Apple cider vinegar

What it is

Apple cider vinegar is made by fermenting apples, first to alcohol and then to acetic acid. It is one of the three most common types of vinegar and is used worldwide as a flavouring and preservative. Besides acetic acid it contains flavonoids including gallic acid, catechin, caffeic acid and ferulic acid. It is among the most acidic substances people routinely drink.

What the research says

The human evidence is made of small, short trials, several of them unblinded, and it points to modest metabolic changes rather than the weight-loss effect the product is usually sold for. A 2021 meta-analysis of nine studies found small reductions in total cholesterol, fasting glucose and HbA1c, but no effect on LDL, HDL, fasting insulin or insulin resistance, with high statistical heterogeneity and the authors themselves saying reliable conclusions could not be drawn for some outcomes. The widely reported 2024 trial claiming apple cider vinegar aids weight loss was retracted in 2025 for unreliable data and statistics. Harms are documented: an 8-week randomised trial found measurable erosive tooth wear, and case reports describe chemical burns and corrosive injury from concentrated or undiluted vinegar.

Evidence grade: Limited evidence.

What goes wrong

Drinking vinegar twice daily for eight weeks measurably increased erosive tooth wear in a randomised trial. (Source 1)

• Randomized trial, Low certainty.
• Size: healthy adults in an 8-week randomised trial.
• Who: healthy adults taking vinegar for insulin sensitivity and visceral fat.
• How long: 8 weeks.
• Result: mean basic erosive wear examination (BEWE) scores unchanged in the control group and increased 18% in the vinegar group (P = .038)
• Funding: not stated; registered at ClinicalTrials.gov NCT03577834.

Mean BEWE scores did not change in the control group but increased 18% in the vinegar group over the 8-week study

Applying apple cider vinegar to the skin as an internet 'mole removal' remedy caused chemical burns in a 14-year-old. (Source 2)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: a 14-year-old girl.
• How long: several drops applied daily for three days under occlusion.
• Result: erythema and irritation by day two; poorly defined erosions on the left nasal ala and alar crease requiring topical antibiotic treatment.
• Funding: not stated.

She subsequently applied several drops of apple cider vinegar daily for three days straight to the nevi on her nose, occluding the area with bandages.

Drinking a vinegar beverage daily without adequate dilution caused corrosive oesophageal ulceration in a 15-year-old. (Source 3)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: a 15-year-old boy drinking a pomegranate-fermented vinegar beverage, not apple cider vinegar specifically.
• How long: daily for about one month; symptoms for 2 weeks.
• Result: multiple longitudinal oesophageal ulcers, mucosal haemorrhage and denuded mucosa on endoscopy; treated with corticosteroid, antibiotics and a week of fasting.
• Funding: not stated.

Multiple longitudinal ulcers, concurrent mucosal hemorrhage, and denuded mucosa were noted in the whole of the esophagus via an endoscopic examination.

The authors of that case conclude vinegar beverages should be treated as corrosive agents. (Source 3)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: adolescent drinking undiluted vinegar beverage.
• How long: one month of daily use.
• Result: acidic burns and destruction of the upper gastrointestinal surface.
• Funding: not stated.

Overall, continuous consumption of a vinegar beverage can result in acidic burns and destruction of the surface of the upper gastrointestinal tract.

What the evidence supports

A meta-analysis of clinical trials found small reductions in total cholesterol, fasting glucose and HbA1c with apple cider vinegar. (Source 4)

• Meta-analysis, Low certainty.
• Size: nine studies including 10 study arms.
• Who: adults, including subgroups with type 2 diabetes and apparently healthy participants.
• How long: trials of at least 2 weeks; subgroup analyses at more than 8 weeks.
• Result: total cholesterol -6.06 mg/dL (95% CI -10.95, -1.17; I2 39%); fasting plasma glucose -7.97 mg/dL (95% CI -13.74, -2.21; I2 75%); HbA1c -0.50 (95% CI -0.90, -0.09; I2 91%)
• Funding: not stated.

We found that ACV consumption significantly decreased serum total cholesterol (− 6.06 mg/dL; 95% CI: − 10.95, − 1.17; I2: 39%), fasting plasma glucose (− 7.97 mg/dL; 95% CI: − 13.74, − 2.21; I2: 75%), and HbA1C concentrations (− 0.50; 95% CI: − 0.90, − 0.09; I2: 91%).

