How Does Apple Cider Vinegar Work in the Body?

Apple cider vinegar works mainly through its major compound: acetic acid, formed during the fermentation of apple sugar. It is this acid that is behind the most studied effects — modulation of the glycaemic response, modest changes in weight and waist circumference, and effects on the lipid profile — and not the enzymes or the "mother" of the vinegar, whose role in the human body is much less characterised. In short: the documented effects are real but modest, they depend on dose and duration, and they do not turn vinegar into a treatment.

This page explains what is known, what is not known and how to interpret the numbers you see out there. If you are looking first for the general benefits, see what are the health benefits of apple cider vinegar.

What apple cider vinegar is and what it contains

Apple cider vinegar results from a two-step fermentation: yeasts convert the sugars in apples into alcohol, and then acetic acid bacteria convert that alcohol into acetic acid. The final product is mostly water and acetic acid, with trace amounts of other compounds. Enzymes, polyphenols and the bacteria of the "mother" exist, but the available clinical evidence focuses on acetic acid — it is to this that the effects observed in trials are attributed. For a detailed description of the ingredient, see the apple cider vinegar page.

How does acetic acid act in the body?

The best-described mechanism is the effect of acetic acid on carbohydrate digestion: by reducing the speed at which the stomach empties and by interfering with the activity of digestive enzymes, the rise in glucose after a meal tends to be slower. This is a plausible explanation and consistent with the trial results, but note that most studies measure the final effect (blood glucose, HbA1c, weight) and not the mechanism itself. Other hypotheses — an effect on satiety, on colonic fermentation or on lipid metabolism — are less established.

What studies show about blood sugar

This is the area with the most consistent evidence. In a meta-analysis of 9 randomised clinical trials in adults, consumption of apple cider vinegar reduced fasting plasma glucose by about 8 mg/dL and HbA1c by about 0.50 points, with no significant effect on triglycerides, LDL or HDL ¹. A later meta-analysis, with 25 trials and 1320 adults, found average reductions of about 21 mg/dL in fasting blood glucose and about 0.91 percentage points in HbA1c, with the effect most marked in the subgroup of participants with diabetes ². In a network meta-analysis that compared six plants in adults with type 2 diabetes, apple cider vinegar was the intervention with the greatest effect on fasting blood glucose and one of the two with a significant effect on HbA1c ³.

Two important caveats: these studies were carried out in specific populations (mainly adults with type 2 diabetes or with excess weight) and the heterogeneity between trials is high, which means that the average values do not describe what would happen to a particular person. If you have diabetes or take medication for blood glucose, talk to your doctor before adding vinegar to your routine.

Weight and body composition: what the evidence allows us to say

A meta-analysis of 10 randomised trials, with 789 adult participants with type 2 diabetes and/or excess weight, assessed at least 4 weeks of apple cider vinegar consumption and found significant average reductions in body weight, BMI and waist circumference, but with no significant effects on the remaining body composition parameters assessed ⁴. In other words: the effects exist, they are small to moderate in magnitude and they do not amount to a weight-loss strategy on their own. A meta-analysis with 25 trials found no significant effect on BMI ², which shows how conclusions vary with the studies included. For a more detailed analysis of this topic, see apple cider vinegar for weight loss: does it work?.

Cholesterol and other cardiometabolic markers

The results on lipids are less consistent than those on blood glucose. In the meta-analysis of 9 trials, consumption of apple cider vinegar reduced total cholesterol by about 6 mg/dL, with no significant effect on triglycerides, LDL or HDL ¹. The meta-analysis of 25 trials found an average reduction of about 6.7 mg/dL in total cholesterol, also with no significant effects on BMI, insulin resistance, serum insulin, triglycerides, LDL or HDL ². In other words: there is a small signal in total cholesterol, but there is no evidence that vinegar changes the full lipid profile in a relevant way.

Digestion, microbiota and colonic fermentation

The idea that vinegar "improves digestion" is popular, but direct evidence in humans is limited. In a randomised crossover trial with 20 healthy adults aged 18 to 45, a diet enriched with short-chain fatty acids — which included apple cider vinegar, as well as resistant starch and inulin — for 21 days increased faecal concentrations of short-chain fatty acids and reduced faecal ammonia ⁵. This is an interesting result, but vinegar was only one of the components of the diet tested, so the effect cannot be attributed to it in isolation. For what is known about bloating and discomfort, see can apple cider vinegar help with bloating?.

What about skin? What one trial showed

Topical use is often associated with skin benefits. In a randomised pilot trial with 11 participants with atopic dermatitis and 11 healthy controls, daily 10-minute soaks of one arm in apple cider vinegar diluted to 0.5% acetic acid for 14 days did not change the skin's bacterial microbiome or the abundance of Staphylococcus aureus ⁶. This is a small study and in a specific skin condition, but it serves as a warning against the idea that vinegar "rebalances" the skin in a generalised way. Undiluted vinegar on the skin can cause irritation and chemical burns.

If you use liquid vinegar on the skin, always dilute it — undiluted vinegar can irritate and even cause chemical burns. The same care applies to consumption: drinking pure vinegar harms the oesophagus and tooth enamel.

