Apple Cider Vinegar: What It Can and Can't Do

Short answer: Apple cider vinegar (ACV) can modestly lower the spike in blood sugar after a meal, and small trials suggest small drops in fasting glucose and body weight. [S01] [S02] [S04] It is not a reliable weight-loss tool: Mayo Clinic says it isn't likely to cause weight loss, [S07] and a widely shared 2024 trial that reported big losses was retracted in September 2025. [S03] Its downsides are mostly about acid: worn tooth enamel, throat irritation, and possible low potassium in people on certain drugs. [S07] [S08]

ACV is one of the most searched home remedies, and the claims run from "melts belly fat" to "cures diabetes." Here's what the research actually tested, how big the effects were, and who should be careful.

What apple cider vinegar is

ACV is vinegar made from fermented apple juice. Its main acid, acetic acid, is the compound most studies focus on, and researchers describe vinegar as one of the most acidic things people regularly consume. [S08] Both the possible benefits and the main side effects trace back to that acid.

Blood sugar: the strongest evidence

After a meal

This is where vinegar has the most consistent data. A 2017 meta-analysis of clinical trials found that people who had vinegar with a meal had a smaller rise in blood glucose and insulin afterward than people who didn't. [S01] The authors concluded that vinegar could be an "adjunctive tool" for glycemic control, meaning an add-on, not a treatment. [S01]

Fasting glucose and HbA1c

A 2025 review pooled seven controlled studies in people with type 2 diabetes. ACV lowered fasting blood sugar by about 22 mg/dL and HbA1c by 1.53 points on average, with larger effects at doses above 10 mL a day. [S04] It didn't improve insulin resistance as measured by HOMA-IR, and fasting insulin went slightly up. [S04]

An earlier 2021 meta-analysis of nine studies found smaller effects: fasting glucose fell by about 8 mg/dL and HbA1c by 0.5 points, with large differences between studies. [S05] In apparently healthy participants, the pooled data actually showed a slight rise in fasting glucose. [S05]

Those numbers come from small, short trials with different doses and products, so treat them as a signal rather than a promise. If you have diabetes, vinegar doesn't replace medicine, and adding it to insulin or other glucose-lowering drugs is a conversation to have with your prescriber first. [S07]

Weight loss: smaller than the headlines

A 2025 meta-analysis in Nutrients pooled 10 randomized trials with 789 adults who had overweight, obesity or type 2 diabetes. Daily ACV for at least four weeks lowered body weight, BMI and waist circumference by modest amounts, and it had no effect on the other body-composition measures the authors looked at. [S02] The benefit showed up mainly in studies that used about 30 mL (2 tablespoons) a day for up to 12 weeks. [S02]

The retracted trial

Much of the 2024 buzz came from a trial in Lebanese adolescents and young adults that reported unusually large weight losses. That paper was retracted on September 23, 2025. [S03] The 2025 Nutrients meta-analysis included it among its trials, so its pooled result leans partly on data that is no longer part of the published record. [S02] [S03] We don't use the retracted trial as evidence here.

What's left is consistent with Mayo Clinic's take: research hasn't shown ACV causes meaningful weight loss, and the studies are small. [S07] A 2020 systematic review of 13 human studies reached a similar conclusion: there may be some benefit, but there isn't enough high-quality research to say so with confidence. [S06]

Cholesterol and heart health

The 2021 meta-analysis found a small drop in total cholesterol, about 6 mg/dL. [S05] There was no significant change in LDL ("bad") or HDL ("good") cholesterol. [S05] That's not enough to count ACV as a heart-health treatment.

Putting it on your skin

ACV is also promoted online as a skin toner, wart remedy or scalp rinse. The trials above tested drinking it, not applying it. Applied to skin, it can cause a chemical burn; dermatologists have published a case report describing one. [S12] If you want to treat a skin problem, that's a job for a product tested for it, or a clinician.

Why the evidence stays "maybe"

Three things keep ACV research from reaching firm conclusions.

The trials are small and short. The 10 weight trials in the 2025 meta-analysis averaged fewer than 80 people each, and the clearest effects came from studies lasting 12 weeks or less. [S02] Nobody has shown what happens after a year of daily use.

The results vary a lot from study to study. Statisticians measure this with a figure called I², where higher means the studies disagree more. For weight it was 62%, and for BMI 83%, in the 2025 analysis. [S02] For HbA1c in the 2021 analysis it was 91%. [S05] When results scatter that widely, a single pooled average hides a lot of uncertainty.

Doses and products differ. Studies used different amounts, from 15 mL or less to about 30 mL a day, and different products. [S02] [S05] The 2025 diabetes review found that each extra milliliter a day was linked to about 1.3 mg/dL lower fasting blood sugar, [S04] but that kind of dose trend in a handful of trials isn't proof that more is better, and higher doses carry more acid.

The 2020 systematic review summed it up: more large, long-term, low-bias studies are needed before anyone can draw definitive conclusions. [S06] That's a fair way to hold all of the findings above.

Side effects and safety

A 2020 review judged the risk of side effects small when ACV is taken in recommended amounts and ways. [S06] The problems show up with large doses, undiluted vinegar or the wrong format.

Teeth

In an eight-week trial, adults who drank 2 tablespoons of vinegar in a cup of water twice a day saw an 18% rise in tooth erosion scores, while the control group saw none. [S08] That trial used diluted vinegar, so diluting it doesn't remove the risk to enamel.

Throat and stomach

ACV is acidic enough to irritate the throat. [S07] In people with type 1 diabetes and gastroparesis, a pilot study found that ACV slowed stomach emptying even further, which could make blood sugar harder to manage. [S10]

Potassium and bones

One case report describes low potassium and osteoporosis in a person who drank large amounts of cider vinegar. [S11] Mayo Clinic warns that ACV may interact with diuretics and insulin, both of which can lower potassium, and with the supplements licorice and horsetail. [S07] Our guide to herb-drug interactions explains how to check a supplement against your medicines.

Pills and gummies

When researchers tested eight ACV tablet products after an esophageal injury was reported to them, they found wide variation in tablet size, acidity, acid content and label claims, and doubt about whether ACV was in them at all. [S09] Mayo Clinic also notes that an ACV tablet stuck in the throat can cause lasting pain. [S07]

How people use it, if they do

Studies that found effects mostly used 1 to 2 tablespoons (15 to 30 mL) a day, diluted in water or used in food, for up to 12 weeks. [S02] [S07] Mayo Clinic says most people can use small amounts safely and that it may cause fewer side effects if you use it in food rather than drink it. [S07] A vinaigrette on a salad with dinner is the simplest version of the "vinegar with a meal" studies.

ACV sits in the same category as many popular supplements we review: a real but modest effect in some studies, and much bigger claims online. Our reviews of berberine and turmeric and curcumin follow the same approach.

Who should ask a clinician first

• People taking insulin or other diabetes medicines [S04] [S07]
• People taking diuretics or anything else that lowers potassium [S07]
• People with gastroparesis [S10]
• People with tooth erosion or a sensitive throat [S07] [S08]