An unblinded randomised trial in people with type 2 diabetes reported lower HbA1c and LDL with 30 mL of apple cider vinegar daily, but had no placebo. (Source 5)

• Randomized trial, Low certainty.
• Size: adults with type 2 diabetes randomised to apple cider vinegar or control.
• Who: adults with type 2 diabetes; both groups given the same healthy-diet advice.
• How long: 8 weeks.
• Result: fasting blood glucose fell significantly only in the vinegar group (p = 0.01); HbA1c differed between groups (p < 0.001); LDL decreased in the vinegar group (p < 0.001); total cholesterol, LDL/HDL and Chol/HDL fell versus control (p = 0.003, p = 0.001, p = 0.001)
• Funding: independent; supported by Ahvaz Jundishapur University of Medical Sciences (NRC-9706), part of a Master's thesis.

There was a significant difference in hemoglobin A1C levels between the two groups (p < 0.001) after eight weeks.

What the evidence does not support

The same meta-analysis found no effect of apple cider vinegar on LDL cholesterol, HDL cholesterol, fasting insulin or insulin resistance. (Source 4)

• Meta-analysis, Low certainty.
• Size: nine studies including 10 study arms.
• Who: adults.
• How long: at least 2 weeks.
• Result: no significant effect on LDL-C, HDL-C, fasting insulin or HOMA-IR; apple cider vinegar appeared to increase fasting glucose and HDL-C in apparently healthy participants.
• Funding: not stated.

No significant effect of ACV consumption was found on serum LDL-C, HDL-C, fasting insulin concentrations, or HOMA-IR.

The widely publicised 2024 randomised trial reporting that apple cider vinegar aids weight loss was retracted in 2025 because the results were unreliable. (Source 6)

• Randomized trial, Very low certainty.
• Size: a small clinical trial in adolescents and young adults with overweight and obesity.
• Who: Lebanese adolescents and young adults with overweight and obesity.
• How long: 12 weeks as originally reported.
• Result: retracted; statisticians could not replicate the results, multiple analytical errors were identified, and there were irregularities in the data set.
• Funding: not stated.

The retraction was prompted by concerns raised about the quality of the work, including the approach to statistical analysis of the data; implausible statistical values; the reliability of the raw data; inadequate reporting of methods; and lack of prospective trial registration, which breaches BMJ Group's editorial policy.

Where the evidence is mixed

The authors of the meta-analysis state that the small number of studies means reliable conclusions cannot be drawn for insulin and insulin resistance. (Source 4)

• Meta-analysis, Very low certainty.
• Size: nine studies.
• Who: adults.
• How long: at least 2 weeks.
• Result: high between-study heterogeneity (I2 up to 91%); few studies for insulin and HOMA-IR.
• Funding: not stated.

The number of included studies, in particular in terms of insulin and HOMA-IR, was relatively low, thereby precluding reliable conclusions to be drawn.

That trial's authors identify the absence of a placebo as a limitation. (Source 5)

• Randomized trial, Low certainty.
• Size: adults with type 2 diabetes.
• Who: adults with type 2 diabetes.
• How long: 8 weeks.
• Result: no placebo control, so expectation effects cannot be excluded.
• Funding: independent; university supported.

One of the limitations of this study is the lack of a placebo.

What official bodies say

The journal's integrity editor stated the retracted trial's results should no longer be used in reporting on apple cider vinegar and weight loss. (Source 6)

• Official position, Certainty not rated.
• Size: not applicable.
• Who: not applicable.
• How long: statement issued 2025.
• Result: the results of the study are described as unreliable.
• Funding: not applicable.

at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting.

Where the research disagrees

Whether apple cider vinegar helps people lose weight

• BMJ Group, retracting the 2024 trial that generated the claim, retraction of a randomised trial after statistical review: at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting. (Source 6)
• The meta-analysis of apple cider vinegar trials, which examined lipids and glucose rather than weight, meta-analysis of nine studies with high heterogeneity: We found a significant favorable effect of ACV consumption on FPG and blood lipid levels. (Source 4)

How much

• Reference intake: No dietary reference intake exists. Apple cider vinegar is a fermented food and flavouring rather than a nutrient: it is described as one of the three most common types of vinegar, produced by fermenting apples, consumed worldwide as a flavouring and preservative. (Source 4)
• Upper limit: No tolerable upper intake level or acceptable daily intake has been identified in the sources we reached. The meta-analysis instead stratified trials by dose, using a cut-off of 15 mL per day. (Source 4)
• Studied: A trial in adults with type 2 diabetes gave 30 mL of apple cider vinegar per day for eight weeks. (Source 5)
• Studied: A tooth-wear trial gave two tablespoons of vinegar in a cup of water (3.6 g acetic acid) twice daily at mealtime, against a vinegar pill containing 0.045 g acetic acid. (Source 1)
• Studied: A meta-analysis found significant reductions in total cholesterol and triglycerides in the subgroup of trials using 15 mL per day or less. (Source 4)

A common belief, and what the research shows

The belief: A daily shot of apple cider vinegar burns fat and causes weight loss.