What apple cider vinegar does not do

It is worth being clear about what the evidence does not support:

• There are no studies demonstrating "detoxification" or an effect on liver function — the liver and kidneys already perform these functions without help.
• There is no evidence that it increases immunity in a measurable way; the authorised claims in the EU for the immune system belong to specific vitamins and minerals, not to botanicals ⁷.
• There is no evidence of changes in the volume or composition of urine, nor of a change in the body's acid-base balance.
• A randomised crossover trial with 20 participants who did not form kidney stones found no significant changes in 24-hour urinary parameters after consumption of apple cider vinegar ⁸.

Doses used in studies and what the gummies label says

The doses tested in trials vary considerably. In a 12-week randomised trial with 94 women with polycystic ovary syndrome, insulin resistance and metabolic syndrome, already on metformin treatment, capsules of 1500 mg per day were used ⁹ — note that this is a population with a specific condition and on medication, so the results do not automatically transfer to healthy adults. Other trials included in the meta-analyses used different doses and formulations, often lower.

Appetite Control Gummies provide 1000 mg of apple cider vinegar per serving of 2 gummies, plus vitamin B6 (1 mg, 71% NRV), folic acid (400 µg, 200% NRV), vitamin B12 (2.4 µg, 96% NRV), iodine (100 µg, 67% NRV), pomegranate juice powder (80 mg) and beetroot juice powder (80 mg). The directions on the label are to chew 2 gummies per day, preferably after a meal, without exceeding the recommended daily dose. Doses used in studies are not instructions for use: always follow the label of the product you consume.

As for the B-complex vitamins and iodine present in the formula, the authorised claims in the EU are specific: vitamin B6 contributes to normal energy-yielding metabolism, vitamin B12 contributes to the normal functioning of the nervous system and iodine contributes to normal energy-yielding metabolism ⁷. This describes the physiological role of the nutrients, not an effect of the product.

Practical comparison: liquid, capsules and gummies

Format	Advantages	Limitations
Diluted liquid vinegar	Format used in most trials; easy to dilute in water	Intense taste; acidity can upset the stomach and tooth enamel if not diluted
Capsules	Exact dose and no contact with tooth enamel; format used in some trials	They do not have the taste of vinegar, but they also do not have the volatile compounds
Gummies	Convenient and pleasant to take; fixed dose per serving	There are no studies comparing gummies with liquid or capsules in terms of effects on the body

There are no trials that directly compare these formats for clinical outcomes, so it is not possible to state that one is equivalent or superior to another. What can be said is that the dose per serving is on the label and that adherence to the chosen format is, in practice, the factor that most influences consistency of consumption. See also apple cider vinegar vs. gummies.

How to include it in your routine and when to talk to a professional

The timing of the dose is mainly a matter of digestive comfort: the gummies label suggests after a meal. If you use liquid vinegar, always dilute it in water and use a straw to protect your teeth; never drink it pure. To go deeper, see the best time to take apple cider vinegar and how to include apple cider vinegar in your routine.

For a practical reference on amounts, see how much apple cider vinegar should you take per day. If your question is digestion, this analysis on digestion details what the evidence shows.

Talk to a health professional before starting if you are pregnant or breastfeeding, if you have a diagnosed condition (especially diabetes, gastro-oesophageal reflux or kidney disease), if you take regular medication or if you intend to give apple cider vinegar to children — there are no established doses for children and consumption of undiluted vinegar is not advised in this age group. The Appetite Control Gummies label also includes the warning that they contain polyols and that excessive consumption may have laxative effects, as well as recommending consultation with a health professional in case of pregnancy, breastfeeding, illness or taking medication.

Frequently asked questions

How does apple cider vinegar work in the body?

The most studied effect is due to acetic acid, which slows down the digestion of carbohydrates and softens the rise in glucose after a meal. Meta-analyses of randomised trials show modest reductions in fasting blood glucose and HbA1c, especially in adults with type 2 diabetes or excess weight. It is not a treatment and does not replace medication.

How long does it take to notice effects?

The trials included in the meta-analyses typically lasted between 4 and 12 weeks, and it was over this horizon that differences in blood glucose, weight and waist circumference were observed. There is no evidence of immediate effects, and any individual perception depends on diet and baseline lifestyle.

Do apple cider vinegar gummies work as well as liquid vinegar?

There are no studies comparing gummies with liquid vinegar or capsules in terms of clinical outcomes, so equivalence cannot be stated. What is known is the dose per serving indicated on the label and that the convenience of the format may help maintain consistent consumption. Doses used in studies are not instructions for use.

Does apple cider vinegar help with weight loss?

A meta-analysis of 10 randomised trials in adults with type 2 diabetes and/or excess weight found small average reductions in weight, BMI and waist circumference after at least 4 weeks. Another meta-analysis found no effect on BMI. This is a modest effect, which does not replace a balanced diet and regular physical activity.

Is apple cider vinegar safe for daily use?

In diluted amounts, daily consumption is generally well tolerated, but undiluted vinegar can irritate the oesophagus and wear down tooth enamel. Gummies have the advantage of avoiding this direct contact with the teeth. If you have reflux, kidney disease, diabetes or take medication, talk to a health professional first.

Can I give apple cider vinegar to children?

There are no established doses for children and consumption of undiluted vinegar is not advised in this age group. Any supplement with apple cider vinegar should be discussed with a health professional before being given to a child.