certainty.

And the things it did not find: no significant effect on fasting insulin, insulin resistance, LDL, HDL, triglycerides, BMI, waist circumference or diastolic blood pressure. Total cholesterol did move, but the reviewers rated that one very low certainty, which is their way of saying do not lean on it.

One caveat that deserves to be visible rather than buried. The HbA1c result carries enormous disagreement between studies. An earlier meta-analysis put the figure at −0.50 with a heterogeneity score of 91%. [7] Heterogeneity is how much the individual trials disagree with one another; 91% means they disagree almost completely. An average computed across studies that found wildly different things is still an average, but it is a shakier object than a single number looks.

That same analysis also found something the wellness framing never mentions: in apparently healthy participants, vinegar appeared to raise fasting glucose. [7] The people most likely to be sold this are the people with the least to gain from it.

None of this makes vinegar a treatment. It is a food that nudges a curve. If you have diabetes, this is a conversation to have with the person managing your care, not a substitution to make on your own — and there is a specific reason for that, coming up next.

The gummy problem

Almost nobody asking this question is drinking vinegar. They are buying gummies.

Here is the uncomfortable history. In 2005, after an adverse event was reported to them, a group of researchers bought eight apple cider vinegar tablet products and tested them for pH, acid content, microbial growth and label accuracy. [8]

They found “considerable variability… between the brands in tablet size, pH, component acid content, and label claims.” Then they wrote the sentence that ought to have ended the category: “Doubt remains as to whether apple cider vinegar was in fact an ingredient in the evaluated products.”

They could not confirm the products contained apple cider vinegar.

That was tablets, it was 2005, and eight products is eight products. We are not going to tell you today’s gummies are the same, because nobody has run the equivalent test on them — which is itself worth sitting with, given how large that market has become in the two decades since.

But the logic runs the other way from how it is sold. Everything above — the glucose curve, the slowed stomach, the modest weight effect — depends on acetic acid, in a measured dose, taken with food. The trials tested vinegar in water at a meal. A sweetened gummy taken whenever is a different object, and the evidence does not transfer to it just because the label uses the same three words.

What it can do to you

The adverse event that prompted that 2005 product test was an oesophageal injury caused by an apple cider vinegar tablet. [8] A concentrated acid tablet that lodges on the way down has time to work.

Teeth are the common one. In 2012 a Dutch dental journal published the case of a 15-year-old with erosive tooth wear that was traced, after a full workup and a study of the erosion pattern, to a daily glass of apple cider vinegar. [10] The same paper contains a detail worth keeping: in North African culture, the authors note, women have used apple cider vinegar for weight loss for generations, and bodybuilders have long done the same. This practice is much older than the industry currently selling it.

The gastric emptying finding is the one that matters clinically. A 2007 crossover study in ten people with type 1 diabetes and diabetic gastroparesis — a condition where the stomach already empties too slowly — measured emptying by ultrasound with and without 30 mL of apple cider vinegar. The rate fell from a median of 27% to 17%. [9] The authors concluded this “might be a disadvantage regarding to their glycaemic control.” The mechanism that helps a healthy person is a liability if your stomach is already the problem.

Two case reports round it out, and they are case reports — single patients, no control group, no way to know how common any of it is. In 1998, a kidney journal described low blood potassium, elevated renin and osteoporosis in a patient who had been ingesting large amounts of cider vinegar. [11] In 2025, a case report described liver injury in a 60-year-old man with a long history of vinegar consumption, which improved after he stopped. [12]

Neither is a reason for alarm. Both are reasons not to treat “more is better” as a plan. Notice what the case reports have in common — the word that keeps appearing is large.

If you are going to do it anyway

Nothing here says don’t. It says know what you bought.

The tested dose is one to two tablespoons (15–30 mL) a day, diluted in water, taken with or just before a meal. That is what the trials used and there is no evidence that more does more. Dilute it — never shots. Use a straw if you can, rinse with water afterwards, and do not brush your teeth straight away, because brushing enamel that acid has just softened is worse than leaving it alone for half an hour.

Take it with food. That is where the glucose evidence actually sits, and the popular before-bed ritual is not what any of these trials tested.

And talk to a doctor first if you take medication for diabetes, if you have gastroparesis or any condition that slows digestion, if you have low potassium, or if you have kidney problems. Those are not generic disclaimers — each one maps to a specific finding above.

The verdict

Apple cider vinegar does something. It blunts the blood-sugar rise after a meal, reliably enough to have survived several meta-analyses, and it probably nudges body weight by a couple of pounds over a few months by making you a bit fuller.

It is not a fat burner. The trial that made it look like one was retracted, the best surviving trial was run by a vinegar company and showed the weight coming back within a month of stopping, and the pooled effect on your waistline is not statistically distinguishable from nothing.

We have it at Preliminary rather than Unsupported, because there is a real signal here with a demonstrated mechanism, and pretending otherwise would be its own kind of dishonesty. What would move it: a large, independently funded, pre-registered trial running well past twelve weeks, with a follow-up period after the vinegar stops. That last part is the one that keeps not being done — and on the evidence of Kondo’s own washout, it is the part that would settle it.

If you want the version of this that costs nothing and has better evidence behind it: eating slower and putting protein and fibre at the front of a meal blunts the same curve, and nobody has to sell you a gummy for it.

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