What the research shows: The single trial that drove this belief no longer stands. BMJ Group retracted it, citing 'the approach to statistical analysis of the data; implausible statistical values; the reliability of the raw data; inadequate reporting of methods; and lack of prospective trial registration', and the journal's integrity editor said 'at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting.' The meta-analytic evidence that does exist concerns cholesterol and blood glucose, not body weight, and even there 'No significant effect of ACV consumption was found on serum LDL-C, HDL-C, fasting insulin concentrations, or HOMA-IR.'

Questions and answers

What is it?

Apple cider vinegar is the product of fermenting apples, first into alcohol and then into acetic acid. It is one of the three most common vinegars and is used around the world as a flavouring and a preservative. Alongside acetic acid it contains plant polyphenols such as gallic acid, catechin, caffeic acid and ferulic acid. (Source 4)

What does it do in the body?

In trials lasting weeks it has been associated with small falls in total cholesterol, fasting glucose and HbA1c. It has not been shown to change LDL, HDL, fasting insulin or insulin resistance. The trials are few and differ greatly from one another, so the size of any real effect is uncertain. (Source 4)

Is it good or bad for you?

As a diluted food ingredient it is unremarkable. As a daily concentrated 'health' drink the balance shifts: an eight-week randomised trial found measurable erosion of tooth enamel, and case reports describe chemical burns on skin and corrosive oesophageal injury from undiluted vinegar drinks. The metabolic benefits reported are small and uncertain; the acid damage is directly observed. (Source 1)

How do you get more of it?

It is a food, bought as a bottled vinegar or as capsules, tablets and gummies. Trials have used measured liquid doses: one gave adults with type 2 diabetes 30 mL a day for eight weeks, another gave two tablespoons diluted in a cup of water twice daily. Capsule products can contain far less acetic acid than the liquid. (Source 1)

If it is harmful, what reduces it?

There is nothing to clear from the body: acetic acid is metabolised normally and vinegar is an ordinary food acid. What the literature describes reducing is the damage from contact with it, by diluting it rather than drinking it neat. In the corrosive injury case the manufacturer had specified dilution and the patient had not followed it. (Source 3)

Why might someone be low in it or missing it?

Does not apply. Apple cider vinegar is a flavouring and preservative, not a nutrient the body requires, so no one is deficient in it and there is no medical or dietary reason a person would be low in it. (Source 4)

Which whole foods contain it or feed it?

Apple cider vinegar itself is the whole food: fermented apples. Its active acid, acetic acid, is what all vinegars are made of, so any vinegar, and fermented and pickled foods preserved in vinegar, supply the same compound. (Source 4)

What happens if you do not have it?

Nothing happens. There is no deficiency state and no health consequence of never consuming it. The claimed consequence people worry about, missing out on weight loss, rests on a trial that has been retracted as unreliable. (Source 6)

How can you test for it?

There is no test for apple cider vinegar status, because it is not a body constituent. The measurements used in trials are ordinary metabolic blood tests taken before and after a period of intake, such as fasting glucose, HbA1c and lipid panels, and dental examination scores for erosion. We found no validated test of apple cider vinegar itself. (Source 5)

We searched: Searched the 2021 meta-analysis of apple cider vinegar on lipids and glycaemic parameters, the 2023 randomised trial in type 2 diabetes, and the 2021 erosive tooth wear trial; none describes a test for apple cider vinegar in a person.

References

1. Journal of Medicinal Food. Evidence That Daily Vinegar Ingestion May Contribute to Erosive Tooth Wear in Adults. 2021. PMID 33297831, DOI 10.1089/jmf.2020.0108. Read the source
2. The Journal of Clinical and Aesthetic Dermatology. Chemical Burn from Vinegar Following an Internet-based Protocol for Self-removal of Nevi. 2015. Read the source
3. Clinical Endoscopy. Corrosive Esophageal Injury due to a Commercial Vinegar Beverage in an Adolescent. 2020. PMID 31405264, DOI 10.5946/ce.2019.066. Read the source
4. BMC Complementary Medicine and Therapies. The effect of apple cider vinegar on lipid profiles and glycemic parameters: a systematic review and meta-analysis of randomized clinical trials. 2021. PMID 34187442, DOI 10.1186/s12906-021-03351-w. Read the source
5. Frontiers in Clinical Diabetes and Healthcare. The improvement effect of apple cider vinegar as a functional food on anthropometric indices, blood glucose and lipid profile in diabetic patients: a randomized controlled clinical trial. 2023. DOI 10.3389/fcdhc.2023.1288786. Read the source
6. BMJ Group (news release, distributed via EurekAlert!). BMJ Group retracts trial on apple cider vinegar and weight loss. 2025. Read the source